\C{config} Configuring PuTTY
-This chapter describes all the configuration options in PuTTY.
+This chapter describes all the \i{configuration options} in PuTTY.
PuTTY is configured using the control panel that comes up before you
start a session. Some options can also be changed in the middle of a
to specify in order to open a session at all, and also allows you to
save your settings to be reloaded later.
-\S{config-hostname} The host name section
+\S{config-hostname} The \i{host name} section
\cfg{winhelp-topic}{session.hostname}
connection by host name}, contains the details that need to be
filled in before PuTTY can open a session at all.
-\b The \q{Host Name} box is where you type the name, or the IP
-address, of the server you want to connect to.
+\b The \q{Host Name} box is where you type the name, or the \i{IP
+address}, of the server you want to connect to.
-\b The \q{Protocol} radio buttons let you choose what type of
-connection you want to make: a raw connection, a Telnet connection, an
-rlogin connection or an SSH connection. (See \k{which-one} for a
-summary of the differences between SSH, Telnet and rlogin, and
-\k{using-rawprot} for an explanation of \q{raw} connections.)
+\b The \q{Connection type} radio buttons let you choose what type of
+connection you want to make: a \I{raw TCP connections}raw
+connection, a \i{Telnet} connection, an \i{Rlogin} connection, an
+\i{SSH} connection, or a connection to a local \i{serial line}. (See
+\k{which-one} for a summary of the differences between SSH, Telnet
+and rlogin; see \k{using-rawprot} for an explanation of \q{raw}
+connections; see \k{using-serial} for information about using a
+serial line.)
-\b The \q{Port} box lets you specify which port number on the server
-to connect to. If you select Telnet, Rlogin, or SSH, this box will
-be filled in automatically to the usual value, and you will only
-need to change it if you have an unusual server. If you select Raw
-mode, you will almost certainly need to fill in the \q{Port} box.
+\b The \q{Port} box lets you specify which \i{port number} on the
+server to connect to. If you select Telnet, Rlogin, or SSH, this box
+will be filled in automatically to the usual value, and you will
+only need to change it if you have an unusual server. If you select
+Raw mode, you will almost certainly need to fill in the \q{Port} box
+yourself.
-\S{config-saving} Loading and storing saved sessions
+If you select \q{Serial} from the \q{Connection type} radio buttons,
+the \q{Host Name} and \q{Port} boxes are replaced by \q{Serial line}
+and \q{Speed}; see \k{config-serial} for more details of these.
+
+\S{config-saving} \ii{Loading and storing saved sessions}
\cfg{winhelp-topic}{session.saved}
\b To save your default settings: first set up the settings the way
you want them saved. Then come back to the Session panel. Select the
-\q{Default Settings} entry in the saved sessions list, with a single
+\q{\i{Default Settings}} entry in the saved sessions list, with a single
click. Then press the \q{Save} button.
-Note that PuTTY does not allow you to save a host name into the
-Default Settings entry. This ensures that when PuTTY is started up,
-the host name box is always empty, so a user can always just type in
-a host name and connect.
-
If there is a specific host you want to store the details of how to
connect to, you should create a saved session, which will be
separate from the Default Settings.
saved session name.) Then press the \q{Save} button. Your saved
session name should now appear in the list box.
+\lcont{
+You can also save settings in mid-session, from the \q{Change Settings}
+dialog. Settings changed since the start of the session will be saved
+with their current values; as well as settings changed through the
+dialog, this includes changes in window size, window title changes
+sent by the server, and so on.
+}
+
\b To reload a saved session: single-click to select the session
name in the list box, and then press the \q{Load} button. Your saved
settings should all appear in the configuration panel.
\b To modify a saved session: first load it as described above. Then
make the changes you want. Come back to the Session panel, and press
the \q{Save} button. The new settings will be saved over the top of
-the old ones
+the old ones.
\lcont{
To save the new settings under a different name, you can enter the new
configuration. If you change your preferences and update Default
Settings, you must also update every saved session separately.
-Saved sessions are stored in the Registry, at the location
+Saved sessions are stored in the \i{Registry}, at the location
\c HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\Sessions
If you need to store them in a file, you could try the method
described in \k{config-file}.
-\S{config-closeonexit} \q{Close Window on Exit}
+\S{config-closeonexit} \q{\ii{Close Window} on Exit}
\cfg{winhelp-topic}{session.coe}
Finally in the Session panel, there is an option labelled \q{Close
-Window on Exit}. This controls whether the PuTTY session window
+Window on Exit}. This controls whether the PuTTY \i{terminal window}
disappears as soon as the session inside it terminates. If you are
likely to want to copy and paste text out of the session after it
has terminated, or restart the session, you should arrange for this
\cfg{winhelp-topic}{logging.main}
-The Logging configuration panel allows you to save log files of your
+The Logging configuration panel allows you to save \i{log file}s of your
PuTTY sessions, for debugging, analysis or future reference.
The main option is a radio-button set that specifies whether PuTTY
-will log anything at all. The options are
+will log anything at all. The options are:
-\b \q{Logging turned off completely}. This is the default option; in
-this mode PuTTY will not create a log file at all.
+\b \q{None}. This is the default option; in this mode PuTTY will not
+create a log file at all.
-\b \q{Log printable output only}. In this mode, a log file will be
+\b \q{Printable output}. In this mode, a log file will be
created and written to, but only printable text will be saved into
it. The various terminal control codes that are typically sent down
an interactive session alongside the printable text will be omitted.
This might be a useful mode if you want to read a log file in a text
editor and hope to be able to make sense of it.
-\b \q{Log all session output}. In this mode, \e{everything} sent by
+\b \q{All session output}. In this mode, \e{everything} sent by
the server into your terminal session is logged. If you view the log
file in a text editor, therefore, you may well find it full of
strange control characters. This is a particularly useful mode if
else can replay the session later in slow motion and watch to see
what went wrong.
-\b \q{Log SSH packet data}. In this mode (which is only used by SSH
-connections), the SSH message packets sent over the encrypted
-connection are written to the log file. You might need this to debug
-a network-level problem, or more likely to send to the PuTTY authors
-as part of a bug report. \e{BE WARNED} that if you log in using a
-password, the password can appear in the log file; see
-\k{config-logssh} for options that may help to remove sensitive
-material from the log file before you send it to anyone else.
+\b \I{SSH packet log}\q{SSH packets}. In this mode (which is only used
+by SSH connections), the SSH message packets sent over the encrypted
+connection are written to the log file (as well as \i{Event Log}
+entries). You might need this to debug a network-level problem, or
+more likely to send to the PuTTY authors as part of a bug report.
+\e{BE WARNED} that if you log in using a password, the password can
+appear in the log file; see \k{config-logssh} for options that may
+help to remove sensitive material from the log file before you send it
+to anyone else.
+
+\b \q{SSH packets and raw data}. In this mode, as well as the
+decrypted packets (as in the previous mode), the \e{raw} (encrypted,
+compressed, etc) packets are \e{also} logged. This could be useful to
+diagnose corruption in transit. (The same caveats as the previous mode
+apply, of course.)
+
+Note that the non-SSH logging options (\q{Printable output} and
+\q{All session output}) only work with PuTTY proper; in programs
+without terminal emulation (such as Plink), they will have no effect,
+even if enabled via saved settings.
\S{config-logfilename} \q{Log file name}
automatic behaviour, but to ask the user every time the problem
comes up.
-\S{config-logflush} \q{Flush log file frequently}
+\S{config-logflush} \I{log file, flushing}\q{Flush log file frequently}
\cfg{winhelp-topic}{logging.flush}
(although it will of course be flushed when it is closed, for instance
at the end of a session).
-\S{config-logssh} Options specific to SSH packet logging
+\S{config-logssh} Options specific to \i{SSH packet log}ging
These options only apply if SSH packet data is being logged.
\cfg{winhelp-topic}{logging.ssh.omitpassword}
-When checked, password fields are removed from the log of transmitted
-packets. (This includes any user responses to challenge-response
-authentication methods such as \q{keyboard-interactive}.) This does
-not include X11 authentication data if using X11 forwarding.
+When checked, decrypted password fields are removed from the log of
+transmitted packets. (This includes any user responses to
+challenge-response authentication methods such as
+\q{keyboard-interactive}.) This does not include X11 authentication
+data if using X11 forwarding.
Note that this will only omit data that PuTTY \e{knows} to be a
password. However, if you start another login session within your
\cfg{winhelp-topic}{logging.ssh.omitdata}
-When checked, all \q{session data} is omitted; this is defined as data
-in terminal sessions and in forwarded channels (TCP, X11, and
-authentication agent). This will usually substantially reduce the size
-of the resulting log file.
+When checked, all decrypted \q{session data} is omitted; this is
+defined as data in terminal sessions and in forwarded channels (TCP,
+X11, and authentication agent). This will usually substantially reduce
+the size of the resulting log file.
This option is disabled by default.
\H{config-terminal} The Terminal panel
The Terminal configuration panel allows you to control the behaviour
-of PuTTY's terminal emulation.
+of PuTTY's \i{terminal emulation}.
\S{config-autowrap} \q{Auto wrap mode initially on}
\cfg{winhelp-topic}{terminal.autowrap}
-Auto wrap mode controls what happens when text printed in a PuTTY
+\ii{Auto wrap mode} controls what happens when text printed in a PuTTY
window reaches the right-hand edge of the window.
With auto wrap mode on, if a long line of text reaches the
find the screen scrolling up when it looks as if it shouldn't, you
could try turning this option off.
-Auto wrap mode can be turned on and off by control sequences sent by
+Auto wrap mode can be turned on and off by \i{control sequence}s sent by
the server. This configuration option controls the \e{default}
state, which will be restored when you reset the terminal (see
\k{reset-terminal}). However, if you modify this option in
\cfg{winhelp-topic}{terminal.decom}
-DEC Origin Mode is a minor option which controls how PuTTY
-interprets cursor-position control sequences sent by the server.
+\i{DEC Origin Mode} is a minor option which controls how PuTTY
+interprets cursor-position \i{control sequence}s sent by the server.
-The server can send a control sequence that restricts the scrolling
-region of the display. For example, in an editor, the server might
+The server can send a control sequence that restricts the \i{scrolling
+region} of the display. For example, in an editor, the server might
reserve a line at the top of the screen and a line at the bottom,
and might send a control sequence that causes scrolling operations
to affect only the remaining lines.
-With DEC Origin Mode on, cursor coordinates are counted from the top
+With DEC Origin Mode on, \i{cursor coordinates} are counted from the top
of the scrolling region. With it turned off, cursor coordinates are
counted from the top of the whole screen regardless of the scrolling
region.
\cfg{winhelp-topic}{terminal.lfhascr}
-Most servers send two control characters, CR and LF, to start a new
-line of the screen. The CR character makes the cursor return to the
+Most servers send two control characters, \i{CR} and \i{LF}, to start a
+\i{new line} of the screen. The CR character makes the cursor return to the
left-hand side of the screen. The LF character makes the cursor move
one line down (and might make the screen scroll).
Some servers only send LF, and expect the terminal to move the
cursor over to the left automatically. If you come across a server
-that does this, you will see a stepped effect on the screen, like
-this:
+that does this, you will see a \I{stair-stepping}stepped effect on the
+screen, like this:
\c First line of text
\c Second line
\c Second line
\c Third line
-\S{config-erase} \q{Use background colour to erase screen}
+\S{config-lfcr} \q{Implicit LF in every CR}
+
+\cfg{winhelp-topic}{terminal.crhaslf}
+
+Most servers send two control characters, \i{CR} and \i{LF}, to start a
+\i{new line} of the screen. The CR character makes the cursor return to the
+left-hand side of the screen. The LF character makes the cursor move
+one line down (and might make the screen scroll).
+
+Some servers only send CR, and so the newly
+written line is overwritten by the following line. This option causes
+a line feed so that all lines are displayed.
+
+\S{config-erase} \q{Use \i{background colour} to erase screen}
\cfg{winhelp-topic}{terminal.bce}
Not all terminals agree on what colour to turn the screen when the
-server sends a \q{clear screen} sequence. Some terminals believe the
+server sends a \q{\i{clear screen}} sequence. Some terminals believe the
screen should always be cleared to the \e{default} background
colour. Others believe the screen should be cleared to whatever the
server has selected as a background colour.
default background colour. With this option enabled, it is done in
the \e{current} background colour.
-Background-colour erase can be turned on and off by control
-sequences sent by the server. This configuration option controls the
+Background-colour erase can be turned on and off by \i{control
+sequences} sent by the server. This configuration option controls the
\e{default} state, which will be restored when you reset the
terminal (see \k{reset-terminal}). However, if you modify this
option in mid-session using \q{Change Settings}, it will take effect
immediately.
-\S{config-blink} \q{Enable blinking text}
+\S{config-blink} \q{Enable \i{blinking text}}
\cfg{winhelp-topic}{terminal.blink}
off completely.
When blinking text is disabled and the server attempts to make some
-text blink, PuTTY will instead display the text with a bolded
-background colour.
+text blink, PuTTY will instead display the text with a \I{background
+colour, bright}bolded background colour.
-Blinking text can be turned on and off by control sequences sent by
+Blinking text can be turned on and off by \i{control sequence}s sent by
the server. This configuration option controls the \e{default}
state, which will be restored when you reset the terminal (see
\k{reset-terminal}). However, if you modify this option in
mid-session using \q{Change Settings}, it will take effect
immediately.
-\S{config-answerback} \q{Answerback to ^E}
+\S{config-answerback} \q{\ii{Answerback} to ^E}
\cfg{winhelp-topic}{terminal.answerback}
This option controls what PuTTY will send back to the server if the
-server sends it the ^E enquiry character. Normally it just sends
+server sends it the ^E \i{enquiry character}. Normally it just sends
the string \q{PuTTY}.
If you accidentally write the contents of a binary file to your
Note that this is \e{not} the feature of PuTTY which the server will
typically use to determine your terminal type. That feature is the
-\q{Terminal-type string} in the Connection panel; see
+\q{\ii{Terminal-type} string} in the Connection panel; see
\k{config-termtype} for details.
You can include control characters in the answerback string using
\c{^C} notation. (Use \c{^~} to get a literal \c{^}.)
-\S{config-localecho} \q{Local echo}
+\S{config-localecho} \q{\ii{Local echo}}
\cfg{winhelp-topic}{terminal.localecho}
With local echo disabled, characters you type into the PuTTY window
are not echoed in the window \e{by PuTTY}. They are simply sent to
-the server. (The \e{server} might choose to echo them back to you;
-this can't be controlled from the PuTTY control panel.)
+the server. (The \e{server} might choose to \I{remote echo}echo them
+back to you; this can't be controlled from the PuTTY control panel.)
Some types of session need local echo, and many do not. In its
default mode, PuTTY will automatically attempt to deduce whether or
echo to be turned on, or force it to be turned off, instead of
relying on the automatic detection.
-\S{config-localedit} \q{Local line editing}
+\S{config-localedit} \q{\ii{Local line editing}}
\cfg{winhelp-topic}{terminal.localedit}
server will never see the mistake.
Since it is hard to edit a line locally without being able to see
-it, local line editing is mostly used in conjunction with local echo
+it, local line editing is mostly used in conjunction with \i{local echo}
(\k{config-localecho}). This makes it ideal for use in raw mode
-\#{FIXME} or when connecting to MUDs or talkers. (Although some more
+\#{FIXME} or when connecting to \i{MUD}s or \i{talker}s. (Although some more
advanced MUDs do occasionally turn local line editing on and turn
local echo off, in order to accept a password from the user.)
local line editing to be turned on, or force it to be turned off,
instead of relying on the automatic detection.
-\S{config-printing} Remote-controlled printing
+\S{config-printing} \ii{Remote-controlled printing}
\cfg{winhelp-topic}{terminal.printing}
\H{config-keyboard} The Keyboard panel
The Keyboard configuration panel allows you to control the behaviour
-of the keyboard in PuTTY.
+of the \i{keyboard} in PuTTY. The correct state for many of these
+settings depends on what the server to which PuTTY is connecting
+expects. With a \i{Unix} server, this is likely to depend on the
+\i\c{termcap} or \i\c{terminfo} entry it uses, which in turn is likely to
+be controlled by the \q{\ii{Terminal-type} string} setting in the Connection
+panel; see \k{config-termtype} for details. If none of the settings here
+seems to help, you may find \k{faq-keyboard} to be useful.
-\S{config-backspace} Changing the action of the Backspace key
+\S{config-backspace} Changing the action of the \ii{Backspace key}
\cfg{winhelp-topic}{keyboard.backspace}
Some terminals believe that the Backspace key should send the same
-thing to the server as Control-H (ASCII code 8). Other terminals
+thing to the server as \i{Control-H} (ASCII code 8). Other terminals
believe that the Backspace key should send ASCII code 127 (usually
-known as Control-?) so that it can be distinguished from Control-H.
+known as \i{Control-?}) so that it can be distinguished from Control-H.
This option allows you to choose which code PuTTY generates when you
press Backspace.
-If you are connecting to a Unix system, you will probably find that
-the Unix \c{stty} command lets you configure which the server
-expects to see, so you might not need to change which one PuTTY
+If you are connecting over SSH, PuTTY by default tells the server
+the value of this option (see \k{config-ttymodes}), so you may find
+that the Backspace key does the right thing either way. Similarly,
+if you are connecting to a \i{Unix} system, you will probably find that
+the Unix \i\c{stty} command lets you configure which the server
+expects to see, so again you might not need to change which one PuTTY
generates. On other systems, the server's expectation might be fixed
and you might have no choice but to configure PuTTY.
(Typing \i{Shift-Backspace} will cause PuTTY to send whichever code
isn't configured here as the default.)
-\S{config-homeend} Changing the action of the Home and End keys
+\S{config-homeend} Changing the action of the \i{Home and End keys}
\cfg{winhelp-topic}{keyboard.homeend}
-The Unix terminal emulator \c{rxvt} disagrees with the rest of the
+The Unix terminal emulator \i\c{rxvt} disagrees with the rest of the
world about what character sequences should be sent to the server by
the Home and End keys.
-\c{xterm}, and other terminals, send \c{ESC [1~} for the Home key,
+\i\c{xterm}, and other terminals, send \c{ESC [1~} for the Home key,
and \c{ESC [4~} for the End key. \c{rxvt} sends \c{ESC [H} for the
Home key and \c{ESC [Ow} for the End key.
If you find an application on which the Home and End keys aren't
working, you could try switching this option to see if it helps.
-\S{config-funkeys} Changing the action of the function keys and keypad
+\S{config-funkeys} Changing the action of the \i{function keys} and
+\i{keypad}
\cfg{winhelp-topic}{keyboard.funkeys}
\b In Linux mode, F6 to F12 behave just like the default mode, but
F1 to F5 generate \c{ESC [[A} through to \c{ESC [[E}. This mimics the
-Linux virtual console.
+\i{Linux virtual console}.
-\b In Xterm R6 mode, F5 to F12 behave like the default mode, but F1
+\b In \I{xterm}Xterm R6 mode, F5 to F12 behave like the default mode, but F1
to F4 generate \c{ESC OP} through to \c{ESC OS}, which are the
sequences produced by the top row of the \e{keypad} on Digital's
terminals.
-\b In VT400 mode, all the function keys behave like the default
+\b In \i{VT400} mode, all the function keys behave like the default
mode, but the actual top row of the numeric keypad generates \c{ESC
OP} through to \c{ESC OS}.
-\b In VT100+ mode, the function keys generate \c{ESC OP} through to
+\b In \i{VT100+} mode, the function keys generate \c{ESC OP} through to
\c{ESC O[}
-\b In SCO mode, the function keys F1 to F12 generate \c{ESC [M}
+\b In \i{SCO} mode, the function keys F1 to F12 generate \c{ESC [M}
through to \c{ESC [X}. Together with shift, they generate \c{ESC [Y}
through to \c{ESC [j}. With control they generate \c{ESC [k} through
to \c{ESC [v}, and with shift and control together they generate
If you don't know what any of this means, you probably don't need to
fiddle with it.
-\S{config-appcursor} Controlling Application Cursor Keys mode
+\S{config-appcursor} Controlling \i{Application Cursor Keys} mode
\cfg{winhelp-topic}{keyboard.appcursor}
the \q{Features} configuration panel; see
\k{config-features-application}.
-\S{config-appkeypad} Controlling Application Keypad mode
+\S{config-appkeypad} Controlling \i{Application Keypad} mode
\cfg{winhelp-topic}{keyboard.appkeypad}
behaviour of the numeric keypad.
In normal mode, the keypad behaves like a normal Windows keypad:
-with NumLock on, the number keys generate numbers, and with NumLock
+with \i{NumLock} on, the number keys generate numbers, and with NumLock
off they act like the arrow keys and Home, End etc.
In application mode, all the keypad keys send special control
\q{Features} configuration panel; see
\k{config-features-application}.
-\S{config-nethack} Using NetHack keypad mode
+\S{config-nethack} Using \i{NetHack keypad mode}
\cfg{winhelp-topic}{keyboard.nethack}
movement commands (\cw{hjklyubn}). The 5 key generates the \c{.}
command (do nothing).
-Better still, pressing Shift with the keypad keys generates the
-capital forms of the commands (\cw{HJKLYUBN}), which tells NetHack
-to keep moving you in the same direction until you encounter
-something interesting.
+In addition, pressing Shift or Ctrl with the keypad keys generate
+the Shift- or Ctrl-keys you would expect (e.g. keypad-7 generates
+\cq{y}, so Shift-keypad-7 generates \cq{Y} and Ctrl-keypad-7
+generates Ctrl-Y); these commands tell NetHack to keep moving you in
+the same direction until you encounter something interesting.
-For some reason, this feature only works properly when Num Lock is
+For some reason, this feature only works properly when \i{Num Lock} is
on. We don't know why.
-\S{config-compose} Enabling a DEC-like Compose key
+\S{config-compose} Enabling a DEC-like \ii{Compose key}
\cfg{winhelp-topic}{keyboard.compose}
DEC terminals have a Compose key, which provides an easy-to-remember
-way of typing accented characters. You press Compose and then type
+way of typing \i{accented characters}. You press Compose and then type
two more characters. The two characters are \q{combined} to produce
an accented character. The choices of character are designed to be
easy to remember; for example, composing \q{e} and \q{`} produces
the \q{\u00e8{e-grave}} character.
-If your keyboard has a Windows Application key, it acts as a Compose
-key in PuTTY. Alternatively, if you enable the \q{AltGr acts as
+If your keyboard has a Windows \i{Application key}, it acts as a Compose
+key in PuTTY. Alternatively, if you enable the \q{\i{AltGr} acts as
Compose key} option, the AltGr key will become a Compose key.
-\S{config-ctrlalt} \q{Control-Alt is different from AltGr}
+\S{config-ctrlalt} \q{Control-Alt is different from \i{AltGr}}
\cfg{winhelp-topic}{keyboard.ctrlalt}
\H{config-bell} The Bell panel
-The Bell panel controls the terminal bell feature: the server's
+The Bell panel controls the \i{terminal bell} feature: the server's
ability to cause PuTTY to beep at you.
In the default configuration, when the server sends the character
-with ASCII code 7 (Control-G), PuTTY will play the Windows Default
-Beep sound. This is not always what you want the terminal bell
+with ASCII code 7 (Control-G), PuTTY will play the \i{Windows Default
+Beep} sound. This is not always what you want the terminal bell
feature to do; the Bell panel allows you to configure alternative
actions.
This control allows you to select various different actions to occur
on a terminal bell:
-\b Selecting \q{None} disables the bell completely. In this mode,
-the server can send as many Control-G characters as it likes and
-nothing at all will happen.
+\b Selecting \q{None} \I{terminal bell, disabling}disables the bell
+completely. In this mode, the server can send as many Control-G
+characters as it likes and nothing at all will happen.
\b \q{Make default system alert sound} is the default setting. It
causes the Windows \q{Default Beep} sound to be played. To change
what this sound is, or to test it if nothing seems to be happening,
use the Sound configurer in the Windows Control Panel.
-\b \q{Visual bell} is a silent alternative to a beeping computer. In
+\b \q{\ii{Visual bell}} is a silent alternative to a beeping computer. In
this mode, when the server sends a Control-G, the whole PuTTY window
will flash white for a fraction of a second.
-\b \q{Beep using the PC speaker} is self-explanatory.
+\b \q{Beep using the \i{PC speaker}} is self-explanatory.
-\b \q{Play a custom sound file} allows you to specify a particular
+\b \q{Play a custom \i{sound file}} allows you to specify a particular
sound file to be used by PuTTY alone, or even by a particular
individual PuTTY session. This allows you to distinguish your PuTTY
beeps from any other beeps on the system. If you select this option,
you will also need to enter the name of your sound file in the edit
control \q{Custom sound file to play as a bell}.
-\S{config-belltaskbar} \q{Taskbar/caption indication on bell}
+\S{config-belltaskbar} \q{\ii{Taskbar}/\I{window caption}caption
+indication on bell}
\cfg{winhelp-topic}{bell.taskbar}
\q{Flashing} is even more eye-catching: the Taskbar entry will
continuously flash on and off until you select the window.
-\S{config-bellovl} \q{Control the bell overload behaviour}
+\S{config-bellovl} \q{Control the \i{bell overload} behaviour}
\cfg{winhelp-topic}{bell.overload}
beeping, PuTTY includes a bell overload management feature. In the
default configuration, receiving more than five bell characters in a
two-second period will cause the overload feature to activate. Once
-the overload feature is active, further bells will have no effect at
-all, so the rest of your binary file will be sent to the screen in
-silence. After a period of five seconds during which no further
-bells are received, the overload feature will turn itself off again
-and bells will be re-enabled.
+the overload feature is active, further bells will \I{terminal bell,
+disabling} have no effect at all, so the rest of your binary file
+will be sent to the screen in silence. After a period of five seconds
+during which no further bells are received, the overload feature will
+turn itself off again and bells will be re-enabled.
If you want this feature completely disabled, you can turn it off
using the checkbox \q{Bell is temporarily disabled when over-used}.
\H{config-features} The Features panel
-PuTTY's terminal emulation is very highly featured, and can do a lot
+PuTTY's \i{terminal emulation} is very highly featured, and can do a lot
of things under remote server control. Some of these features can
cause problems due to buggy or strangely configured server
applications.
\cfg{winhelp-topic}{features.application}
-Application keypad mode (see \k{config-appkeypad}) and application
+\I{Application Keypad}Application keypad mode (see
+\k{config-appkeypad}) and \I{Application Cursor Keys}application
cursor keys mode (see \k{config-appcursor}) alter the behaviour of
the keypad and cursor keys. Some applications enable these modes but
then do not deal correctly with the modified keys. You can force
these modes to be permanently disabled no matter what the server
tries to do.
-\S{config-features-mouse} Disabling \cw{xterm}-style mouse reporting
+\S{config-features-mouse} Disabling \cw{xterm}-style \i{mouse reporting}
\cfg{winhelp-topic}{features.mouse}
-PuTTY allows the server to send control codes that let it take over
-the mouse and use it for purposes other than copy and paste.
+PuTTY allows the server to send \i{control codes} that let it take over
+the mouse and use it for purposes other than \i{copy and paste}.
Applications which use this feature include the text-mode web
-browser \c{links}, the Usenet newsreader \c{trn} version 4, and the
-file manager \c{mc} (Midnight Commander).
+browser \i\c{links}, the Usenet newsreader \i\c{trn} version 4, and the
+file manager \i\c{mc} (Midnight Commander).
If you find this feature inconvenient, you can disable it using the
\q{Disable xterm-style mouse reporting} control. With this box
while you select and paste, unless you have deliberately turned this
feature off (see \k{config-mouseshift}).
-\S{config-features-resize} Disabling remote terminal resizing
+\S{config-features-resize} Disabling remote \i{terminal resizing}
\cfg{winhelp-topic}{features.resize}
this unexpectedly or inconveniently, you can tell PuTTY not to
respond to those server commands.
-\S{config-features-altscreen} Disabling switching to the alternate screen
+\S{config-features-altscreen} Disabling switching to the \i{alternate screen}
\cfg{winhelp-topic}{features.altscreen}
run in the same screen as the rest of your terminal activity, you
can disable the alternate screen feature completely.
-\S{config-features-retitle} Disabling remote window title changing
+\S{config-features-retitle} Disabling remote \i{window title} changing
\cfg{winhelp-topic}{features.retitle}
unexpectedly or inconveniently, you can tell PuTTY not to respond to
those server commands.
-\S{config-features-qtitle} Disabling remote window title querying
+\S{config-features-qtitle} Response to remote \i{window title} querying
\cfg{winhelp-topic}{features.qtitle}
applications to find out the local window title. This feature is
disabled by default, but you can turn it on if you really want it.
-NOTE that this feature is a \e{potential security hazard}. If a
+NOTE that this feature is a \e{potential \i{security hazard}}. If a
malicious application can write data to your terminal (for example,
if you merely \c{cat} a file owned by someone else on the server
machine), it can change your window title (unless you have disabled
typed at the keyboard. This allows an attacker to fake keypresses
and potentially cause your server-side applications to do things you
didn't want. Therefore this feature is disabled by default, and we
-recommend you do not turn it on unless you \e{really} know what you
-are doing.
+recommend you do not set it to \q{Window title} unless you \e{really}
+know what you are doing.
+
+There are three settings for this option:
+
+\dt \q{None}
+
+\dd PuTTY makes no response whatsoever to the relevant escape
+sequence. This may upset server-side software that is expecting some
+sort of response.
+
+\dt \q{Empty string}
+
+\dd PuTTY makes a well-formed response, but leaves it blank. Thus,
+server-side software that expects a response is kept happy, but an
+attacker cannot influence the response string. This is probably the
+setting you want if you have no better ideas.
-\S{config-features-dbackspace} Disabling destructive backspace
+\dt \q{Window title}
+
+\dd PuTTY responds with the actual window title. This is dangerous for
+the reasons described above.
+
+\S{config-features-dbackspace} Disabling \i{destructive backspace}
\cfg{winhelp-topic}{features.dbackspace}
configure character 127 to perform a normal backspace (without
deleting a character) instead.
-\S{config-features-charset} Disabling remote character set
+\S{config-features-charset} Disabling remote \i{character set}
configuration
\cfg{winhelp-topic}{features.charset}
PuTTY has the ability to change its character set configuration in
response to commands from the server. Some programs send these
-commands unexpectedly or inconveniently. In particular, BitchX (an
+commands unexpectedly or inconveniently. In particular, \i{BitchX} (an
IRC client) seems to have a habit of reconfiguring the character set
to something other than the user intended.
expect them to, particularly if you're running BitchX, you could try
disabling the remote character set configuration commands.
-\S{config-features-shaping} Disabling Arabic text shaping
+\S{config-features-shaping} Disabling \i{Arabic text shaping}
\cfg{winhelp-topic}{features.arabicshaping}
PuTTY supports shaping of Arabic text, which means that if your
-server sends text written in the basic Unicode Arabic alphabet then
+server sends text written in the basic \i{Unicode} Arabic alphabet then
it will convert it to the correct display forms before printing it
on the screen.
to happen (especially if you are not an Arabic speaker and you
unexpectedly find yourself dealing with Arabic text files in
applications which are not Arabic-aware), you might find that the
-display becomes corrupted. By ticking this box, you can disable
+\i{display becomes corrupted}. By ticking this box, you can disable
Arabic text shaping so that PuTTY displays precisely the characters
it is told to display.
You may also find you need to disable bidirectional text display;
see \k{config-features-bidi}.
-\S{config-features-bidi} Disabling bidirectional text display
+\S{config-features-bidi} Disabling \i{bidirectional text} display
\cfg{winhelp-topic}{features.bidi}
PuTTY supports bidirectional text display, which means that if your
server sends text written in a language which is usually displayed
-from right to left (such as Arabic or Hebrew) then PuTTY will
+from right to left (such as \i{Arabic} or \i{Hebrew}) then PuTTY will
automatically flip it round so that it is displayed in the right
direction on the screen.
to happen (especially if you are not an Arabic speaker and you
unexpectedly find yourself dealing with Arabic text files in
applications which are not Arabic-aware), you might find that the
-display becomes corrupted. By ticking this box, you can disable
+\i{display becomes corrupted}. By ticking this box, you can disable
bidirectional text display, so that PuTTY displays text from left to
right in all situations.
\H{config-window} The Window panel
The Window configuration panel allows you to control aspects of the
-PuTTY window.
+\i{PuTTY window}.
-\S{config-winsize} Setting the size of the PuTTY window
+\S{config-winsize} Setting the \I{window size}size of the PuTTY window
\cfg{winhelp-topic}{window.size}
-The \q{Rows} and \q{Columns} boxes let you set the PuTTY window to a
-precise size. Of course you can also drag the window to a new size
-while a session is running.
+The \q{\ii{Columns}} and \q{\ii{Rows}} boxes let you set the PuTTY
+window to a precise size. Of course you can also \I{window resizing}drag
+the window to a new size while a session is running.
\S{config-winsizelock} What to do when the window is resized
\cfg{winhelp-topic}{window.resize}
These options allow you to control what happens when the user tries
-to resize the PuTTY window using its window furniture.
+to \I{window resizing}resize the PuTTY window using its window furniture.
There are four options here:
change. (This is the default.)
\b \q{Change the size of the font}: the number of rows and columns in
-the terminal will stay the same, and the font size will change.
+the terminal will stay the same, and the \i{font size} will change.
\b \q{Change font size when maximised}: when the window is resized,
the number of rows and columns will change, \e{except} when the window
-is maximised (or restored), when the font size will change.
+is \i{maximise}d (or restored), when the font size will change. (In
+this mode, holding down the Alt key while resizing will also cause the
+font size to change.)
\b \q{Forbid resizing completely}: the terminal will refuse to be
resized at all.
-\S{config-scrollback} Controlling scrollback
+\S{config-scrollback} Controlling \i{scrollback}
\cfg{winhelp-topic}{window.scrollback}
The \q{Lines of scrollback} box lets you configure how many lines of
text PuTTY keeps. The \q{Display scrollbar} options allow you to
-hide the scrollbar (although you can still view the scrollback using
+hide the \i{scrollbar} (although you can still view the scrollback using
the keyboard as described in \k{using-scrollback}). You can separately
-configure whether the scrollbar is shown in full-screen mode and in
+configure whether the scrollbar is shown in \i{full-screen} mode and in
normal modes.
If you are viewing part of the scrollback when the server sends more
clears the screen, so that your scrollback will contain a better
record of what was on your screen in the past.
-If the application switches to the alternate screen (see
+If the application switches to the \i{alternate screen} (see
\k{config-features-altscreen} for more about this), then the
contents of the primary screen will be visible in the scrollback
until the application switches back again.
\H{config-appearance} The Appearance panel
The Appearance configuration panel allows you to control aspects of
-the appearance of PuTTY's window.
+the appearance of \I{PuTTY window}PuTTY's window.
-\S{config-cursor} Controlling the appearance of the cursor
+\S{config-cursor} Controlling the appearance of the \i{cursor}
\cfg{winhelp-topic}{appearance.cursor}
empty box when the window loses focus; an underline or a vertical
line becomes dotted.
-The \q{Cursor blinks} option makes the cursor blink on and off. This
+The \q{\ii{Cursor blinks}} option makes the cursor blink on and off. This
works in any of the cursor modes.
-\S{config-font} Controlling the font used in the terminal window
+\S{config-font} Controlling the \i{font} used in the terminal window
\cfg{winhelp-topic}{appearance.font}
-This option allows you to choose what font, in what size, the PuTTY
-terminal window uses to display the text in the session. You will be
-offered a choice from all the fixed-width fonts installed on the
-system. (VT100-style terminal handling can only deal with fixed-
-width fonts.)
+This option allows you to choose what font, in what \I{font size}size,
+the PuTTY terminal window uses to display the text in the session.
+
+By default, you will be offered a choice from all the fixed-width
+fonts installed on the system, since VT100-style terminal handling
+expects a fixed-width font. If you tick the box marked \q{Allow
+selection of variable-pitch fonts}, however, PuTTY will offer
+variable-width fonts as well: if you select one of these, the font
+will be coerced into fixed-size character cells, which will probably
+not look very good (but can work OK with some fonts).
-\S{config-mouseptr} \q{Hide mouse pointer when typing in window}
+\S{config-mouseptr} \q{Hide \i{mouse pointer} when typing in window}
\cfg{winhelp-topic}{appearance.hidemouse}
This option is disabled by default, so the mouse pointer remains
visible at all times.
-\S{config-winborder} Controlling the window border
+\S{config-winborder} Controlling the \i{window border}
\cfg{winhelp-topic}{appearance.border}
\H{config-behaviour} The Behaviour panel
The Behaviour configuration panel allows you to control aspects of
-the behaviour of PuTTY's window.
+the behaviour of \I{PuTTY window}PuTTY's window.
-\S{config-title} Controlling the window title
+\S{config-title} Controlling the \i{window title}
\cfg{winhelp-topic}{appearance.title}
The \q{Window title} edit box allows you to set the title of the
-PuTTY window. By default the window title will contain the host name
+PuTTY window. By default the window title will contain the \i{host name}
followed by \q{PuTTY}, for example \c{server1.example.com - PuTTY}.
If you want a different window title, this is where to set it.
-PuTTY allows the server to send \c{xterm} control sequences which
+PuTTY allows the server to send \c{xterm} \i{control sequence}s which
modify the title of the window in mid-session (unless this is disabled -
see \k{config-features-retitle}); the title string set here
is therefore only the \e{initial} window title.
-As well as the \e{window} title, there is also an
-\c{xterm} sequence to modify the title of the window's \e{icon}.
+As well as the \e{window} title, there is also an \c{xterm}
+sequence to modify the \I{icon title}title of the window's \e{icon}.
This makes sense in a windowing system where the window becomes an
icon when minimised, such as Windows 3.1 or most X Window System
setups; but in the Windows 95-like user interface it isn't as
By default, PuTTY only uses the server-supplied \e{window} title, and
ignores the icon title entirely. If for some reason you want to see
both titles, check the box marked \q{Separate window and icon titles}.
-If you do this, PuTTY's window title and Taskbar caption will
-change into the server-supplied icon title if you minimise the PuTTY
+If you do this, PuTTY's window title and Taskbar \I{window caption}caption will
+change into the server-supplied icon title if you \i{minimise} the PuTTY
window, and change back to the server-supplied window title if you
restore it. (If the server has not bothered to supply a window or
icon title, none of this will happen.)
-\S{config-warnonclose} \q{Warn before closing window}
+\S{config-warnonclose} \q{Warn before \i{closing window}}
\cfg{winhelp-topic}{behaviour.closewarn}
-If you press the Close button in a PuTTY window that contains a
+If you press the \i{Close button} in a PuTTY window that contains a
running session, PuTTY will put up a warning window asking if you
really meant to close the window. A window whose session has already
terminated can always be closed without a warning.
If you want to be able to close a window quickly, you can disable
the \q{Warn before closing window} option.
-\S{config-altf4} \q{Window closes on ALT-F4}
+\S{config-altf4} \q{Window closes on \i{ALT-F4}}
\cfg{winhelp-topic}{behaviour.altf4}
-By default, pressing ALT-F4 causes the window to close (or a warning
-box to appear; see \k{config-warnonclose}). If you disable the
-\q{Window closes on ALT-F4} option, then pressing ALT-F4 will simply
-send a key sequence to the server.
+By default, pressing ALT-F4 causes the \I{closing window}window to
+close (or a warning box to appear; see \k{config-warnonclose}). If you
+disable the \q{Window closes on ALT-F4} option, then pressing ALT-F4
+will simply send a key sequence to the server.
-\S{config-altspace} \q{System menu appears on ALT-Space}
+\S{config-altspace} \q{\ii{System menu} appears on \i{ALT-Space}}
\cfg{winhelp-topic}{behaviour.altspace}
disabled, then pressing ALT-Space will just send \c{ESC SPACE} to
the server.
-Some accessibility programs for Windows may need this option
+Some \i{accessibility} programs for Windows may need this option
enabling to be able to control PuTTY's window successfully. For
-instance, Dragon NaturallySpeaking requires it both to open the
+instance, \i{Dragon NaturallySpeaking} requires it both to open the
system menu via voice, and to close, minimise, maximise and restore
the window.
-\S{config-altonly} \q{System menu appears on Alt alone}
+\S{config-altonly} \q{\ii{System menu} appears on \i{Alt} alone}
\cfg{winhelp-topic}{behaviour.altonly}
corner. If it is disabled, then pressing and releasing ALT will have
no effect.
-\S{config-alwaysontop} \q{Ensure window is always on top}
+\S{config-alwaysontop} \q{Ensure window is \i{always on top}}
\cfg{winhelp-topic}{behaviour.alwaysontop}
If this option is enabled, the PuTTY window will stay on top of all
other windows.
-\S{config-fullscreen} \q{Full screen on Alt-Enter}
+\S{config-fullscreen} \q{\ii{Full screen} on Alt-Enter}
\cfg{winhelp-topic}{behaviour.altenter}
PuTTY window to become full-screen. Pressing Alt-Enter again will
restore the previous window size.
-The full-screen feature is also available from the System menu, even
+The full-screen feature is also available from the \ii{System menu}, even
when it is configured not to be available on the Alt-Enter key. See
\k{using-fullscreen}.
\H{config-translation} The Translation panel
The Translation configuration panel allows you to control the
-translation between the character set understood by the server and
+translation between the \i{character set} understood by the server and
the character set understood by PuTTY.
\S{config-charset} Controlling character set translation
During an interactive session, PuTTY receives a stream of 8-bit
bytes from the server, and in order to display them on the screen it
-needs to know what character set to interpret them in.
+needs to know what character set to interpret them in. Similarly,
+PuTTY needs to know how to translate your keystrokes into the encoding
+the server expects. Unfortunately, there is no satisfactory
+mechanism for PuTTY and the server to communicate this information,
+so it must usually be manually configured.
-There are a lot of character sets to choose from. The \q{Received
-data assumed to be in which character set} option lets you select
-one. By default PuTTY will attempt to choose a character set that is
-right for your locale as reported by Windows; if it gets it wrong,
-you can select a different one using this control.
+There are a lot of character sets to choose from. The \q{Remote
+character set} option lets you select one.
-A few notable character sets are:
+By default PuTTY will use the \i{UTF-8} encoding of \i{Unicode}, which
+can represent pretty much any character; data coming from the server
+is interpreted as UTF-8, and keystrokes are sent UTF-8 encoded. This
+is what most modern distributions of Linux will expect by default.
+However, if this is wrong for your server, you can select a different
+character set using this control.
-\b The ISO-8859 series are all standard character sets that include
+A few other notable character sets are:
+
+\b The \i{ISO-8859} series are all standard character sets that include
various accented characters appropriate for different sets of
languages.
-\b The Win125x series are defined by Microsoft, for similar
+\b The \i{Win125x} series are defined by Microsoft, for similar
purposes. In particular Win1252 is almost equivalent to ISO-8859-1,
but contains a few extra characters such as matched quotes and the
Euro symbol.
\b If you want the old IBM PC character set with block graphics and
-line-drawing characters, you can select \q{CP437}.
-
-\b PuTTY also supports Unicode mode, in which the data coming from
-the server is interpreted as being in the UTF-8 encoding of Unicode.
-If you select \q{UTF-8} as a character set you can use this mode.
-Not all server-side applications will support it.
+line-drawing characters, you can select \q{\i{CP437}}.
-If you need support for a numeric code page which is not listed in
+If you need support for a numeric \i{code page} which is not listed in
the drop-down list, such as code page 866, then you can try entering
-its name manually (\c{CP866} for example) in the list box. If the
+its name manually (\c{\i{CP866}} for example) in the list box. If the
underlying version of Windows has the appropriate translation table
installed, PuTTY will use it.
-\S{config-cyr} \q{Caps Lock acts as Cyrillic switch}
+\S{config-cjk-ambig-wide} \q{Treat \i{CJK} ambiguous characters as wide}
+
+\cfg{winhelp-topic}{translation.cjkambigwide}
+
+There are \I{East Asian Ambiguous characters}some Unicode characters
+whose \I{character width}width is not well-defined. In most contexts, such
+characters should be treated as single-width for the purposes of \I{wrapping,
+terminal}wrapping and so on; however, in some CJK contexts, they are better
+treated as double-width for historical reasons, and some server-side
+applications may expect them to be displayed as such. Setting this option
+will cause PuTTY to take the double-width interpretation.
+
+If you use legacy CJK applications, and you find your lines are
+wrapping in the wrong places, or you are having other display
+problems, you might want to play with this setting.
+
+This option only has any effect in \i{UTF-8} mode (see \k{config-charset}).
+
+\S{config-cyr} \q{\i{Caps Lock} acts as \i{Cyrillic} switch}
\cfg{winhelp-topic}{translation.cyrillic}
This feature allows you to switch between a US/UK keyboard layout
and a Cyrillic keyboard layout by using the Caps Lock key, if you
-need to type (for example) Russian and English side by side in the
+need to type (for example) \i{Russian} and English side by side in the
same document.
Currently this feature is not expected to work properly if your
native keyboard layout is not US or UK.
-\S{config-linedraw} Controlling display of line drawing characters
+\S{config-linedraw} Controlling display of \i{line-drawing characters}
\cfg{winhelp-topic}{translation.linedraw}
-VT100-series terminals allow the server to send control sequences that
+VT100-series terminals allow the server to send \i{control sequence}s that
shift temporarily into a separate character set for drawing simple
lines and boxes. However, there are a variety of ways in which PuTTY
can attempt to find appropriate characters, and the right one to use
-depends on the locally configured font. In general you should probably
+depends on the locally configured \i{font}. In general you should probably
try lots of options until you find one that your particular font
supports.
\b \q{Use Unicode line drawing code points} tries to use the box
-characters that are present in Unicode. For good Unicode-supporting
+characters that are present in \i{Unicode}. For good Unicode-supporting
fonts this is probably the most reliable and functional option.
\b \q{Poor man's line drawing} assumes that the font \e{cannot}
\b \q{Use font in OEM mode only} is more reliable than that, but can
miss out other characters from the main character set.
-\S{config-linedrawpaste} Controlling copy and paste of line drawing
+\S{config-linedrawpaste} Controlling \i{copy and paste} of line drawing
characters
\cfg{winhelp-topic}{selection.linedraw}
By default, when you copy and paste a piece of the PuTTY screen that
contains VT100 line and box drawing characters, PuTTY will paste
-them in the form they appear on the screen: either Unicode line
+them in the form they appear on the screen: either \i{Unicode} line
drawing code points, or the \q{poor man's} line-drawing characters
\c{+}, \c{-} and \c{|}. The checkbox \q{Copy and paste VT100 line
drawing chars as lqqqk} disables this feature, so line-drawing
-characters will be pasted as the ASCII characters that were printed
+characters will be pasted as the \i{ASCII} characters that were printed
to produce them. This will typically mean they come out mostly as
\c{q} and \c{x}, with a scattering of \c{jklmntuvw} at the corners.
This might be useful if you were trying to recreate the same box
\H{config-selection} The Selection panel
-The Selection panel allows you to control the way copy and paste
+The Selection panel allows you to control the way \i{copy and paste}
work in the PuTTY window.
-\S{config-rtfpaste} Pasting in Rich Text Format
+\S{config-rtfpaste} Pasting in \i{Rich Text Format}
\cfg{winhelp-topic}{selection.rtf}
If you enable \q{Paste to clipboard in RTF as well as plain text},
PuTTY will write formatting information to the clipboard as well as
-the actual text you copy. Currently the only effect of this will be
+the actual text you copy. The effect of this is
that if you paste into (say) a word processor, the text will appear
-in the word processor in the same font PuTTY was using to display
-it. In future it is likely that other formatting information (bold,
-underline, colours) will be copied as well.
+in the word processor in the same \i{font}, \i{colour}, and style
+(e.g. bold, underline) PuTTY was using to display it.
This option can easily be inconvenient, so by default it is
disabled.
PuTTY's copy and paste mechanism is by default modelled on the Unix
\c{xterm} application. The X Window System uses a three-button mouse,
-and the convention is that the left button selects, the right button
-extends an existing selection, and the middle button pastes.
+and the convention is that the \i{left button} \I{selecting text}selects,
+the \i{right button} extends an existing selection, and the
+\i{middle button} pastes.
Windows often only has two mouse buttons, so in PuTTY's default
configuration (\q{Compromise}), the \e{right} button pastes, and the
-\e{middle} button (if you have one) extends a selection.
+\e{middle} button (if you have one) \I{adjusting a selection}extends
+a selection.
-If you have a three-button mouse and you are already used to the
+If you have a \i{three-button mouse} and you are already used to the
\c{xterm} arrangement, you can select it using the \q{Action of
mouse buttons} control.
Alternatively, with the \q{Windows} option selected, the middle
-button extends, and the right button brings up a context menu (on
+button extends, and the right button brings up a \i{context menu} (on
which one of the options is \q{Paste}). (This context menu is always
available by holding down Ctrl and right-clicking, regardless of the
setting of this option.)
\cfg{winhelp-topic}{selection.shiftdrag}
-PuTTY allows the server to send control codes that let it take over
-the mouse and use it for purposes other than copy and paste.
+PuTTY allows the server to send \i{control codes} that let it
+\I{mouse reporting}take over the mouse and use it for purposes other
+than \i{copy and paste}.
Applications which use this feature include the text-mode web
browser \c{links}, the Usenet newsreader \c{trn} version 4, and the
file manager \c{mc} (Midnight Commander).
Normally, you have to hold down Alt while dragging the mouse to
select a rectangular block. Using the \q{Default selection mode}
-control, you can set rectangular selection as the default, and then
+control, you can set \i{rectangular selection} as the default, and then
you have to hold down Alt to get the \e{normal} behaviour.
-\S{config-charclasses} Configuring word-by-word selection
+\S{config-charclasses} Configuring \i{word-by-word selection}
\cfg{winhelp-topic}{selection.charclasses}
PuTTY will select a word at a time in the terminal window if you
-double-click to begin the drag. This panel allows you to control
+\i{double-click} to begin the drag. This panel allows you to control
precisely what is considered to be a word.
Each character is given a \e{class}, which is a small number
assignment of characters to classes, you can modify the word-by-word
selection behaviour.
-In the default configuration, the character classes are:
+In the default configuration, the \i{character classes} are:
-\b Class 0 contains white space and control characters.
+\b Class 0 contains \i{white space} and control characters.
-\b Class 1 contains most punctuation.
+\b Class 1 contains most \i{punctuation}.
\b Class 2 contains letters, numbers and a few pieces of punctuation
(the double quote, minus sign, period, forward slash and
This mechanism currently only covers ASCII characters, because it
isn't feasible to expand the list to cover the whole of Unicode.
-Character class definitions can be modified by control sequences
+Character class definitions can be modified by \i{control sequence}s
sent by the server. This configuration option controls the
\e{default} state, which will be restored when you reset the
terminal (see \k{reset-terminal}). However, if you modify this
\H{config-colours} The Colours panel
-The Colours panel allows you to control PuTTY's use of colour.
+The Colours panel allows you to control PuTTY's use of \i{colour}.
-\S{config-ansicolour} \q{Allow terminal to specify ANSI colours}
+\S{config-ansicolour} \q{Allow terminal to specify \i{ANSI colours}}
\cfg{winhelp-topic}{colours.ansi}
This option is enabled by default. If it is disabled, PuTTY will
-ignore any control sequences sent by the server to request coloured
+ignore any \i{control sequence}s sent by the server to request coloured
text.
If you have a particularly garish application, you might want to
turn this option off and make PuTTY only use the default foreground
and background colours.
-\S{config-xtermcolour} \q{Allow terminal to use xterm 256-colour mode}
+\S{config-xtermcolour} \q{Allow terminal to use xterm \i{256-colour mode}}
\cfg{winhelp-topic}{colours.xterm256}
If you have an application which is supposed to use 256-colour mode
and it isn't working, you may find you need to tell your server that
your terminal supports 256 colours. On Unix, you do this by ensuring
-that the setting of \cw{TERM} describes a 256-colour-capable
+that the setting of \i\cw{TERM} describes a 256-colour-capable
terminal. You can check this using a command such as \c{infocmp}:
\c $ infocmp | grep colors
change your terminal setting. On modern Linux machines, you could
try \cq{xterm-256color}.
-\S{config-boldcolour} \q{Bolded text is a different colour}
+\S{config-boldcolour} \q{Indicate bolded text by changing}
\cfg{winhelp-topic}{colours.bold}
-When the server sends a control sequence indicating that some text
-should be displayed in bold, PuTTY can handle this two ways. It can
-either change the font for a bold version, or use the same font in a
-brighter colour. This control lets you choose which.
+When the server sends a \i{control sequence} indicating that some text
+should be displayed in \i{bold}, PuTTY can handle this in several
+ways. It can either change the \i{font} for a bold version, or use the
+same font in a brighter colour, or it can do both (brighten the colour
+\e{and} embolden the font). This control lets you choose which.
-By default the box is checked, so non-bold text is displayed in
-light grey and bold text is displayed in bright white (and similarly
-in other colours). If you uncheck the box, bold and non-bold text
-will be displayed in the same colour, and instead the font will
-change to indicate the difference.
+By default bold is indicated by colour, so non-bold text is displayed
+in light grey and bold text is displayed in bright white (and
+similarly in other colours). If you change the setting to \q{The font}
+box, bold and non-bold text will be displayed in the same colour, and
+instead the font will change to indicate the difference. If you select
+\q{Both}, the font and the colour will both change.
-\S{config-logpalette} \q{Attempt to use logical palettes}
+\S{config-logpalette} \q{Attempt to use \i{logical palettes}}
\cfg{winhelp-topic}{colours.logpal}
Logical palettes are a mechanism by which a Windows application
-running on an 8-bit colour display can select precisely the colours
+running on an \i{8-bit colour} display can select precisely the colours
it wants instead of going with the Windows standard defaults.
If you are not getting the colours you ask for on an 8-bit display,
you can try enabling this option. However, be warned that it's never
worked very well.
-\S{config-syscolour} \q{Use system colours}
+\S{config-syscolour} \q{Use \i{system colours}}
\cfg{winhelp-topic}{colours.system}
Enabling this option will cause PuTTY to ignore the configured colours
-for \q{Default Background/Foreground} and \q{Cursor Colour/Text} (see
+for \I{default background}\I{default foreground}\q{Default
+Background/Foreground} and \I{cursor colour}\q{Cursor Colour/Text} (see
\k{config-colourcfg}), instead going with the system-wide defaults.
-Note that non-bold and bold text will be the same colour if this
+Note that non-bold and \i{bold text} will be the same colour if this
option is enabled. You might want to change to indicating bold text
by font changes (see \k{config-boldcolour}).
-\S{config-colourcfg} Adjusting the colours in the terminal window
+\S{config-colourcfg} Adjusting the colours in the \i{terminal window}
\cfg{winhelp-topic}{colours.config}
The main colour control allows you to specify exactly what colours
things should be displayed in. To modify one of the PuTTY colours,
-use the list box to select which colour you want to modify. The RGB
-values for that colour will appear on the right-hand side of the
+use the list box to select which colour you want to modify. The \i{RGB
+values} for that colour will appear on the right-hand side of the
list box. Now, if you press the \q{Modify} button, you will be
presented with a colour selector, in which you can choose a new
-colour to go in place of the old one.
-
-PuTTY allows you to set the cursor colour, the default foreground
-and background, and the precise shades of all the ANSI configurable
-colours (black, red, green, yellow, blue, magenta, cyan, and white).
-You can also modify the precise shades used for the bold versions of
-these colours; these are used to display bold text if you have
-selected \q{Bolded text is a different colour}, and can also be used
-if the server asks specifically to use them. (Note that \q{Default
+colour to go in place of the old one. (You may also edit the RGB
+values directly in the edit boxes, if you wish; each value is an
+integer from 0 to 255.)
+
+PuTTY allows you to set the \i{cursor colour}, the \i{default foreground}
+and \I{default background}background, and the precise shades of all the
+\I{ANSI colours}ANSI configurable colours (black, red, green, yellow, blue,
+magenta, cyan, and white). You can also modify the precise shades used for
+the \i{bold} versions of these colours; these are used to display bold text
+if you have selected \q{Bolded text is a different colour}, and can also be
+used if the server asks specifically to use them. (Note that \q{Default
Bold Background} is \e{not} the background colour used for bold text;
it is only used if the server specifically asks for a bold
background.)
\H{config-connection} The Connection panel
The Connection panel allows you to configure options that apply to
-more than one type of connection.
+more than one type of \i{connection}.
-\S{config-keepalive} Using keepalives to prevent disconnection
+\S{config-keepalive} Using \i{keepalives} to prevent disconnection
\cfg{winhelp-topic}{connection.keepalive}
\q{Connection reset by peer}) after they have been idle for a while,
you might want to try using this option.
-Some network routers and firewalls need to keep track of all
+Some network \i{routers} and \i{firewalls} need to keep track of all
connections through them. Usually, these firewalls will assume a
connection is dead if no data is transferred in either direction
after a certain time interval. This can cause PuTTY sessions to be
The keepalive option (\q{Seconds between keepalives}) allows you to
configure PuTTY to send data through the session at regular
intervals, in a way that does not disrupt the actual terminal
-session. If you find your firewall is cutting idle connections off,
+session. If you find your firewall is cutting \i{idle connections} off,
you can try entering a non-zero value in this field. The value is
measured in seconds; so, for example, if your firewall cuts
connections off after ten minutes then you might want to enter 300
Note that keepalives are not always helpful. They help if you have a
firewall which drops your connection after an idle period; but if
-the network between you and the server suffers from breaks in
-connectivity then keepalives can actually make things worse. If a
+the network between you and the server suffers from \i{breaks in
+connectivity} then keepalives can actually make things worse. If a
session is idle, and connectivity is temporarily lost between the
endpoints, but the connectivity is restored before either side tries
to send anything, then there will be no problem - neither endpoint
side doesn't believe there is an open connection any more.
Keepalives can make this sort of problem worse, because they
increase the probability that PuTTY will attempt to send data during
-a break in connectivity. Therefore, you might find they help
+a break in connectivity. (Other types of periodic network activity
+can cause this behaviour; in particular, SSH-2 re-keys can have
+this effect. See \k{config-ssh-kex-rekey}.)
+
+Therefore, you might find that keepalives help
connection loss, or you might find they make it worse, depending on
what \e{kind} of network problems you have between you and the
server.
protocols offer no way of implementing them. (For an alternative, see
\k{config-tcp-keepalives}.)
-Note that if you are using SSH1 and the server has a bug that makes
-it unable to deal with SSH1 ignore messages (see
+Note that if you are using \i{SSH-1} and the server has a bug that makes
+it unable to deal with SSH-1 ignore messages (see
\k{config-ssh-bug-ignore1}), enabling keepalives will have no effect.
-\S{config-nodelay} \q{Disable Nagle's algorithm}
+\S{config-nodelay} \q{Disable \i{Nagle's algorithm}}
\cfg{winhelp-topic}{connection.nodelay}
Nagle's algorithm is a detail of TCP/IP implementations that tries
to minimise the number of small data packets sent down a network
-connection. With Nagle's algorithm enabled, PuTTY's bandwidth usage
+connection. With Nagle's algorithm enabled, PuTTY's \i{bandwidth} usage
will be slightly more efficient; with it disabled, you may find you
get a faster response to your keystrokes when connecting to some
types of server.
-The Nagle algorithm is disabled by default.
+The Nagle algorithm is disabled by default for \i{interactive connections}.
-\S{config-tcp-keepalives} \q{Enable TCP keepalives}
+\S{config-tcp-keepalives} \q{Enable \i{TCP keepalives}}
\cfg{winhelp-topic}{connection.tcpkeepalive}
be configured within PuTTY.
\b If the operating system does not receive a response to a keepalive,
-it may send out more in quick succession and if terminate the connection
+it may send out more in quick succession and terminate the connection
if no response is received.
-TCP keepalives may be more useful for ensuring that half-open connections
+TCP keepalives may be more useful for ensuring that \i{half-open connections}
are terminated than for keeping a connection alive.
TCP keepalives are disabled by default.
-\S{config-address-family} \q{Internet protocol}
+\S{config-address-family} \I{Internet protocol version}\q{Internet protocol}
\cfg{winhelp-topic}{connection.ipversion}
This option allows the user to select between the old and new
-Internet protocols and addressing schemes (IPv4 and IPv6). The
-default setting is \q{Auto}, which means PuTTY will do something
+Internet protocols and addressing schemes (\i{IPv4} and \i{IPv6}).
+The selected protocol will be used for most outgoing network
+connections (including connections to \I{proxy}proxies); however,
+tunnels have their own configuration, for which see
+\k{config-ssh-portfwd-address-family}.
+
+The default setting is \q{Auto}, which means PuTTY will do something
sensible and try to guess which protocol you wanted. (If you specify
-a literal Internet address, it will use whichever protocol that
-address implies. If you provide a hostname, it will see what kinds
+a literal \i{Internet address}, it will use whichever protocol that
+address implies. If you provide a \i{hostname}, it will see what kinds
of address exist for that hostname; it will use IPv6 if there is an
IPv6 address available, and fall back to IPv4 if not.)
If you need to force PuTTY to use a particular protocol, you can
explicitly set this to \q{IPv4} or \q{IPv6}.
+\S{config-loghost} \I{logical host name}\q{Logical name of remote host}
+
+\cfg{winhelp-topic}{connection.loghost}
+
+This allows you to tell PuTTY that the host it will really end up
+connecting to is different from where it thinks it is making a
+network connection.
+
+You might use this, for instance, if you had set up an SSH port
+forwarding in one PuTTY session so that connections to some
+arbitrary port (say, \cw{localhost} port 10022) were forwarded to a
+second machine's SSH port (say, \cw{foovax} port 22), and then
+started a second PuTTY connecting to the forwarded port.
+
+In normal usage, the second PuTTY will access the host key cache
+under the host name and port it actually connected to (i.e.
+\cw{localhost} port 10022 in this example). Using the logical host
+name option, however, you can configure the second PuTTY to cache
+the host key under the name of the host \e{you} know that it's
+\e{really} going to end up talking to (here \c{foovax}).
+
+This can be useful if you expect to connect to the same actual
+server through many different channels (perhaps because your port
+forwarding arrangements keep changing): by consistently setting the
+logical host name, you can arrange that PuTTY will not keep asking
+you to reconfirm its host key. Conversely, if you expect to use the
+same local port number for port forwardings to lots of different
+servers, you probably didn't want any particular server's host key
+cached under that local port number.
+
+If you just enter a host name for this option, PuTTY will cache the
+SSH host key under the default SSH port for that host, irrespective
+of the port you really connected to (since the typical scenario is
+like the above example: you connect to a silly real port number and
+your connection ends up forwarded to the normal port-22 SSH server
+of some other machine). To override this, you can append a port
+number to the logical host name, separated by a colon. E.g. entering
+\cq{foovax:2200} as the logical host name will cause the host key to
+be cached as if you had connected to port 2200 of \c{foovax}.
+
+If you provide a host name using this option, it is also displayed
+in other locations which contain the remote host name, such as the
+default window title and the default SSH password prompt. This
+reflects the fact that this is the host you're \e{really} connecting
+to, which is more important than the mere means you happen to be
+using to contact that host. (This applies even if you're using a
+protocol other than SSH.)
+
\H{config-data} The Data panel
The Data panel allows you to configure various pieces of data which
can be sent to the server to affect your connection at the far end.
-Each options on this panel applies to more than one protocol.
+Each option on this panel applies to more than one protocol.
Options which apply to only one protocol appear on that protocol's
configuration panels.
-\S{config-username} \q{Auto-login username}
+\S{config-username} \q{\ii{Auto-login username}}
\cfg{winhelp-topic}{connection.username}
In this box you can type that user name.
-\S{config-termtype} \q{Terminal-type string}
+\S{config-username-from-env} Use of system username
+
+\cfg{winhelp-topic}{connection.usernamefromenv}
+
+When the previous box (\k{config-username}) is left blank, by default,
+PuTTY will prompt for a username at the time you make a connection.
+
+In some environments, such as the networks of large organisations
+implementing \i{single sign-on}, a more sensible default may be to use
+the name of the user logged in to the local operating system (if any);
+this is particularly likely to be useful with \i{GSSAPI} authentication
+(see \k{config-ssh-auth-gssapi}). This control allows you to change
+the default behaviour.
+
+The current system username is displayed in the dialog as a
+convenience. It is not saved in the configuration; if a saved session
+is later used by a different user, that user's name will be used.
+
+\S{config-termtype} \q{\ii{Terminal-type} string}
\cfg{winhelp-topic}{connection.termtype}
Most servers you might connect to with PuTTY are designed to be
connected to from lots of different types of terminal. In order to
-send the right control sequences to each one, the server will need
+send the right \i{control sequence}s to each one, the server will need
to know what type of terminal it is dealing with. Therefore, each of
the SSH, Telnet and Rlogin protocols allow a text string to be sent
-down the connection describing the terminal.
+down the connection describing the terminal. On a \i{Unix} server,
+this selects an entry from the \i\c{termcap} or \i\c{terminfo} database
+that tells applications what \i{control sequences} to send to the
+terminal, and what character sequences to expect the \i{keyboard}
+to generate.
-PuTTY attempts to emulate the Unix \c{xterm} program, and by default
+PuTTY attempts to emulate the Unix \i\c{xterm} program, and by default
it reflects this by sending \c{xterm} as a terminal-type string. If
you find this is not doing what you want - perhaps the remote
system reports \q{Unknown terminal type} - you could try setting
-this to something different, such as \c{vt220}.
+this to something different, such as \i\c{vt220}.
If you're not sure whether a problem is due to the terminal type
setting or not, you probably need to consult the manual for your
application or your server.
-\S{config-termspeed} \q{Terminal speeds}
+\S{config-termspeed} \q{\ii{Terminal speed}s}
\cfg{winhelp-topic}{connection.termspeed}
which is always \q{as fast as possible}; it is just a hint that is
sometimes used by server software to modify its behaviour. For
instance, if a slow speed is indicated, the server may switch to a
-less bandwidth-hungry display mode.
+less \i{bandwidth}-hungry display mode.
The value is usually meaningless in a network environment, but
PuTTY lets you configure it, in case you find the server is reacting
This option has no effect on Raw connections.
-\S{config-environ} Setting environment variables on the server
+\S{config-environ} Setting \i{environment variables} on the server
\cfg{winhelp-topic}{telnet.environ}
whole mechanism.
Version 2 of the SSH protocol also provides a similar mechanism,
-which is easier to implement without security flaws. Newer SSH2
+which is easier to implement without security flaws. Newer \i{SSH-2}
servers are more likely to support it than older ones.
-This configuration data is not used in the SSHv1, rlogin or raw
+This configuration data is not used in the SSH-1, rlogin or raw
protocols.
To add an environment variable to the list transmitted down the
\cfg{winhelp-topic}{proxy.main}
-The Proxy panel allows you to configure PuTTY to use various types
+The \ii{Proxy} panel allows you to configure PuTTY to use various types
of proxy in order to make its network connections. The settings in
this panel affect the primary network connection forming your PuTTY
-session, but also any extra connections made as a result of SSH port
-forwarding (see \k{using-port-forwarding}).
+session, and also any extra connections made as a result of SSH \i{port
+forwarding} (see \k{using-port-forwarding}).
+
+Note that unlike some software (such as web browsers), PuTTY does not
+attempt to automatically determine whether to use a proxy and (if so)
+which one to use for a given destination. If you need to use a proxy,
+it must always be explicitly configured.
\S{config-proxy-type} Setting the proxy type
setting is \q{None}; in this mode no proxy is used for any
connection.
-\b Selecting \q{HTTP} allows you to proxy your connections through a
-web server supporting the HTTP \cw{CONNECT} command, as documented
+\b Selecting \I{HTTP proxy}\q{HTTP} allows you to proxy your connections
+through a web server supporting the HTTP \cw{CONNECT} command, as documented
in \W{http://www.ietf.org/rfc/rfc2817.txt}{RFC 2817}.
\b Selecting \q{SOCKS 4} or \q{SOCKS 5} allows you to proxy your
-connections through a SOCKS server.
+connections through a \i{SOCKS server}.
\b Many firewalls implement a less formal type of proxy in which a
user can make a Telnet connection directly to the firewall machine
and enter a command such as \c{connect myhost.com 22} to connect
-through to an external host. Selecting \q{Telnet} allows you to tell
-PuTTY to use this type of proxy.
+through to an external host. Selecting \I{Telnet proxy}\q{Telnet}
+allows you to tell PuTTY to use this type of proxy.
+
+\b Selecting \I{Local proxy}\q{Local} allows you to specify an arbitrary
+command on the local machine to act as a proxy. When the session is
+started, instead of creating a TCP connection, PuTTY runs the command
+(specified in \k{config-proxy-command}), and uses its standard input and
+output streams.
+
+\lcont{
+This could be used, for instance, to talk to some kind of network proxy
+that PuTTY does not natively support; or you could tunnel a connection
+over something other than TCP/IP entirely.
+
+If you want your local proxy command to make a secondary SSH
+connection to a proxy host and then tunnel the primary connection
+over that, you might well want the \c{-nc} command-line option in
+Plink. See \k{using-cmdline-ncmode} for more information.
+}
\S{config-proxy-exclude} Excluding parts of the network from proxying
This excludes both of the above ranges at once.
-Connections to the local host (the host name \c{localhost}, and any
-loopback IP address) are never proxied, even if the proxy exclude
+Connections to the local host (the host name \i\c{localhost}, and any
+\i{loopback IP address}) are never proxied, even if the proxy exclude
list does not explicitly contain them. It is very unlikely that this
behaviour would ever cause problems, but if it does you can change
it by enabling \q{Consider proxying local host connections}.
-Note that if you are doing DNS at the proxy (see
+Note that if you are doing \I{proxy DNS}DNS at the proxy (see
\k{config-proxy-dns}), you should make sure that your proxy
exclusion settings do not depend on knowing the IP address of a
host. If the name is passed on to the proxy without PuTTY looking it
up, it will never know the IP address and cannot check it against
your list.
-\S{config-proxy-dns} Name resolution when using a proxy
+\S{config-proxy-dns} \I{proxy DNS}\ii{Name resolution} when using a proxy
\cfg{winhelp-topic}{proxy.dns}
If you are using a proxy to access a private network, it can make a
-difference whether DNS name resolution is performed by PuTTY itself
+difference whether \i{DNS} name resolution is performed by PuTTY itself
(on the client machine) or performed by the proxy.
The \q{Do DNS name lookup at proxy end} configuration option allows
proxy without trying to look them up first.
If you set this option to \q{Auto} (the default), PuTTY will do
-something it considers appropriate for each type of proxy. Telnet
-and HTTP proxies will have host names passed straight to them; SOCKS
-proxies will not.
+something it considers appropriate for each type of proxy. Telnet,
+HTTP, and SOCKS5 proxies will have host names passed straight to
+them; SOCKS4 proxies will not.
Note that if you are doing DNS at the proxy, you should make sure
that your proxy exclusion settings (see \k{config-proxy-exclude}) do
all SOCKS 4 servers provide this extension. If you enable proxy DNS
and your SOCKS 4 server cannot deal with it, this might be why.
-\S{config-proxy-auth} Username and password
+\S{config-proxy-auth} \I{proxy username}Username and \I{proxy password}password
\cfg{winhelp-topic}{proxy.auth}
-If your proxy requires authentication, you can enter a username and
-a password in the \q{Username} and \q{Password} boxes.
+If your proxy requires \I{proxy authentication}authentication, you can
+enter a username and a password in the \q{Username} and \q{Password} boxes.
-Note that if you save your session, the proxy password will be
-saved in plain text, so anyone who can access your PuTTY
+\I{security hazard}Note that if you save your session, the proxy
+password will be saved in plain text, so anyone who can access your PuTTY
configuration data will be able to discover it.
Authentication is not fully supported for all forms of proxy:
\b With SOCKS 5, authentication is via \i{CHAP} if the proxy
supports it (this is not supported in \i{PuTTYtel}); otherwise the
-password is sent to the proxy in plain text.
+password is sent to the proxy in \I{plaintext password}plain text.
\b With HTTP proxying, the only currently supported authentication
-method is \q{basic}, where the password is sent to the proxy in plain
-text.
+method is \I{HTTP basic}\q{basic}, where the password is sent to the proxy
+in \I{plaintext password}plain text.
}
passwords.
\b You can specify a way to include a username and password in the
-Telnet proxy command (see \k{config-proxy-command}).
+Telnet/Local proxy command (see \k{config-proxy-command}).
-\S{config-proxy-command} Specifying the Telnet proxy command
+\S{config-proxy-command} Specifying the Telnet or Local proxy command
\cfg{winhelp-topic}{proxy.command}
-If you are using the Telnet proxy type, the usual command required
+If you are using the \i{Telnet proxy} type, the usual command required
by the firewall's Telnet server is \c{connect}, followed by a host
name and a port number. If your proxy needs a different command,
you can enter an alternative here.
+If you are using the \i{Local proxy} type, the local command to run
+is specified here.
+
In this string, you can use \c{\\n} to represent a new-line, \c{\\r}
to represent a carriage return, \c{\\t} to represent a tab
character, and \c{\\x} followed by two hex digits to represent any
Also, the special strings \c{%host} and \c{%port} will be replaced
by the host name and port number you want to connect to. The strings
\c{%user} and \c{%pass} will be replaced by the proxy username and
-password you specify. To get a literal \c{%} sign, enter \c{%%}.
+password you specify. The strings \c{%proxyhost} and \c{%proxyport}
+will be replaced by the host details specified on the \e{Proxy} panel,
+if any (this is most likely to be useful for the Local proxy type).
+To get a literal \c{%} sign, enter \c{%%}.
-If the Telnet proxy server prompts for a username and password
+If a Telnet proxy server prompts for a username and password
before commands can be sent, you can use a command such as:
\c %user\n%pass\nconnect %host %port\n
tokens in the Telnet command, then the \q{Username} and \q{Password}
configuration fields will be ignored.
-\H{config-telnet} The Telnet panel
+\H{config-telnet} The \i{Telnet} panel
The Telnet panel allows you to configure options that only apply to
Telnet sessions.
\cfg{winhelp-topic}{telnet.oldenviron}
-The original Telnet mechanism for passing environment variables was
+The original Telnet mechanism for passing \i{environment variables} was
badly specified. At the time the standard (RFC 1408) was written,
BSD telnet implementations were already supporting the feature, and
the intention of the standard was to describe the behaviour the BSD
Sadly there was a typing error in the standard when it was issued,
and two vital function codes were specified the wrong way round. BSD
implementations did not change, and the standard was not corrected.
-Therefore, it's possible you might find either BSD or RFC-compliant
+Therefore, it's possible you might find either \i{BSD} or \i{RFC}-compliant
implementations out there. This switch allows you to choose which
one PuTTY claims to be.
The problem was solved by issuing a second standard, defining a new
-Telnet mechanism called \cw{NEW_ENVIRON}, which behaved exactly like
-the original \cw{OLD_ENVIRON} but was not encumbered by existing
+Telnet mechanism called \i\cw{NEW_ENVIRON}, which behaved exactly like
+the original \i\cw{OLD_ENVIRON} but was not encumbered by existing
implementations. Most Telnet servers now support this, and it's
unambiguous. This feature should only be needed if you have trouble
passing environment variables to quite an old server.
-\S{config-ptelnet} Passive and active Telnet negotiation modes
+\S{config-ptelnet} Passive and active \i{Telnet negotiation} modes
\cfg{winhelp-topic}{telnet.passive}
PuTTY can use two different strategies for negotiation:
-\b In \e{active} mode, PuTTY starts to send negotiations as soon as
-the connection is opened.
+\b In \I{active Telnet negotiation}\e{active} mode, PuTTY starts to send
+negotiations as soon as the connection is opened.
-\b In \e{passive} mode, PuTTY will wait to negotiate until it sees a
-negotiation from the server.
+\b In \I{passive Telnet negotiation}\e{passive} mode, PuTTY will wait to
+negotiate until it sees a negotiation from the server.
The obvious disadvantage of passive mode is that if the server is
also operating in a passive mode, then negotiation will never begin
at all. For this reason PuTTY defaults to active mode.
However, sometimes passive mode is required in order to successfully
-get through certain types of firewall and Telnet proxy server. If
-you have confusing trouble with a firewall, you could try enabling
+get through certain types of firewall and \i{Telnet proxy} server. If
+you have confusing trouble with a \i{firewall}, you could try enabling
passive mode to see if it helps.
-\S{config-telnetkey} \q{Keyboard sends Telnet special commands}
+\S{config-telnetkey} \q{Keyboard sends \i{Telnet special commands}}
\cfg{winhelp-topic}{telnet.specialkeys}
You probably shouldn't enable this
unless you know what you're doing.
-\S{config-telnetnl} \q{Return key sends Telnet New Line instead of ^M}
+\S{config-telnetnl} \q{Return key sends \i{Telnet New Line} instead of ^M}
\cfg{winhelp-topic}{telnet.newline}
Unlike most other remote login protocols, the Telnet protocol has a
-special \q{new line} code that is not the same as the usual line
+special \q{\i{new line}} code that is not the same as the usual line
endings of Control-M or Control-J. By default, PuTTY sends the
Telnet New Line code when you press Return, instead of sending
Control-M as it does in most other protocols.
\H{config-rlogin} The Rlogin panel
-The Rlogin panel allows you to configure options that only apply to
+The \i{Rlogin} panel allows you to configure options that only apply to
Rlogin sessions.
-\S{config-rlogin-localuser} \q{Local username}
+\S{config-rlogin-localuser} \I{local username in Rlogin}\q{Local username}
\cfg{winhelp-topic}{rlogin.localuser}
Rlogin allows an automated (password-free) form of login by means of
-a file called \c{.rhosts} on the server. You put a line in your
+a file called \i\c{.rhosts} on the server. You put a line in your
\c{.rhosts} file saying something like \c{jbloggs@pc1.example.com},
and then when you make an Rlogin connection the client transmits the
username of the user running the Rlogin client. The server checks
the username and hostname against \c{.rhosts}, and if they match it
-does not ask for a password.
+\I{passwordless login}does not ask for a password.
This only works because Unix systems contain a safeguard to stop a
user from pretending to be another user in an Rlogin connection.
-Rlogin connections have to come from port numbers below 1024, and
-Unix systems prohibit this to unprivileged processes; so when the
+Rlogin connections have to come from \I{privileged port}port numbers below
+1024, and Unix systems prohibit this to unprivileged processes; so when the
server sees a connection from a low-numbered port, it assumes the
client end of the connection is held by a privileged (and therefore
trusted) process, so it believes the claim of who the user is.
\c{.rhosts} mechanism is completely useless for securely
distinguishing several different users on a Windows machine. If you
have a \c{.rhosts} entry pointing at a Windows PC, you should assume
-that \e{anyone} using that PC can spoof your username in an Rlogin
-connection and access your account on the server.
+that \e{anyone} using that PC can \i{spoof} your username in
+an Rlogin connection and access your account on the server.
The \q{Local username} control allows you to specify what user name
-PuTTY should claim you have, in case it doesn't match your Windows
-user name (or in case you didn't bother to set up a Windows user
+PuTTY should claim you have, in case it doesn't match your \i{Windows
+user name} (or in case you didn't bother to set up a Windows user
name).
\H{config-ssh} The SSH panel
-The SSH panel allows you to configure options that only apply to
+The \i{SSH} panel allows you to configure options that only apply to
SSH sessions.
\S{config-command} Executing a specific command on the server
In SSH, you don't have to run a general shell session on the server.
Instead, you can choose to run a single specific command (such as a
mail user agent, for example). If you want to do this, enter the
-command in the \q{Remote command} box.
-
-\S{config-ssh-pty} \q{Don't allocate a pseudo-terminal}
-
-\cfg{winhelp-topic}{ssh.nopty}
+command in the \q{\ii{Remote command}} box.
-When connecting to a Unix system, most interactive shell sessions
-are run in a \e{pseudo-terminal}, which allows the Unix system to
-pretend it's talking to a real physical terminal device but allows
-the SSH server to catch all the data coming from that fake device
-and send it back to the client.
+Note that most servers will close the session after executing the
+command.
-Occasionally you might find you have a need to run a session \e{not}
-in a pseudo-terminal. In PuTTY, this is generally only useful for
-very specialist purposes; although in Plink (see \k{plink}) it is
-the usual way of working.
-
-\S{config-ssh-noshell} \q{Don't start a shell or command at all}
+\S{config-ssh-noshell} \q{Don't start a \I{remote shell}shell or
+\I{remote command}command at all}
\cfg{winhelp-topic}{ssh.noshell}
If you tick this box, PuTTY will not attempt to run a shell or
command after connecting to the remote server. You might want to use
-this option if you are only using the SSH connection for port
-forwarding, and your user account on the server does not have the
+this option if you are only using the SSH connection for \i{port
+forwarding}, and your user account on the server does not have the
ability to run a shell.
-This feature is only available in SSH protocol version 2 (since the
+This feature is only available in \i{SSH protocol version 2} (since the
version 1 protocol assumes you will always want to run a shell).
This feature can also be enabled using the \c{-N} command-line
will be by pressing Control-C or sending a kill signal from another
program.
-\S{config-ssh-comp} \q{Enable compression}
+\S{config-ssh-comp} \q{Enable \i{compression}}
\cfg{winhelp-topic}{ssh.compress}
the server is compressed before sending, and decompressed at the
client end. Likewise, data sent by PuTTY to the server is compressed
first and the server decompresses it at the other end. This can help
-make the most of a low-bandwidth connection.
+make the most of a low-\i{bandwidth} connection.
-\S{config-ssh-prot} \q{Preferred SSH protocol version}
+\S{config-ssh-prot} \q{Preferred \i{SSH protocol version}}
\cfg{winhelp-topic}{ssh.protocol}
-This allows you to select whether you would like to use SSH protocol
-version 1 or version 2. \#{FIXME: say something about this elsewhere?}
+This allows you to select whether you would like to use \i{SSH protocol
+version 1} or \I{SSH-2}version 2. \#{FIXME: say something about this elsewhere?}
PuTTY will attempt to use protocol 1 if the server you connect to
does not offer protocol 2, and vice versa.
if the server you connect to offers the SSH protocol version you
have specified.
-\S{config-ssh-encryption} Encryption algorithm selection
+\S{config-ssh-encryption} \ii{Encryption} algorithm selection
\cfg{winhelp-topic}{ssh.ciphers}
-PuTTY supports a variety of different encryption algorithms, and
+PuTTY supports a variety of different \i{encryption algorithm}s, and
allows you to choose which one you prefer to use. You can do this by
dragging the algorithms up and down in the list box (or moving them
using the Up and Down buttons) to specify a preference order. When
PuTTY currently supports the following algorithms:
-\b AES (Rijndael) - 256, 192, or 128-bit CBC (SSH-2 only)
+\b \i{AES} (Rijndael) - 256, 192, or 128-bit SDCTR or CBC (SSH-2 only)
+
+\b \i{Arcfour} (RC4) - 256 or 128-bit stream cipher (SSH-2 only)
-\b Blowfish - 128-bit CBC
+\b \i{Blowfish} - 256-bit SDCTR (SSH-2 only) or 128-bit CBC
-\b Triple-DES - 168-bit CBC
+\b \ii{Triple-DES} - 168-bit SDCTR (SSH-2 only) or CBC
-\b Single-DES - 56-bit CBC (see below for SSH-2)
+\b \ii{Single-DES} - 56-bit CBC (see below for SSH-2)
If the algorithm PuTTY finds is below the \q{warn below here} line,
you will see a warning box when you make the connection:
get two warnings similar to the one above, possibly with different
encryptions.
-Single-DES is not recommended in the SSH 2 draft protocol
+Single-DES is not recommended in the SSH-2 protocol
standards, but one or two server implementations do support it.
PuTTY can use single-DES to interoperate with
these servers if you enable the \q{Enable legacy use of single-DES in
-SSH 2} option; by default this is disabled and PuTTY will stick to
+SSH-2} option; by default this is disabled and PuTTY will stick to
recommended ciphers.
\H{config-ssh-kex} The Kex panel
\# FIXME: This whole section is draft. Feel free to revise.
-The Kex panel (short for \q{key exchange}) allows you to configure
+The Kex panel (short for \q{\i{key exchange}}) allows you to configure
options related to SSH-2 key exchange.
Key exchange occurs at the start of an SSH connection (and
-occasionally thereafter); it establishes a shared secret that is used
+occasionally thereafter); it establishes a \i{shared secret} that is used
as the basis for all of SSH's security features. It is therefore very
important for the security of the connection that the key exchange is
secure.
This entire panel is only relevant to SSH protocol version 2; none of
these settings affect SSH-1 at all.
-\S{config-ssh-kex-order} Key exchange algorithm selection
+\S{config-ssh-kex-order} \ii{Key exchange algorithm} selection
\cfg{winhelp-topic}{ssh.kex.order}
to choose which one you prefer to use; configuration is similar to
cipher selection (see \k{config-ssh-encryption}).
-PuTTY currently supports the following varieties of Diffie-Hellman key
-exchange:
+PuTTY currently supports the following varieties of \i{Diffie-Hellman key
+exchange}:
\b \q{Group 14}: a well-known 2048-bit group.
client or server machines, and may be the only method supported by
older server software.
-\b \q{Group exchange}: with this method, instead of using a fixed
+\b \q{\ii{Group exchange}}: with this method, instead of using a fixed
group, PuTTY requests that the server suggest a group to use for key
exchange; the server can avoid groups known to be weak, and possibly
invent new ones over time, without any changes required to PuTTY's
configuration. We recommend use of this method, if possible.
+In addition, PuTTY supports \i{RSA key exchange}, which requires much less
+computational effort on the part of the client, and somewhat less on
+the part of the server, than Diffie-Hellman key exchange.
+
If the first algorithm PuTTY finds is below the \q{warn below here}
line, you will see a warning box when you make the connection, similar
to that for cipher selection (see \k{config-ssh-encryption}).
-\S{config-ssh-kex-rekey} Repeat key exchange
+\S{config-ssh-kex-rekey} \ii{Repeat key exchange}
\cfg{winhelp-topic}{ssh.kex.repeat}
exchange (\q{rekey}). You can also force a key exchange at any time
from the Special Commands menu (see \k{using-specials}).
-\# FIXME: do we have any additions to the SSH-2 drafts' advice on
+\# FIXME: do we have any additions to the SSH-2 specs' advice on
these values? Do we want to enforce any limits?
\b \q{Max minutes before rekey} specifies the amount of time that is
specification recommends a timeout of at most 60 minutes.
You might have a need to disable time-based rekeys completely for the same
-reasons that keepalives aren't always helpful. If you anticipate
+reasons that \i{keepalives} aren't always helpful. If you anticipate
suffering a network dropout of several hours in the middle of an SSH
connection, but were not actually planning to send \e{data} down
that connection during those hours, then an attempted rekey in the
middle of the dropout will probably cause the connection to be
abandoned, whereas if rekeys are disabled then the connection should
-in principle survive (in the absence of interfering firewalls). See
+in principle survive (in the absence of interfering \i{firewalls}). See
\k{config-keepalive} for more discussion of these issues; for these
purposes, rekeys have much the same properties as keepalives.
(Except that rekeys have cryptographic value in themselves, so you
}
-Disabling data-based rekeys entirely is a bad idea. The integrity,
-and to a lesser extent, confidentiality of the SSH-2 protocol depend
+Disabling data-based rekeys entirely is a bad idea. The \i{integrity},
+and to a lesser extent, \i{confidentiality} of the SSH-2 protocol depend
in part on rekeys occuring before a 32-bit packet sequence number
wraps around. Unlike time-based rekeys, data-based rekeys won't occur
when the SSH connection is idle, so they shouldn't cause the same
\H{config-ssh-auth} The Auth panel
-The Auth panel allows you to configure authentication options for
+The Auth panel allows you to configure \i{authentication} options for
SSH sessions.
-\S{config-ssh-tis} \q{Attempt TIS or CryptoCard authentication}
+\S{config-ssh-noauth} \q{Bypass authentication entirely}
+
+\cfg{winhelp-topic}{ssh.auth.bypass}
+
+In SSH-2, it is possible to establish a connection without using SSH's
+mechanisms to identify or authenticate oneself to the server. Some
+servers may prefer to handle authentication in the data channel, for
+instance, or may simply require no authentication whatsoever.
+
+By default, PuTTY assumes the server requires authentication (most
+do), and thus must provide a username. If you find you are getting
+unwanted username prompts, you could try checking this option.
+
+This option only affects SSH-2 connections. SSH-1 connections always
+require an authentication step.
+
+\S{config-ssh-banner} \q{Display pre-authentication banner}
+
+\cfg{winhelp-topic}{ssh.auth.banner}
+
+SSH-2 servers can provide a message for clients to display to the
+prospective user before the user logs in; this is sometimes known as a
+pre-authentication \q{\i{banner}}. Typically this is used to provide
+information about the server and legal notices.
+
+By default, PuTTY displays this message before prompting for a
+password or similar credentials (although, unfortunately, not before
+prompting for a login name, due to the nature of the protocol design).
+By unchecking this option, display of the banner can be suppressed
+entirely.
+
+\S{config-ssh-tryagent} \q{Attempt authentication using Pageant}
+
+\cfg{winhelp-topic}{ssh.auth.pageant}
+
+If this option is enabled, then PuTTY will look for Pageant (the SSH
+private-key storage agent) and attempt to authenticate with any
+suitable public keys Pageant currently holds.
+
+This behaviour is almost always desirable, and is therefore enabled
+by default. In rare cases you might need to turn it off in order to
+force authentication by some non-public-key method such as
+passwords.
+
+This option can also be controlled using the \c{-noagent}
+command-line option. See \k{using-cmdline-agentauth}.
+
+See \k{pageant} for more information about Pageant in general.
+
+\S{config-ssh-tis} \q{Attempt \I{TIS authentication}TIS or
+\i{CryptoCard authentication}}
\cfg{winhelp-topic}{ssh.auth.tis}
-TIS and CryptoCard authentication are simple challenge/response
-forms of authentication available in SSH protocol version 1 only.
-You might use them if you were using S/Key one-time passwords, for
-example, or if you had a physical security token that generated
-responses to authentication challenges.
+TIS and CryptoCard authentication are (despite their names) generic
+forms of simple \I{challenge/response authentication}challenge/response
+authentication available in SSH protocol version 1 only. You might use
+them if you were using \i{S/Key} \i{one-time passwords}, for example,
+or if you had a physical \i{security token} that generated responses
+to authentication challenges. They can even be used to prompt for
+simple passwords.
With this switch enabled, PuTTY will attempt these forms of
authentication if the server is willing to try them. You will be
-presented with a challenge string (which will be different every
+presented with a challenge string (which may be different every
time) and must supply the correct response in order to log in. If
your server supports this, you should talk to your system
administrator about precisely what form these challenges and
responses take.
-\S{config-ssh-ki} \q{Attempt keyboard-interactive authentication}
+\S{config-ssh-ki} \q{Attempt \i{keyboard-interactive authentication}}
\cfg{winhelp-topic}{ssh.auth.ki}
-The SSH 2 equivalent of TIS authentication is called
+The SSH-2 equivalent of TIS authentication is called
\q{keyboard-interactive}. It is a flexible authentication method
using an arbitrary sequence of requests and responses; so it is not
-only useful for challenge/response mechanisms such as S/Key, but it
-can also be used for (for example) asking the user for a new
-password when the old one has expired.
+only useful for \I{challenge/response authentication}challenge/response
+mechanisms such as \i{S/Key}, but it can also be used for (for example)
+asking the user for a \I{password expiry}new password when the old one
+has expired.
PuTTY leaves this option enabled by default, but supplies a switch
to turn it off in case you should have trouble with it.
-\S{config-ssh-agentfwd} \q{Allow agent forwarding}
+\S{config-ssh-agentfwd} \q{Allow \i{agent forwarding}}
\cfg{winhelp-topic}{ssh.auth.agentfwd}
This option allows the SSH server to open forwarded connections back
-to your local copy of Pageant. If you are not running Pageant, this
+to your local copy of \i{Pageant}. If you are not running Pageant, this
option will do nothing.
See \k{pageant} for general information on Pageant, and
there is a security risk involved with enabling this option; see
\k{pageant-security} for details.
-\S{config-ssh-changeuser} \q{Allow attempted changes of username in SSH2}
+\S{config-ssh-changeuser} \q{Allow attempted \i{changes of username} in SSH-2}
\cfg{winhelp-topic}{ssh.auth.changeuser}
-In the SSH 1 protocol, it is impossible to change username after
+In the SSH-1 protocol, it is impossible to change username after
failing to authenticate. So if you mis-type your username at the
PuTTY \q{login as:} prompt, you will not be able to change it except
by restarting PuTTY.
-The SSH 2 protocol \e{does} allow changes of username, in principle,
-but does not make it mandatory for SSH 2 servers to accept them. In
-particular, OpenSSH does not accept a change of username; once you
+The SSH-2 protocol \e{does} allow changes of username, in principle,
+but does not make it mandatory for SSH-2 servers to accept them. In
+particular, \i{OpenSSH} does not accept a change of username; once you
have sent one username, it will reject attempts to try to
authenticate as another user. (Depending on the version of OpenSSH,
it may quietly return failure for all login attempts, or it may send
your server can cope with it, you can enable the \q{Allow attempted
changes of username} option to modify PuTTY's behaviour.
-\S{config-ssh-privkey} \q{Private key file for authentication}
+\S{config-ssh-privkey} \q{\ii{Private key} file for authentication}
\cfg{winhelp-topic}{ssh.auth.privkey}
This box is where you enter the name of your private key file if you
-are using public key authentication. See \k{pubkey} for information
+are using \i{public key authentication}. See \k{pubkey} for information
about public key authentication in SSH.
-This key must be in PuTTY's native format (\c{*.PPK}).
+This key must be in PuTTY's native format (\c{*.\i{PPK}}). If you have a
+private key in another format that you want to use with PuTTY, see
+\k{puttygen-conversions}.
+
+If a key file is specified here, and \i{Pageant} is running (see
+\k{pageant}), PuTTY will first try asking Pageant to authenticate with
+that key, and ignore any other keys Pageant may have. If that fails,
+PuTTY will ask for a passphrase as normal.
+
+\H{config-ssh-auth-gssapi} The \i{GSSAPI} panel
+
+\cfg{winhelp-topic}{ssh.auth.gssapi}
+
+The \q{GSSAPI} subpanel of the \q{Auth} panel controls the use of
+GSSAPI authentication. This is a mechanism which delegates the
+authentication exchange to a library elsewhere on the client
+machine, which in principle can authenticate in many different ways
+but in practice is usually used with the \i{Kerberos} \i{single sign-on}
+protocol.
+
+GSSAPI is only available in the SSH-2 protocol.
+
+The topmost control on the GSSAPI subpanel is the checkbox labelled
+\q{Attempt GSSAPI authentication}. If this is disabled, GSSAPI will
+not be attempted at all and the rest of this panel is unused. If it
+is enabled, GSSAPI authentication will be attempted, and (typically)
+if your client machine has valid Kerberos credentials loaded, then
+PuTTY should be able to authenticate automatically to servers that
+support Kerberos logins.
+
+\S{config-ssh-auth-gssapi-delegation} \q{Allow GSSAPI credential
+delegation}
+
+\cfg{winhelp-topic}{ssh.auth.gssapi.delegation}
+
+\i{GSSAPI credential delegation} is a mechanism for passing on your
+Kerberos (or other) identity to the session on the SSH server. If
+you enable this option, then not only will PuTTY be able to log in
+automatically to a server that accepts your Kerberos credentials,
+but also you will be able to connect out from that server to other
+Kerberos-supporting services and use the same credentials just as
+automatically.
+
+(This option is the Kerberos analogue of SSH agent forwarding; see
+\k{pageant-forward} for some information on that.)
+
+Note that, like SSH agent forwarding, there is a security
+implication in the use of this option: the administrator of the
+server you connect to, or anyone else who has cracked the
+administrator account on that server, could fake your identity when
+connecting to further Kerberos-supporting services. However,
+Kerberos sites are typically run by a central authority, so the
+administrator of one server is likely to already have access to the
+other services too; so this would typically be less of a risk than
+SSH agent forwarding.
+
+\S{config-ssh-auth-gssapi-libraries} Preference order for GSSAPI
+libraries
+
+\cfg{winhelp-topic}{ssh.auth.gssapi.libraries}
+
+GSSAPI is a mechanism which allows more than one authentication
+method to be accessed through the same interface. Therefore, more
+than one authentication library may exist on your system which can
+be accessed using GSSAPI.
+
+PuTTY contains native support for a few well-known such libraries,
+and will look for all of them on your system and use whichever it
+finds. If more than one exists on your system and you need to use a
+specific one, you can adjust the order in which it will search using
+this preference list control.
+
+One of the options in the preference list is to use a user-specified
+GSSAPI library. If the library you want to use is not mentioned by
+name in PuTTY's list of options, you can enter its full pathname in
+the \q{User-supplied GSSAPI library path} field, and move the
+\q{User-supplied GSSAPI library} option in the preference list to
+make sure it is selected before anything else.
+
+\H{config-ssh-tty} The TTY panel
+
+The TTY panel lets you configure the remote pseudo-terminal.
+
+\S{config-ssh-pty} \I{pseudo-terminal allocation}\q{Don't allocate
+a pseudo-terminal}
+
+\cfg{winhelp-topic}{ssh.nopty}
+
+When connecting to a \i{Unix} system, most \I{interactive
+connections}interactive shell sessions are run in a \e{pseudo-terminal},
+which allows the Unix system to pretend it's talking to a real physical
+terminal device but allows the SSH server to catch all the data coming
+from that fake device and send it back to the client.
+
+Occasionally you might find you have a need to run a session \e{not}
+in a pseudo-terminal. In PuTTY, this is generally only useful for
+very specialist purposes; although in Plink (see \k{plink}) it is
+the usual way of working.
+
+\S{config-ttymodes} Sending \i{terminal modes}
+
+\cfg{winhelp-topic}{ssh.ttymodes}
+
+The SSH protocol allows the client to send \q{terminal modes} for
+the remote pseudo-terminal. These usually control the server's
+expectation of the local terminal's behaviour.
+
+If your server does not have sensible defaults for these modes, you
+may find that changing them here helps. If you don't understand any of
+this, it's safe to leave these settings alone.
+
+(None of these settings will have any effect if no pseudo-terminal
+is requested or allocated.)
+
+You can add or modify a mode by selecting it from the drop-down list,
+choosing whether it's set automatically or to a specific value with
+the radio buttons and edit box, and hitting \q{Add}. A mode (or
+several) can be removed from the list by selecting them and hitting
+\q{Remove}. The effect of the mode list is as follows:
+
+\b If a mode is not on the list, it will not be specified to the
+server under any circumstances.
+
+\b If a mode is on the list:
+
+\lcont{
+
+\b If the \q{Auto} option is selected, the PuTTY tools will decide
+whether to specify that mode to the server, and if so, will send
+a sensible value.
+
+\lcont{
+
+PuTTY proper will send modes that it has an opinion on (currently only
+the code for the Backspace key, \cw{ERASE}). Plink on Unix
+will propagate appropriate modes from the local terminal, if any.
+
+}
+
+\b If a value is specified, it will be sent to the server under all
+circumstances. The precise syntax of the value box depends on the
+mode.
+
+}
+
+By default, all of the available modes are listed as \q{Auto},
+which should do the right thing in most circumstances.
+
+The precise effect of each setting, if any, is up to the server. Their
+names come from \i{POSIX} and other Unix systems, and they are most
+likely to have a useful effect on such systems. (These are the same
+settings that can usually be changed using the \i\c{stty} command once
+logged in to such servers.)
+
+Some notable modes are described below; for fuller explanations, see
+your server documentation.
+
+\b \I{ERASE special character}\cw{ERASE} is the character that when typed
+by the user will delete one space to the left. When set to \q{Auto}
+(the default setting), this follows the setting of the local Backspace
+key in PuTTY (see \k{config-backspace}).
+
+\lcont{
+This and other \i{special character}s are specified using \c{^C} notation
+for Ctrl-C, and so on. Use \c{^<27>} or \c{^<0x1B>} to specify a
+character numerically, and \c{^~} to get a literal \c{^}. Other
+non-control characters are denoted by themselves. Leaving the box
+entirely blank indicates that \e{no} character should be assigned to
+the specified function, although this may not be supported by all
+servers.
+}
+
+\b \I{QUIT special character}\cw{QUIT} is a special character that
+usually forcefully ends the current process on the server
+(\cw{SIGQUIT}). On many servers its default setting is Ctrl-backslash
+(\c{^\\}), which is easy to accidentally invoke on many keyboards. If
+this is getting in your way, you may want to change it to another
+character or turn it off entirely.
+
+\b Boolean modes such as \cw{ECHO} and \cw{ICANON} can be specified in
+PuTTY in a variety of ways, such as \cw{true}/\cw{false},
+\cw{yes}/\cw{no}, and \cw{0}/\cw{1}.
+
+\b Terminal speeds are configured elsewhere; see \k{config-termspeed}.
\H{config-ssh-x11} The X11 panel
\cfg{winhelp-topic}{ssh.tunnels.x11}
-The X11 panel allows you to configure forwarding of X11 over an
+The X11 panel allows you to configure \i{forwarding of X11} over an
SSH connection.
If your server lets you run X Window System applications, X11
To enable X11 forwarding, check the \q{Enable X11 forwarding} box.
If your X display is somewhere unusual, you will need to enter its
location in the \q{X display location} box; if this is left blank,
-PuTTY try to find a sensible default in the environment, or use the
+PuTTY will try to find a sensible default in the environment, or use the
primary local display (\c{:0}) if that fails.
See \k{using-x-forwarding} for more information about X11
forwarding.
-\S{config-ssh-x11auth} Remote X11 authentication
+\S{config-ssh-x11auth} Remote \i{X11 authentication}
\cfg{winhelp-topic}{ssh.tunnels.x11auth}
data is invented, and checked, by PuTTY.
The usual authorisation method used for this is called
-\cw{MIT-MAGIC-COOKIE-1}. This is a simple password-style protocol:
+\i\cw{MIT-MAGIC-COOKIE-1}. This is a simple password-style protocol:
the X client sends some cookie data to the server, and the server
checks that it matches the real cookie. The cookie data is sent over
an unencrypted X11 connection; so if you allow a client on a third
machine to access the virtual X server, then the cookie will be sent
in the clear.
-PuTTY offers the alternative protocol \cw{XDM-AUTHORIZATION-1}. This
+PuTTY offers the alternative protocol \i\cw{XDM-AUTHORIZATION-1}. This
is a cryptographically authenticated protocol: the data sent by the
X client is different every time, and it depends on the IP address
and port of the client's end of the connection and is also stamped
\cw{XDM-AUTHORIZATION-1}, so they will not know what to do with the
data PuTTY has provided.
-\b This authentication mechanism will only work in SSH v2. In SSH
-v1, the SSH server does not tell the client the source address of
+\b This authentication mechanism will only work in SSH-2. In SSH-1,
+the SSH server does not tell the client the source address of
a forwarded connection in a machine-readable format, so it's
impossible to verify the \cw{XDM-AUTHORIZATION-1} data.
PuTTY's default is \cw{MIT-MAGIC-COOKIE-1}. If you change it, you
should be sure you know what you're doing.
-\H{config-ssh-portfwd} The Tunnels panel
+\S{config-ssh-xauthority} X authority file for local display
+
+\cfg{winhelp-topic}{ssh.tunnels.xauthority}
+
+If you are using X11 forwarding, the local X server to which your
+forwarded connections are eventually directed may itself require
+authorisation.
+
+Some Windows X servers do not require this: they do authorisation by
+simpler means, such as accepting any connection from the local
+machine but not from anywhere else. However, if your X server does
+require authorisation, then PuTTY needs to know what authorisation
+is required.
+
+One way in which this data might be made available is for the X
+server to store it somewhere in a file which has the same format
+as the Unix \c{.Xauthority} file. If this is how your Windows X
+server works, then you can tell PuTTY where to find this file by
+configuring this option. By default, PuTTY will not attempt to find
+any authorisation for your local display.
+
+\H{config-ssh-portfwd} \I{port forwarding}The Tunnels panel
\cfg{winhelp-topic}{ssh.tunnels.portfwd}
The Tunnels panel allows you to configure tunnelling of arbitrary
connection types through an SSH connection.
-Port forwarding allows you to tunnel other types of network
-connection down an SSH session. See \k{using-port-forwarding} for a
+Port forwarding allows you to tunnel other types of \i{network
+connection} down an SSH session. See \k{using-port-forwarding} for a
general discussion of port forwarding and how it works.
The port forwarding section in the Tunnels panel shows a list of all
To add a port forwarding:
\b Set one of the \q{Local} or \q{Remote} radio buttons, depending
-on whether you want to forward a local port to a remote destination
-(\q{Local}) or forward a remote port to a local destination
-(\q{Remote}). Alternatively, select \q{Dynamic} if you want PuTTY to
-provide a local SOCKS 4/4A/5 proxy on a local port.
-
-\b Enter a source port number into the \q{Source port} box. For
+on whether you want to \I{local port forwarding}forward a local port
+to a remote destination (\q{Local}) or \I{remote port forwarding}forward
+a remote port to a local destination (\q{Remote}). Alternatively,
+select \q{Dynamic} if you want PuTTY to \I{dynamic port forwarding}provide
+a local SOCKS 4/4A/5 proxy on a local port (note that this proxy only
+supports TCP connections; the SSH protocol does not support forwarding
+\i{UDP}).
+
+\b Enter a source \i{port number} into the \q{Source port} box. For
local forwardings, PuTTY will listen on this port of your PC. For
remote forwardings, your SSH server will listen on this port of the
remote machine. Note that most servers will not allow you to listen
-on port numbers less than 1024.
+on \I{privileged port}port numbers less than 1024.
\b If you have selected \q{Local} or \q{Remote} (this step is not
needed with \q{Dynamic}), enter a hostname and port number separated
To remove a port forwarding, simply select its details in the list
box, and click the \q{Remove} button.
-In the \q{Source port} box, you can also optionally enter an IP
-address to listen on, by specifying (for instance) \c{127.0.0.5:79}.
+In the \q{Source port} box, you can also optionally enter an \I{listen
+address}IP address to listen on, by specifying (for instance)
+\c{127.0.0.5:79}.
See \k{using-port-forwarding} for more information on how this
works and its restrictions.
-You can modify the currently active set of port forwardings in
-mid-session using \q{Change Settings}. If you delete a local or
-dynamic port forwarding in mid-session, PuTTY will stop listening
-for connections on that port, so it can be re-used by another
-program. If you delete a remote port forwarding, note that:
+In place of port numbers, you can enter \i{service names}, if they are
+known to the local system. For instance, in the \q{Destination} box,
+you could enter \c{popserver.example.com:pop3}.
+
+You can \I{port forwarding, changing mid-session}modify the currently
+active set of port forwardings in mid-session using \q{Change
+Settings} (see \k{using-changesettings}). If you delete a local or
+dynamic port forwarding in mid-session, PuTTY will stop listening for
+connections on that port, so it can be re-used by another program. If
+you delete a remote port forwarding, note that:
-\b The SSHv1 protocol contains no mechanism for asking the server to
+\b The SSH-1 protocol contains no mechanism for asking the server to
stop listening on a remote port.
-\b The SSHv2 protocol does contain such a mechanism, but not all SSH
-servers support it. (In particular, OpenSSH does not support it in
+\b The SSH-2 protocol does contain such a mechanism, but not all SSH
+servers support it. (In particular, \i{OpenSSH} does not support it in
any version earlier than 3.9.)
If you ask to delete a remote port forwarding and PuTTY cannot make
least be reasonably sure that server-side programs can no longer
access the service at your end of the port forwarding.
+If you delete a forwarding, any existing connections established using
+that forwarding remain open. Similarly, changes to global settings
+such as \q{Local ports accept connections from other hosts} only take
+effect on new forwardings.
+
+If the connection you are forwarding over SSH is itself a second SSH
+connection made by another copy of PuTTY, you might find the
+\q{logical host name} configuration option useful to warn PuTTY of
+which host key it should be expecting. See \k{config-loghost} for
+details of this.
+
\S{config-ssh-portfwd-localhost} Controlling the visibility of
forwarded ports
\cfg{winhelp-topic}{ssh.tunnels.portfwd.localhost}
The source port for a forwarded connection usually does not accept
-connections from any machine except the SSH client or server machine
-itself (for local and remote forwardings respectively). There are
-controls in the Tunnels panel to change this:
+connections from any machine except the \I{localhost}SSH client or
+server machine itself (for local and remote forwardings respectively).
+There are controls in the Tunnels panel to change this:
\b The \q{Local ports accept connections from other hosts} option
allows you to set up local-to-remote port forwardings in such a way
\b The \q{Remote ports do the same} option does the same thing for
remote-to-local port forwardings (so that machines other than the
SSH server machine can connect to the forwarded port.) Note that
-this feature is only available in the SSH 2 protocol, and not all
-SSH 2 servers support it (OpenSSH 3.0 does not, for example).
+this feature is only available in the SSH-2 protocol, and not all
+SSH-2 servers support it (\i{OpenSSH} 3.0 does not, for example).
-\S{config-ssh-portfwd-address-family} Selecting Internet protocol
-version for forwarded ports
+\S{config-ssh-portfwd-address-family} Selecting \i{Internet protocol
+version} for forwarded ports
\cfg{winhelp-topic}{ssh.tunnels.portfwd.ipversion}
-This switch allows you to select a specific Internet protocol (IPv4
-or IPv6) for the local end of a forwarded port. By default, it is
+This switch allows you to select a specific Internet protocol (\i{IPv4}
+or \i{IPv6}) for the local end of a forwarded port. By default, it is
set on \q{Auto}, which means that:
\b for a local-to-remote port forwarding, PuTTY will listen for
\b for a remote-to-local port forwarding, PuTTY will choose a
sensible protocol for the outgoing connection.
+This overrides the general Internet protocol version preference
+on the Connection panel (see \k{config-address-family}).
+
Note that some operating systems may listen for incoming connections
in IPv4 even if you specifically asked for IPv6, because their IPv4
-and IPv6 protocol stacks are linked together. Apparently Linux does
+and IPv6 protocol stacks are linked together. Apparently \i{Linux} does
this, and Windows does not. So if you're running PuTTY on Windows
and you tick \q{IPv6} for a local or dynamic port forwarding, it
will \e{only} be usable by connecting to it using IPv6; whereas if
ticking \q{Auto} should always give you a port which you can connect
to using either protocol.
-\H{config-ssh-bugs} The Bugs panel
+\H{config-ssh-bugs} \I{SSH server bugs}The Bugs panel
Not all SSH servers work properly. Various existing servers have
bugs in them, which can make it impossible for a client to talk to
\b \q{Auto}: PuTTY will use the server's version number announcement
to try to guess whether or not the server has the bug.
-\S{config-ssh-bug-ignore1} \q{Chokes on SSH1 ignore messages}
+\S{config-ssh-bug-ignore1} \q{Chokes on SSH-1 \i{ignore message}s}
\cfg{winhelp-topic}{ssh.bugs.ignore1}
An ignore message (SSH_MSG_IGNORE) is a message in the SSH protocol
which can be sent from the client to the server, or from the server
to the client, at any time. Either side is required to ignore the
-message whenever it receives it. PuTTY uses ignore messages to hide
-the password packet in SSH1, so that a listener cannot tell the
-length of the user's password; it also uses ignore messages for
-connection keepalives (see \k{config-keepalive}).
+message whenever it receives it. PuTTY uses ignore messages to
+\I{password camouflage}hide the password packet in SSH-1, so that
+a listener cannot tell the length of the user's password; it also
+uses ignore messages for connection \i{keepalives} (see
+\k{config-keepalive}).
If this bug is detected, PuTTY will stop using ignore messages. This
means that keepalives will stop working, and PuTTY will have to fall
-back to a secondary defence against SSH1 password-length
+back to a secondary defence against SSH-1 password-length
eavesdropping. See \k{config-ssh-bug-plainpw1}. If this bug is
enabled when talking to a correct server, the session will succeed,
but keepalives will not work and the session might be more
vulnerable to eavesdroppers than it could be.
-This is an SSH1-specific bug. No known SSH2 server fails to deal
-with SSH2 ignore messages.
-
-\S{config-ssh-bug-plainpw1} \q{Refuses all SSH1 password camouflage}
+\S{config-ssh-bug-plainpw1} \q{Refuses all SSH-1 \i{password camouflage}}
\cfg{winhelp-topic}{ssh.bugs.plainpw1}
-When talking to an SSH1 server which cannot deal with ignore
+When talking to an SSH-1 server which cannot deal with ignore
messages (see \k{config-ssh-bug-ignore1}), PuTTY will attempt to
disguise the length of the user's password by sending additional
padding \e{within} the password packet. This is technically a
-violation of the SSH1 specification, and so PuTTY will only do it
+violation of the SSH-1 specification, and so PuTTY will only do it
when it cannot use standards-compliant ignore messages as
camouflage. In this sense, for a server to refuse to accept a padded
password packet is not really a bug, but it does make life
inconvenient if the server can also not handle ignore messages.
-If this \q{bug} is detected, PuTTY will have no choice but to send
-the user's password with no form of camouflage, so that an
-eavesdropping user will be easily able to find out the exact length
+If this \q{bug} is detected, PuTTY will assume that neither ignore
+messages nor padding are acceptable, and that it thus has no choice
+but to send the user's password with no form of camouflage, so that
+an eavesdropping user will be easily able to find out the exact length
of the password. If this bug is enabled when talking to a correct
server, the session will succeed, but will be more vulnerable to
eavesdroppers than it could be.
-This is an SSH1-specific bug. SSH2 is secure against this type of
+This is an SSH-1-specific bug. SSH-2 is secure against this type of
attack.
-\S{config-ssh-bug-rsa1} \q{Chokes on SSH1 RSA authentication}
+\S{config-ssh-bug-rsa1} \q{Chokes on SSH-1 \i{RSA} authentication}
\cfg{winhelp-topic}{ssh.bugs.rsa1}
-Some SSH1 servers cannot deal with RSA authentication messages at
-all. If Pageant is running and contains any SSH1 keys, PuTTY will
+Some SSH-1 servers cannot deal with RSA authentication messages at
+all. If \i{Pageant} is running and contains any SSH-1 keys, PuTTY will
normally automatically try RSA authentication before falling back to
passwords, so these servers will crash when they see the RSA attempt.
server, the session will succeed, but of course RSA authentication
will be impossible.
-This is an SSH1-specific bug.
+This is an SSH-1-specific bug.
-\S{config-ssh-bug-hmac2} \q{Miscomputes SSH2 HMAC keys}
+\S{config-ssh-bug-ignore2} \q{Chokes on SSH-2 \i{ignore message}s}
+
+\cfg{winhelp-topic}{ssh.bugs.ignore2}
+
+An ignore message (SSH_MSG_IGNORE) is a message in the SSH protocol
+which can be sent from the client to the server, or from the server
+to the client, at any time. Either side is required to ignore the
+message whenever it receives it. PuTTY uses ignore messages in SSH-2
+to confuse the encrypted data stream and make it harder to
+cryptanalyse. It also uses ignore messages for connection
+\i{keepalives} (see \k{config-keepalive}).
+
+If it believes the server to have this bug, PuTTY will stop using
+ignore messages. If this bug is enabled when talking to a correct
+server, the session will succeed, but keepalives will not work and
+the session might be less cryptographically secure than it could be.
+
+\S{config-ssh-bug-hmac2} \q{Miscomputes SSH-2 HMAC keys}
\cfg{winhelp-topic}{ssh.bugs.hmac2}
Versions 2.3.0 and below of the SSH server software from
-\cw{ssh.com} compute the keys for their HMAC message authentication
-codes incorrectly. A typical symptom of this problem is that PuTTY
+\cw{ssh.com} compute the keys for their \i{HMAC} \i{message authentication
+code}s incorrectly. A typical symptom of this problem is that PuTTY
dies unexpectedly at the beginning of the session, saying
\q{Incorrect MAC received on packet}.
possible. If this bug is enabled when talking to a correct server,
communication will fail.
-This is an SSH2-specific bug.
+This is an SSH-2-specific bug.
-\S{config-ssh-bug-derivekey2} \q{Miscomputes SSH2 encryption keys}
+\S{config-ssh-bug-derivekey2} \q{Miscomputes SSH-2 \i{encryption} keys}
\cfg{winhelp-topic}{ssh.bugs.derivekey2}
-Versions below 2.0.11 of the SSH server software from \cw{ssh.com}
+Versions below 2.0.11 of the SSH server software from \i\cw{ssh.com}
compute the keys for the session encryption incorrectly. This
problem can cause various error messages, such as \q{Incoming packet
was garbled on decryption}, or possibly even \q{Out of memory}.
be possible. If this bug is enabled when talking to a correct
server, communication will fail.
-This is an SSH2-specific bug.
+This is an SSH-2-specific bug.
-\S{config-ssh-bug-sig} \q{Requires padding on SSH2 RSA signatures}
+\S{config-ssh-bug-sig} \q{Requires padding on SSH-2 \i{RSA} \i{signatures}}
\cfg{winhelp-topic}{ssh.bugs.rsapad2}
-Versions below 3.3 of OpenSSH require SSH2 RSA signatures to be
+Versions below 3.3 of \i{OpenSSH} require SSH-2 RSA signatures to be
padded with zero bytes to the same length as the RSA key modulus.
-The SSH2 draft specification says that an unpadded signature MUST be
+The SSH-2 specification says that an unpadded signature MUST be
accepted, so this is a bug. A typical symptom of this problem is
that PuTTY mysteriously fails RSA authentication once in every few
hundred attempts, and falls back to passwords.
servers usually still accept padded signatures because they're used
to talking to OpenSSH.
-This is an SSH2-specific bug.
+This is an SSH-2-specific bug.
-\S{config-ssh-bug-pksessid2} \q{Misuses the session ID in PK auth}
+\S{config-ssh-bug-pksessid2} \q{Misuses the \i{session ID} in SSH-2 PK auth}
\cfg{winhelp-topic}{ssh.bugs.pksessid2}
-Versions below 2.3 of OpenSSH require SSH2 public-key authentication
+Versions below 2.3 of \i{OpenSSH} require SSH-2 \i{public-key authentication}
to be done slightly differently: the data to be signed by the client
contains the session ID formatted in a different way. If public-key
authentication mysteriously does not work but the Event Log (see
If this bug is detected, PuTTY will sign data in the way OpenSSH
expects. If this bug is enabled when talking to a correct server,
-SSH2 public-key authentication will fail.
+SSH-2 public-key authentication will fail.
-This is an SSH2-specific bug.
+This is an SSH-2-specific bug.
-\S{config-ssh-bug-rekey} \q{Handles key re-exchange badly}
+\S{config-ssh-bug-rekey} \q{Handles SSH-2 key re-exchange badly}
\cfg{winhelp-topic}{ssh.bugs.rekey2}
-Some SSH servers cannot cope with repeat key exchange at
+Some SSH servers cannot cope with \i{repeat key exchange} at
all, and will ignore attempts by the client to start one. Since
PuTTY pauses the session while performing a repeat key exchange, the
effect of this would be to cause the session to hang after an hour
the session should still function, but may be less secure than you
would expect.
-This is an SSH2-specific bug.
+This is an SSH-2-specific bug.
+
+\S{config-ssh-bug-maxpkt2} \q{Ignores SSH-2 \i{maximum packet size}}
+
+\cfg{winhelp-topic}{ssh.bugs.maxpkt2}
+
+When an SSH-2 channel is set up, each end announces the maximum size
+of data packet that it is willing to receive for that channel. Some
+servers ignore PuTTY's announcement and send packets larger than PuTTY
+is willing to accept, causing it to report \q{Incoming packet was
+garbled on decryption}.
+
+If this bug is detected, PuTTY never allows the channel's
+\i{flow-control window} to grow large enough to allow the server to
+send an over-sized packet. If this bug is enabled when talking to a
+correct server, the session will work correctly, but download
+performance will be less than it could be.
+
+\S{config-ssh-bug-winadj} \q{Chokes on PuTTY's SSH-2 \cq{winadj} requests}
+
+\cfg{winhelp-topic}{ssh.bugs.winadj}
+
+PuTTY sometimes sends a special request to SSH servers in the middle
+of channel data, with the name \cw{winadj@putty.projects.tartarus.org}
+(see \k{sshnames-channel}). The purpose of this request is to measure
+the round-trip time to the server, which PuTTY uses to tune its flow
+control. The server does not actually have to \e{understand} the
+message; it is expected to send back a \cw{SSH_MSG_CHANNEL_FAILURE}
+message indicating that it didn't understand it. (All PuTTY needs for
+its timing calculations is \e{some} kind of response.)
+
+It has been known for some SSH servers to get confused by this message
+in one way or another \dash because it has a long name, or because
+they can't cope with unrecognised request names even to the extent of
+sending back the correct failure response, or because they handle it
+sensibly but fill up the server's log file with pointless spam, or
+whatever. PuTTY therefore supports this bug-compatibility flag: if it
+believes the server has this bug, it will never send its
+\cq{winadj@putty.projects.tartarus.org} request, and will make do
+without its timing data.
+
+\H{config-serial} The Serial panel
+
+The \i{Serial} panel allows you to configure options that only apply
+when PuTTY is connecting to a local \I{serial port}\i{serial line}.
+
+\S{config-serial-line} Selecting a serial line to connect to
+
+\cfg{winhelp-topic}{serial.line}
+
+The \q{Serial line to connect to} box allows you to choose which
+serial line you want PuTTY to talk to, if your computer has more
+than one serial port.
+
+On Windows, the first serial line is called \i\cw{COM1}, and if there
+is a second it is called \cw{COM2}, and so on.
+
+This configuration setting is also visible on the Session panel,
+where it replaces the \q{Host Name} box (see \k{config-hostname}) if
+the connection type is set to \q{Serial}.
+
+\S{config-serial-speed} Selecting the speed of your serial line
+
+\cfg{winhelp-topic}{serial.speed}
+
+The \q{Speed} box allows you to choose the speed (or \q{baud rate})
+at which to talk to the serial line. Typical values might be 9600,
+19200, 38400 or 57600. Which one you need will depend on the device
+at the other end of the serial cable; consult the manual for that
+device if you are in doubt.
+
+This configuration setting is also visible on the Session panel,
+where it replaces the \q{Port} box (see \k{config-hostname}) if the
+connection type is set to \q{Serial}.
+
+\S{config-serial-databits} Selecting the number of data bits
+
+\cfg{winhelp-topic}{serial.databits}
+
+The \q{Data bits} box allows you to choose how many data bits are
+transmitted in each byte sent or received through the serial line.
+Typical values are 7 or 8.
+
+\S{config-serial-stopbits} Selecting the number of stop bits
+
+\cfg{winhelp-topic}{serial.stopbits}
+
+The \q{Stop bits} box allows you to choose how many stop bits are
+used in the serial line protocol. Typical values are 1, 1.5 or 2.
+
+\S{config-serial-parity} Selecting the serial parity checking scheme
+
+\cfg{winhelp-topic}{serial.parity}
+
+The \q{Parity} box allows you to choose what type of parity checking
+is used on the serial line. The settings are:
+
+\b \q{None}: no parity bit is sent at all.
+
+\b \q{Odd}: an extra parity bit is sent alongside each byte, and
+arranged so that the total number of 1 bits is odd.
+
+\b \q{Even}: an extra parity bit is sent alongside each byte, and
+arranged so that the total number of 1 bits is even.
+
+\b \q{Mark}: an extra parity bit is sent alongside each byte, and
+always set to 1.
+
+\b \q{Space}: an extra parity bit is sent alongside each byte, and
+always set to 0.
+
+\S{config-serial-flow} Selecting the serial flow control scheme
+
+\cfg{winhelp-topic}{serial.flow}
+
+The \q{Flow control} box allows you to choose what type of flow
+control checking is used on the serial line. The settings are:
+
+\b \q{None}: no flow control is done. Data may be lost if either
+side attempts to send faster than the serial line permits.
+
+\b \q{XON/XOFF}: flow control is done by sending XON and XOFF
+characters within the data stream.
+
+\b \q{RTS/CTS}: flow control is done using the RTS and CTS wires on
+the serial line.
+
+\b \q{DSR/DTR}: flow control is done using the DSR and DTR wires on
+the serial line.
-\H{config-file} Storing configuration in a file
+\H{config-file} \ii{Storing configuration in a file}
PuTTY does not currently support storing its configuration in a file
-instead of the Registry. However, you can work around this with a
-couple of batch files.
+instead of the \i{Registry}. However, you can work around this with a
+couple of \i{batch file}s.
You will need a file called (say) \c{PUTTY.BAT} which imports the
contents of a file into the Registry, then runs PuTTY, exports the
~mdw / sgt / putty / blobdiff