+\versionid $Id: config.but,v 1.50 2003/01/16 15:43:18 jacob Exp $
+
\C{config} Configuring PuTTY
This chapter describes all the 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
-session, by selecting \e{Change Settings} from the window menu.
+session, by selecting \q{Change Settings} from the window menu.
\H{config-session} The Session panel
\S{config-hostname} The host name section
+\cfg{winhelp-topic}{session.hostname}
+
The top box on the Session panel, labelled \q{Specify your
connection by host name}, contains the details that need to be
filled in before PuTTY can open a session at all.
-\b The \e{Host Name} box is where you type the name, or the IP
+\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 \e{Protocol} radio buttons let you choose what type of
-connection you want to make: a raw connection, a Telnet connection,
-or an SSH connection. \#{ FIXME: link to sections on these? }
+\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.)
-\b The \e{Port} box lets you specify which port number on the server
-to connect to. If you select Telnet 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 \e{Port} box.
+\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 (see \k{using-rawprot}), you will almost certainly need to fill
+in the \q{Port} box.
\S{config-saving} Loading and storing saved sessions
+\cfg{winhelp-topic}{session.saved}
+
The next part of the Session configuration panel allows you to save
your preferred PuTTY options so they will appear automatically the
next time you start PuTTY. It also allows you to create \e{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
-click. Then press the \e{Save} button.
+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.
\b To save a session: first go through the rest of the configuration
box setting up all the options you want. Then come back to the
-Session panel. Enter a name for the saved session in the \e{Saved
+Session panel. Enter a name for the saved session in the \q{Saved
Sessions} input box. (The server name is often a good choice for a
-saved session name.) Then press the \e{Save} button. Your saved
+saved session name.) Then press the \q{Save} button. Your saved
session name should now appear in the list box.
\b To reload a saved session: single-click to select the session
-name in the list box, and then press the \e{Load} button. Your saved
+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,
single-click to select the session name in the list box, and press
-the \e{Save} button. The new settings will be saved over the top of
+the \q{Save} button. The new settings will be saved over the top of
the old ones.
\b To start a saved session immediately: double-click on the session
name in the list box.
\b To delete a saved session: single-click to select the session
-name in the list box, and then press the \e{Delete} button.
+name in the list box, and then press the \q{Delete} button.
Each saved session is independent of the Default Settings
configuration. If you change your preferences and update Default
\S{config-closeonexit} \q{Close Window on Exit}
-Finally in the Session panel, there is a check box labelled \q{Close
-Window on Exit}. If this is turned on, the PuTTY session window will
-disappear as soon as the session inside it terminates. Otherwise,
-the window will remain on the desktop until you close it yourself,
-so you can still read and copy text out of it.
+\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
+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, you should arrange this option to be off.
+
+\q{Close Window On Exit} has three settings. \q{Always} means always
+close the window on exit; \q{Never} means never close on exit
+(always leave the window open). The third setting, and the default
+one, is \q{Only on clean exit}. In this mode, a session which
+terminates normally will cause its window to close, but one which is
+aborted unexpectedly by network trouble or a confusing message from
+the server will leave the window up.
+
+\H{config-logging} The Logging panel
+
+\cfg{winhelp-topic}{logging.main}
+
+The Logging configuration panel allows you to save log files 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
+
+\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{Log printable output only}. 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
+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
+you are experiencing problems with PuTTY's terminal handling: you
+can record everything that went to the terminal, so that someone
+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 will appear in the log file, so be sure to
+edit it out before sending the log file to anyone else!
+
+\S{config-logfilename} \q{Log file name}
+
+\cfg{winhelp-topic}{logging.filename}
+
+In this edit box you enter the name of the file you want to log the
+session to. The \q{Browse} button will let you look around your file
+system to find the right place to put the file; or if you already
+know exactly where you want it to go, you can just type a pathname
+into the edit box.
+
+There are a few special features in this box. If you use the \c{&}
+character in the file name box, PuTTY will insert details of the
+current session in the name of the file it actually opens. The
+precise replacements it will do are:
+
+\b \c{&Y} will be replaced by the current year, as four digits.
+
+\b \c{&M} will be replaced by the current month, as two digits.
+
+\b \c{&D} will be replaced by the current day of the month, as two
+digits.
+
+\b \c{&T} will be replaced by the current time, as six digits
+(HHMMSS) with no punctuation.
+
+\b \c{&H} will be replaced by the host name you are connecting to.
+
+For example, if you enter the host name
+\c{c:\\puttylogs\\log-&h-&y&m&d-&t.dat}, you will end up with files looking
+like
+
+\c log-server1.example.com-20010528-110859.dat
+\c log-unixbox.somewhere.org-20010611-221001.dat
+
+\S{config-logfileexists} \q{What to do if the log file already exists}
+
+\cfg{winhelp-topic}{logging.exists}
+
+This control allows you to specify what PuTTY should do if it tries
+to start writing to a log file and it finds the file already exists.
+You might want to automatically destroy the existing log file and
+start a new one with the same name. Alternatively, you might want to
+open the existing log file and add data to the \e{end} of it.
+Finally (the default option), you might not want to have any
+automatic behaviour, but to ask the user every time the problem
+comes up.
\H{config-terminal} The Terminal panel
\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
window reaches the right-hand edge of the window.
could try turning this option off.
Auto wrap mode can be turned on and off by control sequences sent by
-the server. This configuration option only controls the \e{default}
-state. If you modify this option in mid-session using \e{Change
-Settings}, you will need to reset the terminal \#{ FIXME } before
-the change takes effect.
+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-decom} \q{DEC Origin Mode initially on}
+\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.
like the wrong part of the screen, you could try turning DEC Origin
Mode on to see whether that helps.
-DEC Origin Mode can be turned on and off by control sequences sent by
-the server. This configuration option only controls the \e{default}
-state. If you modify this option in mid-session using \e{Change
-Settings}, you will need to reset the terminal \#{ FIXME } before
-the change takes effect.
+DEC Origin Mode can be turned on and off by 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-crlf} \q{Implicit CR in every LF}
+\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
left-hand side of the screen. The LF character makes the cursor move
\c Second line
\c Third line
-\S{config-beep} \q{Beep enabled}
-
-This option lets you turn off beeps in PuTTY. If your server is
-beeping too much or attracting unwelcome attention, you can turn the
-beeps off.
-
\S{config-erase} \q{Use 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
screen should always be cleared to the \e{default} background
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
+\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}
+\cfg{winhelp-topic}{terminal.blink}
+
The server can ask PuTTY to display text that blinks on and off.
This is very distracting, so PuTTY allows you to turn blinking text
off completely.
-\S{config-localterm} \q{Use local terminal line discipline}
+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.
-Normally, every character you type into the PuTTY window is sent
-straight to the server.
+Blinking text can be turned on and off by 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-answerback} \q{Answerback to ^E}
+
+\cfg{winhelp-topic}{terminal.answerback}
-If you enable local terminal line discipline, this changes. PuTTY
-will let you edit a whole line at a time locally, and the line will
-only be sent to the server when you press Return. If you make a
-mistake, you can use the Backspace key to correct it before you
-press Return, and the server will never see the mistake.
+This option controls what PuTTY will send back to the server if the
+server sends it the ^E enquiry character. Normally it just sends
+the string \q{PuTTY}.
-Since it would be hard to edit a line locally without being able to
-see it, local terminal line discipline also makes PuTTY echo what
-you type. This makes it ideal for use in raw mode \#{ FIXME } or
-when connecting to MUDs or talkers.
+If you accidentally write the contents of a binary file to your
+terminal, you will probably find that it contains more than one ^E
+character, and as a result your next command line will probably read
+\q{PuTTYPuTTYPuTTY...} as if you had typed the answerback string
+multiple times at the keyboard. If you set the answerback string to
+be empty, this problem should go away, but doing so might cause
+other problems.
-\S{config-logging} Controlling session logging
+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
+\k{config-termtype} for details.
-PuTTY has the ability to log the output from your session into a
-file. You might want this if you were saving a particular piece of
-output to mail to somebody, for example in a bug report.
+You can include control characters in the answerback string using
+\c{^C} notation. (Use \c{^~} to get a literal \c{^}.)
-You can choose between:
+\S{config-localecho} \q{Local echo}
-\b not logging anything (the default)
+\cfg{winhelp-topic}{terminal.localecho}
-\b logging only the printable characters in a session (ignoring
-control sequences to change colours or clear the screen)
+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.)
-\b logging everything sent to the terminal by the server.
+Some types of session need local echo, and many do not. In its
+default mode, PuTTY will automatically attempt to deduce whether or
+not local echo is appropriate for the session you are working in. If
+you find it has made the wrong decision, you can use this
+configuration option to override its choice: you can force local
+echo to be turned on, or force it to be turned off, instead of
+relying on the automatic detection.
-You can turn logging on and off in mid-session using \e{Change
-Settings}.
+\S{config-localedit} \q{Local line editing}
+
+\cfg{winhelp-topic}{terminal.localedit}
+
+Normally, every character you type into the PuTTY window is sent
+immediately to the server the moment you type it.
+
+If you enable local line editing, this changes. PuTTY will let you
+edit a whole line at a time locally, and the line will only be sent
+to the server when you press Return. If you make a mistake, you can
+use the Backspace key to correct it before you press Return, and the
+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
+(\k{config-localecho}). This makes it ideal for use in raw mode
+\#{FIXME} or when connecting to MUDs or talkers. (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.)
+
+Some types of session need local line editing, and many do not. In
+its default mode, PuTTY will automatically attempt to deduce whether
+or not local line editing is appropriate for the session you are
+working in. If you find it has made the wrong decision, you can use
+this configuration option to override its choice: you can force
+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
+
+\cfg{winhelp-topic}{terminal.printing}
+
+A lot of VT100-compatible terminals support printing under control
+of the remote server. PuTTY supports this feature as well, but it is
+turned off by default.
+
+To enable remote-controlled printing, choose a printer from the
+\q{Printer to send ANSI printer output to} drop-down list box. This
+should allow you to select from all the printers you have installed
+drivers for on your computer. Alternatively, you can type the
+network name of a networked printer (for example,
+\c{\\\\printserver\\printer1}) even if you haven't already
+installed a driver for it on your own machine.
+
+When the remote server attempts to print some data, PuTTY will send
+that data to the printer \e{raw} - without translating it,
+attempting to format it, or doing anything else to it. It is up to
+you to ensure your remote server knows what type of printer it is
+talking to.
+
+Since PuTTY sends data to the printer raw, it cannot offer options
+such as portrait versus landscape, print quality, or paper tray
+selection. All these things would be done by your PC printer driver
+(which PuTTY bypasses); if you need them done, you will have to find
+a way to configure your remote server to do them.
+
+To disable remote printing again, choose \q{None (printing
+disabled)} from the printer selection list. This is the default
+state.
\H{config-keyboard} The Keyboard panel
\S{config-backspace} Changing the action of the 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
believe that the Backspace key should send ASCII code 127 (usually
\S{config-homeend} Changing the action of the Home and End keys
+\cfg{winhelp-topic}{keyboard.homeend}
+
The Unix terminal emulator \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.
\S{config-funkeys} Changing the action of the function keys and keypad
+\cfg{winhelp-topic}{keyboard.funkeys}
+
This option affects the function keys (F1 to F12) and the top row of
the numeric keypad.
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
+\c{ESC O[}
+
+\b In 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
+\c{ESC [w} through to \c{ESC [\{}.
+
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
+\cfg{winhelp-topic}{keyboard.appcursor}
+
Application Cursor Keys mode is a way for the server to change the
control sequences sent by the arrow keys. In normal mode, the arrow
keys send \c{ESC [A} through to \c{ESC [D}. In application mode,
Application Cursor Keys mode can be turned on and off by the server,
depending on the application. PuTTY allows you to configure the
-initial state, and also allows you to disable application mode
-completely.
+initial state.
+
+You can also disable application cursor keys mode completely, using
+the \q{Features} configuration panel; see
+\k{config-features-application}.
\S{config-appkeypad} Controlling Application Keypad mode
+\cfg{winhelp-topic}{keyboard.appkeypad}
+
Application Keypad mode is a way for the server to change the
behaviour of the numeric keypad.
Application keypad mode can be turned on and off by the server,
depending on the application. PuTTY allows you to configure the
-initial state, and also allows you to disable application mode
-completely.
+initial state.
+
+You can also disable application keypad mode completely, using the
+\q{Features} configuration panel; see
+\k{config-features-application}.
\S{config-nethack} Using NetHack keypad mode
+\cfg{winhelp-topic}{keyboard.nethack}
+
PuTTY has a special mode for playing NetHack. You can enable it by
selecting \q{NetHack} in the \q{Initial state of numeric keypad}
control.
\S{config-compose} Enabling a DEC-like 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
two more characters. The two characters are \q{combined} to produce
easy to remember; for example, composing \q{e} and \q{`} produces
the \q{\u00e8{e-grave}} character.
-If you enable the \q{Application and AltGr act as Compose key}
-option, the Windows Application key and the AltGr key will both have
-this behaviour.
+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
+Compose key} option, the AltGr key will become a Compose key.
+
+\S{config-ctrlalt} \q{Control-Alt is different from AltGr}
+
+\cfg{winhelp-topic}{keyboard.ctrlalt}
+
+Some old keyboards do not have an AltGr key, which can make it
+difficult to type some characters. PuTTY can be configured to treat
+the key combination Ctrl + Left Alt the same way as the AltGr key.
+
+By default, this checkbox is checked, and the key combination Ctrl +
+Left Alt does something completely different. PuTTY's usual handling
+of the left Alt key is to prefix the Escape (Control-\cw{[})
+character to whatever character sequence the rest of the keypress
+would generate. For example, Alt-A generates Escape followed by
+\c{a}. So Alt-Ctrl-A would generate Escape, followed by Control-A.
+
+If you uncheck this box, Ctrl-Alt will become a synonym for AltGr,
+so you can use it to type extra graphic characters if your keyboard
+has any.
+
+(However, Ctrl-Alt will never act as a Compose key, regardless of the
+setting of \q{AltGr acts as Compose key} described in
+\k{config-compose}.)
+
+\H{config-bell} The Bell panel
+
+The Bell panel controls the 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
+feature to do; the Bell panel allows you to configure alternative
+actions.
+
+\S{config-bellstyle} \q{Set the style of bell}
+
+\cfg{winhelp-topic}{bell.style}
+
+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 \q{Play Windows Default 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{Play a custom 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}.
+
+\b \q{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.
+
+\S{config-belltaskbar} \q{Taskbar/caption indication on bell}
+
+\cfg{winhelp-topic}{bell.taskbar}
+
+This feature controls what happens to the PuTTY window's entry in
+the Windows Taskbar if a bell occurs while the window does not have
+the input focus.
+
+In the default state (\q{Disabled}) nothing unusual happens.
+
+If you select \q{Steady}, then when a bell occurs and the window is
+not in focus, the window's Taskbar entry and its title bar will
+change colour to let you know that PuTTY session is asking for your
+attention. The change of colour will persist until you select the
+window, so you can leave several PuTTY windows minimised in your
+terminal, go away from your keyboard, and be sure not to have missed
+any important beeps when you get back.
+
+\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}
+
+\cfg{winhelp-topic}{bell.overload}
+
+A common user error in a terminal session is to accidentally run the
+Unix command \c{cat} (or equivalent) on an inappropriate file type,
+such as an executable, image file, or ZIP file. This produces a huge
+stream of non-text characters sent to the terminal, which typically
+includes a lot of bell characters. As a result of this the terminal
+often doesn't stop beeping for ten minutes, and everybody else in
+the office gets annoyed.
+
+To try to avoid this behaviour, or any other cause of excessive
+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.
+
+If you want this feature completely disabled, you can turn it off
+using the checkbox \q{Bell is temporarily disabled when over-used}.
+
+Alternatively, if you like the bell overload feature but don't agree
+with the settings, you can configure the details: how many bells
+constitute an overload, how short a time period they have to arrive
+in to do so, and how much silent time is required before the
+overload feature will deactivate itself.
+
+Bell overload mode is always deactivated by any keypress in the
+terminal. This means it can respond to large unexpected streams of
+data, but does not interfere with ordinary command-line activities
+that generate beeps (such as filename completion).
+
+\H{config-features} The Features panel
+
+PuTTY's 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.
+
+The Features configuration panel allows you to disable some of
+PuTTY's more advanced terminal features, in case they cause trouble.
+
+\S{config-features-application} Disabling application keypad and cursor keys
+
+\cfg{winhelp-topic}{features.application}
+
+Application keypad mode (see \k{config-appkeypad}) and 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
+
+\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.
+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).
+
+If you find this feature inconvenient, you can disable it using the
+\q{Disable xterm-style mouse reporting} control. With this box
+ticked, the mouse will \e{always} do copy and paste in the normal
+way.
+
+Note that even if the application takes over the mouse, you can
+still manage PuTTY's copy and paste by holding down the Shift key
+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
+
+\cfg{winhelp-topic}{features.resize}
+
+PuTTY has the ability to change the terminal's size and position in
+response to commands from the server. If you find PuTTY is doing
+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
+
+\cfg{winhelp-topic}{features.altscreen}
+
+Many terminals, including PuTTY, support an \q{alternate screen}.
+This is the same size as the ordinary terminal screen, but separate.
+Typically a screen-based program such as a text editor might switch
+the terminal to the alternate screen before starting up. Then at the
+end of the run, it switches back to the primary screen, and you see
+the screen contents just as they were before starting the editor.
+
+Some people prefer this not to happen. If you want your editor to
+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
+
+\cfg{winhelp-topic}{features.retitle}
+
+PuTTY has the ability to change the window title in response to
+commands from the server. If you find PuTTY is doing this
+unexpectedly or inconveniently, you can tell PuTTY not to respond to
+those server commands.
+
+\S{config-features-dbackspace} Disabling destructive backspace
+
+\cfg{winhelp-topic}{features.dbackspace}
+
+Normally, when PuTTY receives character 127 (^?) from the server, it
+will perform a \q{destructive backspace}: move the cursor one space
+left and delete the character under it. This can apparently cause
+problems in some applications, so PuTTY provides the ability to
+configure character 127 to perform a normal backspace (without
+deleting a character) instead.
+
+\S{config-features-charset} Disabling remote 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
+IRC client) seems to have a habit of reconfiguring the character set
+to something other than the user intended.
+
+If you find that accented characters are not showing up the way you
+expect them to, particularly if you're running BitchX, you could try
+disabling the remote character set configuration commands.
\H{config-window} The Window panel
The Window configuration panel allows you to control aspects of the
-PuTTY window and its behaviour.
+PuTTY window.
\S{config-winsize} Setting the size of the PuTTY window
-The \e{Rows} and \e{Columns} boxes let you set the PuTTY window to a
+\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.
-If you are running an application which is unable to deal with
-changes in window size, you might want to enable the \q{Lock window
-size against resizing} option, which prevents the user from
-accidentally changing the size of the window.
+\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.
+
+When you resize the PuTTY window, one of four things can happen:
+
+\b Nothing (if you have completely disabled resizes).
+
+\b The font size can stay the same and the number of rows and
+columns in the terminal can change.
+
+\b The number of rows and columns in the terminal can stay the same,
+and the font size can change.
+
+\b You can allow PuTTY to change \e{either} the terminal size or the
+font size. In this mode it will change the terminal size most of the
+time, but enlarge the font when you maximise the window.
+
+You can control which of these happens using the \q{Lock terminal
+size against resizing} and \q{Lock font size against resizing}
+options. If you lock both, the window will refuse to be resized at
+all. If you lock just the terminal size, the font size will change
+when you resize the window. If you lock just the font size, the
+terminal size will change when you resize the window.
\S{config-scrollback} Controlling scrollback
-Text that scrolls off the top of the PuTTY terminal window is kept
-for reference. The scrollbar on the right of the window lets you
-view the scrolled-off text. You can also page through the scrollback
-using the keyboard, by pressing Shift-PgUp and Shift-PgDn.
+\cfg{winhelp-topic}{window.scrollback}
+
+These options let you configure the way PuTTY keeps text after it
+scrolls off the top of the screen (see \k{using-scrollback}).
The \q{Lines of scrollback} box lets you configure how many lines of
-text PuTTY keeps. The \q{Display scrollbar} option allows you to
+text PuTTY keeps. The \q{Display scrollbar} options allow you to
hide the scrollbar (although you can still view the scrollback using
-Shift-PgUp and Shift-PgDn).
+Shift-PgUp and Shift-PgDn). You can separately configure whether the
+scrollbar is shown in full-screen mode and in normal modes.
If you are viewing part of the scrollback when the server sends more
text to PuTTY, the screen will revert to showing the current
screen revert when you press a key, by turning on \q{Reset
scrollback on keypress}.
+\H{config-appearance} The Appearance panel
+
+The Appearance configuration panel allows you to control aspects of
+the appearance of PuTTY's window.
+
+\S{config-cursor} Controlling the appearance of the cursor
+
+\cfg{winhelp-topic}{appearance.cursor}
+
+The \q{Cursor appearance} option lets you configure the cursor to be
+a block, an underline, or a vertical line. A block cursor becomes an
+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
+works in any of the cursor modes.
+
+\S{config-font} Controlling the 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.)
+
+\S{config-title} Controlling the 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
+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
+modify the title of the window in mid-session. There is also an
+\c{xterm} sequence to modify the 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
+applicable. By default PuTTY's window title and Taskbar caption will
+change into the server-supplied icon title if you 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.) By checking the box marked
+\q{Avoid ever using icon title}, you can arrange that PuTTY will
+always display the window title, and completely ignore any icon
+titles the server sends it.
+
+\S{config-mouseptr} \q{Hide mouse pointer when typing in window}
+
+\cfg{winhelp-topic}{appearance.hidemouse}
+
+If you enable this option, the mouse pointer will disappear if the
+PuTTY window is selected and you press a key. This way, it will not
+obscure any of the text in the window while you work in your
+session. As soon as you move the mouse, the pointer will reappear.
+
+This option is disabled by default, so the mouse pointer remains
+visible at all times.
+
+\S{config-winborder} Controlling the window border
+
+\cfg{winhelp-topic}{appearance.border}
+
+PuTTY allows you to configure the appearance of the window border to
+some extent.
+
+The checkbox marked \q{Sunken-edge border} changes the appearance of
+the window border to something more like a DOS box: the inside edge
+of the border is highlighted as if it sank down to meet the surface
+inside the window. This makes the border a little bit thicker as
+well. It's hard to describe well. Try it and see if you like it.
+
+You can also configure a completely blank gap between the text in
+the window and the border, using the \q{Gap between text and window
+edge} control. By default this is set at one pixel. You can reduce
+it to zero, or increase it further.
+
+\H{config-behaviour} The Behaviour panel
+
+The Behaviour configuration panel allows you to control aspects of
+the behaviour of PuTTY's window.
+
\S{config-warnonclose} \q{Warn before closing window}
+\cfg{winhelp-topic}{behaviour.closewarn}
+
If you press the 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
\S{config-altf4} \q{Window closes on 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
\S{config-altspace} \q{System menu appears on ALT-Space}
+\cfg{winhelp-topic}{behaviour.altspace}
+
If this option is enabled, then pressing ALT-Space will bring up the
PuTTY window's menu, like clicking on the top left corner. If it is
disabled, then pressing ALT-Space will just send \c{ESC SPACE} to
the server.
+Some 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
+system menu via voice, and to close, minimise, maximise and restore
+the window.
+
\S{config-altonly} \q{System menu appears on Alt alone}
+\cfg{winhelp-topic}{behaviour.altonly}
+
If this option is enabled, then pressing and releasing ALT will
bring up the PuTTY window's menu, like clicking on the top left
corner. If it is disabled, then pressing and releasing ALT will have
\S{config-alwaysontop} \q{Ensure window is always on top}
+\cfg{winhelp-topic}{behaviour.alwaysontop}
+
If this option is enabled, the PuTTY window will stay on top of all
other windows.
-\H{config-appearance} The Appearance panel
+\S{config-fullscreen} \q{Full screen on Alt-Enter}
-The Appearance configuration panel allows you to control aspects of
-PuTTY's appearance.
+\cfg{winhelp-topic}{behaviour.altenter}
-\S{config-cursor} Controlling the appearance of the cursor
-
-\# this will look considerably less silly when we bring in
-\# underline-versus-block-versus-vertical-line cursor configuration
-\# and also allow the cursor to vanish on keypress a la Word. Until
-\# then, this box does look silly with only one thing in it. Deal.
+If this option is enabled, then pressing Alt-Enter will cause the
+PuTTY window to become full-screen. Pressing Alt-Enter again will
+restore the previous window size.
-\S{config-font} Controlling the font used in the terminal window
-
-\S{config-title} Controlling the window title
+The full-screen feature is also available from the 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
translation between the character set understood by the server and
the character set understood by PuTTY.
-\S{config-linedraw} Line drawing characters
+\S{config-charset} Controlling character set translation
+
+\cfg{winhelp-topic}{translation.codepage}
+
+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.
+
+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.
+
+A few notable character sets are:
+
+\b The 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
+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.
-\S{config-outputtrans} Character set translation of output data
+If you need support for a numeric code page which is not listed in
+the drop-down list, such as code page 866, then you should be able
+to enter its name manually (\c{CP866} for example) in the list box
+and get the right result.
-\S{config-inputtrans} Character set translation of input data
+\S{config-cyr} \q{Caps Lock acts as 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
+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
+
+\cfg{winhelp-topic}{translation.linedraw}
+
+VT100-series terminals allow the server to send control sequences
+that shift temporarily into a separate character set for drawing
+lines and boxes. PuTTY has a variety of ways to support this
+capability. In general you should probably try lots of options until
+you find one that your particular font supports.
+
+\b \q{Font has XWindows encoding} is for use with fonts that have a
+special encoding, where the lowest 32 character positions (below the
+ASCII printable range) contain the line-drawing characters. This is
+unlikely to be the case with any standard Windows font; it will
+probably only apply to custom-built fonts or fonts that have been
+automatically converted from the X Window System.
+
+\b \q{Use font in both ANSI and OEM modes} tries to use the same
+font in two different character sets, to obtain a wider range of
+characters. This doesn't always work; some fonts claim to be a
+different size depending on which character set you try to use.
+
+\b \q{Use font in OEM mode only} is more reliable than that, but can
+miss out other characters from the main character set.
+
+\b \q{Poor man's line drawing} assumes that the font \e{cannot}
+generate the line and box characters at all, so it will use the
+\c{+}, \c{-} and \c{|} characters to draw approximations to boxes.
+You should use this option if none of the other options works.
+
+\b \q{Unicode mode} tries to use the box characters that are present
+in Unicode. For good Unicode-supporting fonts this is probably the
+most reliable and functional option.
\H{config-selection} The Selection panel
The Selection panel allows you to control the way copy and paste
work in the PuTTY window.
+\S{config-linedrawpaste} Controlling the pasting 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 translate
+them into the \q{poor man's} line-drawing characters \c{+}, \c{-}
+and \c{|}. The checkbox \q{Don't translate line drawing chars}
+disables this feature, so line-drawing characters will be pasted as
+if they were in the normal character set. 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 layout in another program, for
+example.
+
+\S{config-rtfpaste} Pasting in 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
+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.
+
+This option can easily be inconvenient, so by default it is
+disabled.
+
\S{config-mouse} Changing the actions of the mouse buttons
+\cfg{winhelp-topic}{selection.buttons}
+
+PuTTY's copy and paste mechanism is 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.
+
+Windows typically only has two mouse buttons, so in PuTTY's default
+configuration, the \e{right} button pastes, and the \e{middle}
+button (if you have one) extends a selection.
+
+If you have a 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.
+
+\S{config-mouseshift} \q{Shift overrides application's use of mouse}
+
+\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.
+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).
+
+When running one of these applications, pressing the mouse buttons
+no longer performs copy and paste. If you do need to copy and paste,
+you can still do so if you hold down Shift while you do your mouse
+clicks.
+
+However, it is possible in theory for applications to even detect
+and make use of Shift + mouse clicks. We don't know of any
+applications that do this, but in case someone ever writes one,
+unchecking the \q{Shift overrides application's use of mouse}
+checkbox will cause Shift + mouse clicks to go to the server as well
+(so that mouse-driven copy and paste will be completely disabled).
+
+If you want to prevent the application from taking over the mouse at
+all, you can do this using the Features control panel; see
+\k{config-features-mouse}.
+
+\S{config-rectselect} Default selection mode
+
+\cfg{winhelp-topic}{selection.rect}
+
+As described in \k{using-selection}, PuTTY has two modes of
+selecting text to be copied to the clipboard. In the default mode
+(\q{Normal}), dragging the mouse from point A to point B selects to
+the end of the line containing A, all the lines in between, and from
+the very beginning of the line containing B. In the other mode
+(\q{Rectangular block}), dragging the mouse between two points
+defines a rectangle, and everything within that rectangle is copied.
+
+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
+you have to hold down Alt to get the \e{normal} behaviour.
+
\S{config-charclasses} Configuring 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
+precisely what is considered to be a word.
+
+Each character is given a \e{class}, which is a small number
+(typically 0, 1 or 2). PuTTY considers a single word to be any
+number of adjacent characters in the same class. So by modifying the
+assignment of characters to classes, you can modify the word-by-word
+selection behaviour.
+
+In the default configuration, the character classes are:
+
+\b Class 0 contains white space and control characters.
+
+\b Class 1 contains most punctuation.
+
+\b Class 2 contains letters, numbers and a few pieces of punctuation
+(the double quote, minus sign, period, forward slash and
+underscore).
+
+So, for example, if you assign the \c{@} symbol into character class
+2, you will be able to select an e-mail address with just a double
+click.
+
+In order to adjust these assignments, you start by selecting a group
+of characters in the list box. Then enter a class number in the edit
+box below, and press the \q{Set} button.
+
+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
+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.
+
\H{config-colours} The Colours panel
The Colours panel allows you to control PuTTY's use of colour.
\S{config-boldcolour} \q{Bolded text is a different colour}
+\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.
+
+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.
+
\S{config-logpalette} \q{Attempt to use 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
+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-colourcfg} Adjusting the colours in the 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
+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).
+In addition, if you have selected \q{Bolded text is a different
+colour}, you can also modify the precise shades used for the bold
+versions of these colours.
+
\H{config-connection} The Connection panel
The Connection panel allows you to configure options that apply to
\S{config-termtype} \q{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
+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.
+
+PuTTY attempts to emulate the Unix \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
+terminal reports \q{Unknown terminal type} - you could try setting
+this to something different, such as \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-username} \q{Auto-login username}
+\cfg{winhelp-topic}{connection.username}
+
+All three of the SSH, Telnet and Rlogin protocols allow you to
+specify what user name you want to log in as, without having to type
+it explicitly every time. (Some Telnet servers don't support this.)
+
+In this box you can type that user name.
+
\S{config-keepalive} Using keepalives to prevent disconnection
+\cfg{winhelp-topic}{connection.keepalive}
+
+If you find your sessions are closing unexpectedly (\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
+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
+unexpectedly closed by the firewall if no traffic is seen in the
+session for some time.
+
+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,
+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
+seconds (5 minutes) in the box.
+
+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
+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
+will notice that anything was wrong. However, if one side does send
+something during the break, it will repeatedly try to re-send, and
+eventually give up and abandon the connection. Then when
+connectivity is restored, the other side will find that the first
+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
+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.
+
+Keepalives are only supported in Telnet and SSH; the Rlogin and Raw
+protocols offer no way of implementing them.
+
+Note that if you are using SSH1 and the server has a bug that makes
+it unable to deal with SSH1 ignore messages (see
+\k{config-ssh-bug-ignore1}), enabling keepalives will have no effect.
+
+\S{config-nodelay} \q{Disable 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
+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.
+
+\H{config-proxy} The Proxy panel
+
+\cfg{winhelp-topic}{proxy.main}
+
+The 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}).
+
+\S{config-proxy-type} Setting the proxy type
+
+\cfg{winhelp-topic}{proxy.type}
+
+The \q{Proxy type} radio buttons allow you to configure what type of
+proxy you want PuTTY to use for its network connections. The default
+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
+in \W{http://www.ietf.org/rfc/rfc2817.txt}{RFC 2817}.
+
+\b Selecting \q{SOCKS} allows you to proxy your connections through
+a 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.
+
+\S{config-proxy-exclude} Excluding parts of the network from proxying
+
+\cfg{winhelp-topic}{proxy.exclude}
+
+Typically you will only need to use a proxy to connect to non-local
+parts of your network; for example, your proxy might be required for
+connections outside your company's internal network. In the
+\q{Exclude Hosts/IPs} box you can enter ranges of IP addresses, or
+ranges of DNS names, for which PuTTY will avoid using the proxy and
+make a direct connection instead.
+
+The \q{Exclude Hosts/IPs} box may contain more than one exclusion
+range, separated by commas. Each range can be an IP address or a DNS
+name, with a \c{*} character allowing wildcards. For example:
+
+\c *.example.com
+
+This excludes any host with a name ending in \c{.example.com} from
+proxying.
+
+\c 192.168.88.*
+
+This excludes any host with an IP address starting with 192.168.88
+from proxying.
+
+\c 192.168.88.*,*.example.com
+
+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
+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
+\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
+
+\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
+(on the client machine) or performed by the proxy.
+
+The \q{Do DNS name lookup at proxy end} configuration option allows
+you to control this. If you set it to \q{No}, PuTTY will always do
+its own DNS, and will always pass an IP address to the proxy. If you
+set it to \q{Yes}, PuTTY will always pass host names straight to the
+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.
+
+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
+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.
+
+The original SOCKS 4 protocol does not support proxy-side DNS. There
+is a protocol extension (SOCKS 4A) which does support it, but not
+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
+
+\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.
+
+Authentication is not supported for all forms of proxy:
+
+\b Username and password authentication is supported for HTTP
+proxies and SOCKS 5 proxies.
+
+\b SOCKS 4 can use the \q{Username} field, but does not support
+passwords.
+
+\b You can specify a way to include a username and password in the
+Telnet proxy command (see \k{config-proxy-command}).
+
+\S{config-proxy-command} Specifying the Telnet proxy command
+
+\cfg{winhelp-topic}{proxy.command}
+
+If you are using the 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.
+
+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
+other character. \c{\\\\} is used to encode the \c{\\} character
+itself.
+
+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{%%}.
+
+If the 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
+
+This will send your username and password as the first two lines to
+the proxy, followed by a command to connect to the desired host and
+port. Note that if you do not include the \c{%user} or \c{%pass}
+tokens in the Telnet command, then the \q{Username} and \q{Password}
+configuration fields will be ignored.
+
+\S{config-proxy-socksver} Selecting the version of the SOCKS protocol
+
+\cfg{winhelp-topic}{proxy.socksver}
+
+SOCKS servers exist in two versions: version 5
+(\W{http://www.ietf.org/rfc/rfc1928.txt}{RFC 1928}) and the earlier
+version 4. The \q{SOCKS Version} radio buttons allow you to select
+which one to use, if you have selected the SOCKS proxy type.
+
\H{config-telnet} The Telnet panel
The Telnet panel allows you to configure options that only apply to
\S{config-termspeed} \q{Terminal-speed string}
+\cfg{winhelp-topic}{telnet.termspeed}
+
+Telnet allows the client to send a text string that describes the
+terminal speed. PuTTY lets you configure this, in case you find the
+server is reacting badly to the default value. (I'm not aware of any
+servers that do have a problem with it.)
+
\S{config-environ} Setting environment variables on the server
+\cfg{winhelp-topic}{telnet.environ}
+
+The Telnet protocol also provides a means for the client to pass
+environment variables to the server. Many Telnet servers have
+stopped supporting this feature due to security flaws, but PuTTY
+still supports it for the benefit of any servers which have found
+other ways around the security problems than just disabling the
+whole mechanism.
+
+To add an environment variable to the list transmitted down the
+connection, you enter the variable name in the \q{Variable} box,
+enter its value in the \q{Value} box, and press the \q{Add} button.
+To remove one from the list, select it in the list box and press
+\q{Remove}.
+
\S{config-oldenviron} \q{Handling of OLD_ENVIRON ambiguity}
+\cfg{winhelp-topic}{telnet.oldenviron}
+
+The original Telnet mechanism for passing 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
+implementations were already using.
+
+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
+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
+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
+
+\cfg{winhelp-topic}{telnet.passive}
+
+In a Telnet connection, there are two types of data passed between
+the client and the server: actual text, and \e{negotiations} about
+which Telnet extra features to use.
+
+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 \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
+passive mode to see if it helps.
+
+\S{config-telnetkey} \q{Keyboard sends telnet Backspace and Interrupt}
+
+\cfg{winhelp-topic}{telnet.specialkeys}
+
+If this box is checked, the Backspace key on the keyboard will send
+the Telnet special backspace code, and Control-C will send the
+Telnet special interrupt code. 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}
+
+\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
+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.
+
+Most Unix-style Telnet servers don't mind whether they receive
+Telnet New Line or Control-M; some servers do expect New Line, and
+some servers prefer to see ^M. If you are seeing surprising
+behaviour when you press Return in a Telnet session, you might try
+turning this option off to see if it helps.
+
+\H{config-rlogin} The Rlogin panel
+
+The Rlogin panel allows you to configure options that only apply to
+Rlogin sessions.
+
+\S{config-rlogin-termspeed} \q{Terminal-speed string}
+
+\cfg{winhelp-topic}{rlogin.termspeed}
+
+Like Telnet, Rlogin allows the client to send a text string that
+describes the terminal speed. PuTTY lets you configure this, in case
+you find the server is reacting badly to the default value. (I'm not
+aware of any servers that do have a problem with it.)
+
+\S{config-rlogin-localuser} \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
+\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.
+
+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
+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.
+
+Windows does not have this restriction: \e{any} user can initiate an
+outgoing connection from a low-numbered port. Hence, the Rlogin
+\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.
+
+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
+name).
+
\H{config-ssh} The SSH panel
The SSH panel allows you to configure options that only apply to
\S{config-command} Executing a specific command on the server
-\S{config-auth} SSH authentication options
+\cfg{winhelp-topic}{ssh.command}
+
+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}
+
+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.
+
+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-comp} \q{Enable compression}
+
+\cfg{winhelp-topic}{ssh.compress}
+
+This enables data compression in the SSH connection: data sent by
+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.
+
+\S{config-ssh-prot} \q{Preferred 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?}
+
+PuTTY will attempt to use protocol 1 if the server you connect to
+does not offer protocol 2, and vice versa.
+
+If you select \q{1 only} or \q{2 only} here, PuTTY will only connect
+if the server you connect to offers the SSH protocol version you
+have specified.
+
+\S{config-ssh-encryption} Encryption algorithm selection
+
+\cfg{winhelp-topic}{ssh.ciphers}
+
+PuTTY supports a variety of different encryption algorithms, 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
+you make an SSH connection, PuTTY will search down the list from the
+top until it finds an algorithm supported by the server, and then
+use that.
+
+If the algorithm PuTTY finds is below the \q{warn below here} line,
+you will see a warning box when you make the connection:
+
+\c The first cipher supported by the server
+\c is single-DES, which is below the configured
+\c warning threshold.
+\c Do you want to continue with this connection?
+
+This warns you that the first available encryption is not a very
+secure one. Typically you would put the \q{warn below here} line
+between the encryptions you consider secure and the ones you
+consider substandard. By default, PuTTY supplies a preference order
+intended to reflect a reasonable preference in terms of security and
+speed.
+
+In SSH-2, the encryption algorithm is negotiated independently for
+each direction of the connection, although PuTTY does not support
+separate configuration of the preference orders. As a result you may
+get two warnings similar to the one above, possibly with different
+encryptions.
+
+Single-DES is not supported natively in the SSH 2 draft protocol
+standards. One or two server implementations do support it, by a
+non-standard name. PuTTY can use single-DES to interoperate with
+these servers if you enable the \q{Enable non-standard single-DES in
+SSH 2} option; by default this is disabled and PuTTY will stick to
+the standard.
+
+\H{config-ssh-auth} The Auth panel
+
+The Auth panel allows you to configure authentication options for
+SSH sessions.
+
+\S{config-ssh-tis} \q{Attempt TIS or 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.
+
+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
+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}
+
+\cfg{winhelp-topic}{ssh.auth.ki}
+
+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.
+
+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}
+
+\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
+option will do nothing.
+
+See \k{pageant} for general information on Pageant, and
+\k{pageant-forward} for information on agent forwarding. Note that
+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}
+
+\cfg{winhelp-topic}{ssh.auth.changeuser}
+
+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
+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
+an error message.)
+
+For this reason, PuTTY will by default not prompt you for your
+username more than once, in case the server complains. If you know
+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}
+
+\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
+about public key authentication in SSH.
+
+This key must be in PuTTY's native format (\c{*.PPK}).
+
+\H{config-ssh-tunnels} The Tunnels panel
+
+The Tunnels panel allows you to configure tunnelling of other
+connection types through an SSH connection.
+
+\S{config-ssh-x11} X11 forwarding
+
+\cfg{winhelp-topic}{ssh.tunnels.x11}
+
+If your server lets you run X Window System applications, X11
+forwarding allows you to securely give those applications access to
+a local X display on your PC.
+
+To enable X11 forwarding, check the \q{Enable X11 forwarding} box.
+If your X display is not the primary display on your local machine
+(which it almost certainly will be unless you have deliberately
+arranged otherwise), you need to enter its location in the \q{X
+display location} box.
+
+See \k{using-x-forwarding} for more information about X11
+forwarding.
+
+\S2{config-ssh-x11auth} Remote X11 authentication
+
+\cfg{winhelp-topic}{ssh.tunnels.x11auth}
+
+If you are using X11 forwarding, the virtual X server created on the
+SSH server machine will be protected by authorisation data. This
+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:
+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
+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
+with the current time. So an eavesdropper who captures an
+\cw{XDM-AUTHORIZATION-1} string cannot immediately re-use it for
+their own X connection.
+
+PuTTY's support for \cw{XDM-AUTHORIZATION-1} is a somewhat
+experimental feature, and may encounter several problems:
+
+\b Some X clients probably do not even support
+\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
+a forwarded connection in a machine-readable format, so it's
+impossible to verify the \cw{XDM-AUTHORIZATION-1} data.
+
+\b You may find this feature causes problems with some SSH servers,
+which will not clean up \cw{XDM-AUTHORIZATION-1} data after a
+session, so that if you then connect to the same server using
+a client which only does \cw{MIT-MAGIC-COOKIE-1} and are allocated
+the same remote display number, you might find that out-of-date
+authentication data is still present on your server and your X
+connections fail.
+
+PuTTY's default is \cw{MIT-MAGIC-COOKIE-1}. If you change it, you
+should be sure you know what you're doing.
+
+\S{config-ssh-portfwd} Port forwarding
+
+\cfg{winhelp-topic}{ssh.tunnels.portfwd}
+
+Port forwarding allows you to tunnel other types of 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
+the port forwardings that PuTTY will try to set up when it connects
+to the server. By default no port forwardings are set up, so this
+list is empty.
+
+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}).
+
+\b Enter a source 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.
+
+\b Enter a hostname and port number separated by a colon, in the
+\q{Destination} box. Connections received on the source port will be
+directed to this destination. For example, to connect to a POP-3
+server, you might enter \c{popserver.example.com:110}.
+
+\b Click the \q{Add} button. Your forwarding details should appear
+in the list box.
+
+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. Typically a Windows machine can be asked to
+listen on any single IP address in the \cw{127.*.*.*} range, and all
+of these are loopback addresses available only to the local machine.
+So if you forward (for example) \c{127.0.0.5:79} to a remote
+machine's \cw{finger} port, then you should be able to run commands
+such as \c{finger fred@127.0.0.5}. This can be useful if the program
+connecting to the forwarded port doesn't allow you to change the
+port number it uses. This feature is available for local-to-remote
+forwarded ports; SSH1 is unable to support it for remote-to-local
+ports, while SSH2 can support it in theory but servers will not
+necessarily cooperate.
+
+\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:
+
+\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
+that machines other than your client PC can connect to the forwarded
+port.
+
+\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).
+
+\H{config-ssh-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
+them unless it knows about the bug and works around it.
+
+Since most servers announce their software version number at the
+beginning of the SSH connection, PuTTY will attempt to detect which
+bugs it can expect to see in the server and automatically enable
+workarounds. However, sometimes it will make mistakes; if the server
+has been deliberately configured to conceal its version number, or
+if the server is a version which PuTTY's bug database does not know
+about, then PuTTY will not know what bugs to expect.
+
+The Bugs panel allows you to manually configure the bugs PuTTY
+expects to see in the server. Each bug can be configured in three
+states:
+
+\b \q{Off}: PuTTY will assume the server does not have the bug.
+
+\b \q{On}: PuTTY will assume the server \e{does} have the bug.
+
+\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}
+
+\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}).
+
+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
+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}
+
+\cfg{winhelp-topic}{ssh.bugs.plainpw1}
+
+When talking to an SSH1 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
+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
+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
+attack.
+
+\S{config-ssh-bug-rsa1} \q{Chokes on SSH1 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
+normally automatically try RSA authentication before falling back to
+passwords, so these servers will crash when they see the RSA attempt.
+
+If this bug is detected, PuTTY will go straight to password
+authentication. If this bug is enabled when talking to a correct
+server, the session will succeed, but of course RSA authentication
+will be impossible.
+
+This is an SSH1-specific bug.
+
+\S{config-ssh-bug-hmac2} \q{Miscomputes SSH2 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
+dies unexpectedly at the beginning of the session, saying
+\q{Incorrect MAC received on packet}.
+
+If this bug is detected, PuTTY will compute its HMAC keys in the
+same way as the buggy server, so that communication will still be
+possible. If this bug is enabled when talking to a correct server,
+communication will fail.
+
+This is an SSH2-specific bug.
+
+\S{config-ssh-bug-derivekey2} \q{Miscomputes SSH2 encryption keys}
+
+\cfg{winhelp-topic}{ssh.bugs.derivekey2}
+
+Versions below 2.1.0 of the SSH server software from \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}.
+
+If this bug is detected, PuTTY will compute its encryption keys in
+the same way as the buggy server, so that communication will still
+be possible. If this bug is enabled when talking to a correct
+server, communication will fail.
+
+This is an SSH2-specific bug.
+
+\S{config-ssh-bug-sig} \q{Requires padding on SSH2 RSA signatures}
+
+\cfg{winhelp-topic}{ssh.bugs.rsapad2}
+
+Versions below 3.3 of OpenSSH require SSH2 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
+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.
+
+If this bug is detected, PuTTY will pad its signatures in the way
+OpenSSH expects. If this bug is enabled when talking to a correct
+server, it is likely that no damage will be done, since correct
+servers usually still accept padded signatures because they're used
+to talking to OpenSSH.
+
+This is an SSH2-specific bug.
+
+\S{config-ssh-bug-dhgex} \q{Chokes on Diffie-Hellman group exchange}
+
+\cfg{winhelp-topic}{ssh.bugs.dhgex2}
+
+We have anecdotal evidence that some SSH servers claim to be able to
+perform Diffie-Hellman group exchange, but fail to actually do so
+when PuTTY tries to. If your SSH2 sessions spontaneously close
+immediately after opening the PuTTY window, it might be worth
+enabling the workaround for this bug to see if it helps.
+
+We have no hard evidence that any specific version of specific
+server software reliably demonstrates this bug. Therefore, PuTTY
+will never \e{assume} a server has this bug; if you want the
+workaround, you need to enable it manually.
+
+This is an SSH2-specific bug.
+
+\H{config-file} 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.
+
+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
+contents of the Registry back into the file, and deletes the
+Registry entries. This can all be done using the Regedit command
+line options, so it's all automatic. Here is what you need in
+\c{PUTTY.BAT}:
+
+\c @ECHO OFF
+\c regedit /s putty.reg
+\c regedit /s puttyrnd.reg
+\c start /w putty.exe
+\c regedit /e puttynew.reg HKEY_CURRENT_USER\Software\SimonTatham\PuTTY
+\c copy puttynew.reg putty.reg
+\c del puttynew.reg
+\c regedit /s puttydel.reg
+
+This batch file needs two auxiliary files: \c{PUTTYRND.REG} which
+sets up an initial safe location for the \c{PUTTY.RND} random seed
+file, and \c{PUTTYDEL.REG} which destroys everything in the Registry
+once it's been successfully saved back to the file.
+
+Here is \c{PUTTYDEL.REG}:
+
+\c REGEDIT4
+\c
+\c [-HKEY_CURRENT_USER\Software\SimonTatham\PuTTY]
+
+Here is an example \c{PUTTYRND.REG} file:
+
+\c REGEDIT4
+\c
+\c [HKEY_CURRENT_USER\Software\SimonTatham\PuTTY]
+\c "RandSeedFile"="a:\putty.rnd"
-\S{config-protocol} SSH protocol options
+You should replace \c{a:\\putty.rnd} with the location where you
+want to store your random number data. If the aim is to carry around
+PuTTY and its settings on one floppy, you probably want to store it
+on the floppy.