-\versionid $Id: faq.but,v 1.54 2004/02/04 18:39:14 jacob Exp $
+\define{versionidfaq} \versionid $Id$
-\A{faq} PuTTY FAQ
+\A{faq} PuTTY \i{FAQ}
This FAQ is published on the PuTTY web site, and also provided as an
appendix in the manual.
\H{faq-intro} Introduction
-\S{faq-what} What is PuTTY?
+\S{faq-what}{Question} What is PuTTY?
PuTTY is a client program for the SSH, Telnet and Rlogin network
protocols.
\H{faq-support} Features supported in PuTTY
-In general, if you want to know if PuTTY supports a particular
-feature, you should look for it on the
+\I{supported features}In general, if you want to know if PuTTY supports
+a particular feature, you should look for it on the
\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/}{PuTTY web site}.
In particular:
and not in the \q{Recently fixed} section, it probably \e{hasn't} been
implemented.
-\S{faq-ssh2}{Question} Does PuTTY support SSH v2?
+\S{faq-ssh2}{Question} Does PuTTY support SSH-2?
-Yes. SSH v2 support has been available in PuTTY since version 0.50.
+Yes. SSH-2 support has been available in PuTTY since version 0.50.
-Public key authentication (both RSA and DSA) in SSH v2 is new in
+Public key authentication (both RSA and DSA) in SSH-2 is new in
version 0.52.
\S{faq-ssh2-keyfmt}{Question} Does PuTTY support reading OpenSSH or
-\cw{ssh.com} SSHv2 private key files?
+\cw{ssh.com} SSH-2 private key files?
PuTTY doesn't support this natively, but as of 0.53
PuTTYgen can convert both OpenSSH and \cw{ssh.com} private key
files into PuTTY's format.
-\S{faq-ssh1}{Question} Does PuTTY support SSH v1?
+\S{faq-ssh1}{Question} Does PuTTY support SSH-1?
-Yes. SSH 1 support has always been available in PuTTY.
+Yes. SSH-1 support has always been available in PuTTY.
-\S{faq-localecho}{Question} Does PuTTY support local echo?
+\S{faq-localecho}{Question} Does PuTTY support \i{local echo}?
Yes. Version 0.52 has proper support for local echo.
the Terminal panel, in the section marked \q{Line discipline
options}.
+\S{faq-savedsettings}{Question} Does PuTTY support storing settings,
+so I don't have to change them every time?
+
+Yes, all of PuTTY's settings can be saved in named session profiles.
+You can also change the default settings that are used for new sessions.
+See \k{config-saving} in the documentation for how to do this.
+
\S{faq-disksettings}{Question} Does PuTTY support storing its
settings in a disk file?
Yes; this is a new feature in version 0.52.
\S{faq-password-remember}{Question} Does PuTTY have the ability to
-remember my password so I don't have to type it every time?
+\i{remember my password} so I don't have to type it every time?
No, it doesn't.
authentication.
\S{faq-hostkeys}{Question} Is there an option to turn off the
-annoying host key prompts?
+\I{verifying the host key}annoying host key prompts?
No, there isn't. And there won't be. Even if you write it yourself
and send us the patch, we won't accept it.
ones will not. Adding an option to turn host key checking off
completely is the wrong solution and we will not do it.
-If you have host keys available in the common \c{known_hosts} format,
+If you have host keys available in the common \i\c{known_hosts} format,
we have a script called
-\W{http://cvs.tartarus.org/putty/contrib/kh2reg.py}\c{kh2reg.py}
+\W{http://www.tartarus.org/~simon-anonsvn/viewcvs.cgi/putty/contrib/kh2reg.py?view=markup}\c{kh2reg.py}
to convert them to a Windows .REG file, which can be installed ahead of
time by double-clicking or using \c{REGEDIT}.
anyone else wants to try it.
\S{faq-pscp-ascii}{Question} Can PSCP or PSFTP transfer files in
-ASCII mode?
+\i{ASCII} mode?
Unfortunately not.
layer, drawing a clear line between platform-dependent and
platform-independent code. The general intention was for this
porting layer to evolve naturally as part of the process of doing
-the first port; a Unix port is now under way and the plan seems to
-be working so far.
+the first port; a Unix port has now been released and the plan
+seems to be working so far.
\S{faq-ports-general}{Question} What ports of PuTTY exist?
-Currently, release versions of PuTTY only run on full Win32 systems.
-This includes Windows 95, 98, and ME, and it includes Windows NT,
-Windows 2000 and Windows XP. In the development code, partial ports
-to Unix (see \k{faq-unix}) and the Mac OS (see \k{faq-mac-port}).
-are under way.
+Currently, release versions of PuTTY tools only run on full Win32
+systems and Unix. \q{Win32} includes Windows 95, 98, and ME, and it
+includes Windows NT, Windows 2000 and Windows XP.
+
+In the development code, a partial port to the Mac OS (see
+\k{faq-mac-port}) is under way.
Currently PuTTY does \e{not} run on Windows CE (see \k{faq-wince}),
and it does not quite run on the Win32s environment under Windows
3.1 (see \k{faq-win31}).
We do not have release-quality ports for any other systems at the
-present time. If anyone told you we had a Mac port, or an iPaq port,
+present time. If anyone told you we had an EPOC port, or an iPaq port,
or any other port of PuTTY, they were mistaken. We don't.
-\S{faq-unix}{Question} Will there be a port to Unix?
+There are some third-party ports to various platforms, mentioned
+on the Links page of our website.
+
+\S{faq-unix}{Question} \I{Unix version}Is there a port to Unix?
-It's currently being worked on. If you look at the nightly source
-snapshots, you should find a \c{unix} subdirectory, which should
-build you Unix ports of Plink, PuTTY itself, PuTTYgen, PSCP, PSFTP,
-and also \c{pterm} - an \cw{xterm}-type program which supports the
-same terminal emulation as PuTTY. We do not yet have a Unix port of
+As of 0.54, there are Unix ports of most of the traditional PuTTY
+tools, and also one entirely new application.
+
+If you look at the source release, you should find a \c{unix}
+subdirectory containing \c{Makefile.gtk}, which should build you Unix
+ports of Plink, PuTTY itself, PuTTYgen, PSCP, PSFTP, and also
+\i\c{pterm} - an \cw{xterm}-type program which supports the same
+terminal emulation as PuTTY. We do not yet have a Unix port of
Pageant.
+If you don't have \i{Gtk}, you should still be able to build the
+command-line tools.
+
+Note that Unix PuTTY has mostly only been tested on Linux so far;
+portability problems such as BSD-style ptys or different header file
+requirements are expected.
+
+\S{faq-unix-why}{Question} What's the point of the Unix port? Unix
+has OpenSSH.
+
+All sorts of little things. \c{pterm} is directly useful to anyone
+who prefers PuTTY's terminal emulation to \c{xterm}'s, which at
+least some people do. Unix Plink has apparently found a niche among
+people who find the complexity of OpenSSL makes OpenSSH hard to
+install (and who don't mind Plink not having as many features). Some
+users want to generate a large number of SSH keys on Unix and then
+copy them all into PuTTY, and the Unix PuTTYgen should allow them to
+automate that conversion process.
+
+There were development advantages as well; porting PuTTY to Unix was
+a valuable path-finding effort for other future ports, and also
+allowed us to use the excellent Linux tool
+\W{http://valgrind.kde.org/}{Valgrind} to help with debugging, which
+has already improved PuTTY's stability on \e{all} platforms.
+
+However, if you're a Unix user and you can see no reason to switch
+from OpenSSH to PuTTY/Plink, then you're probably right. We don't
+expect our Unix port to be the right thing for everybody.
+
\S{faq-wince}{Question} Will there be a port to Windows CE or PocketPC?
It's currently being worked on, but it's only in its early stages yet,
clearly be a useful thing, so in the long term I hope it can be
brought up to release quality.
-\S{faq-win31}{Question} Is there a port to Windows 3.1?
+There's also a third-party port at
+\W{http://pocketputty.duxy.net/}\c{http://pocketputty.duxy.net/}.
+
+\S{faq-win31}{Question} Is there a port to \i{Windows 3.1}?
PuTTY is a 32-bit application from the ground up, so it won't run on
Windows 3.1 as a native 16-bit program; and it would be \e{very}
allocation mechanisms.
However, it is possible in theory to compile the existing PuTTY
-source in such a way that it will run under Win32s (an extension to
+source in such a way that it will run under \i{Win32s} (an extension to
Windows 3.1 to let you run 32-bit programs). In order to do this
you'll need the right kind of C compiler - modern versions of Visual
C at least have stopped being backwards compatible to Win32s. Also,
If you're interested in running PuTTY under Windows 3.1, help and
testing in this area would be very welcome!
-\S{faq-mac-port}{Question} Will there be a port to the Mac?
+\S{faq-mac-port}{Question} Will there be a port to the \I{Mac OS}Mac?
+
+There are several answers to this question:
+
+\b The Unix/Gtk port is already fully working under Mac OS X as an X11
+application.
+
+\b A native (Cocoa) Mac OS X port is in progress. It's just about
+usable, but is of nowhere near release quality yet, and is likely to
+behave in unexpected ways.
-There is a port to the Mac OS in progress. It's just about usable, but
-has an awful lot of gaps and rough edges that will need cleaning up
-before release.
+\b A separate port to the classic Mac OS (pre-OSX) is also in
+progress; it too is not ready yet.
\S{faq-epoc}{Question} Will there be a port to EPOC?
However, some of the work has been done by other people, and a beta
port of PuTTY for the Nokia 9200 Communicator series is available
-from \W{http://www.s2.org/putty/}\cw{http://www.s2.org/putty/}
+from \W{http://s2putty.sourceforge.net/}\cw{http://s2putty.sourceforge.net/}
\H{faq-embedding} Embedding PuTTY in other programs
\H{faq-details} Details of PuTTY's operation
-\S{faq-term}{Question} What terminal type does PuTTY use?
+\S{faq-term}{Question} What \i{terminal type} does PuTTY use?
For most purposes, PuTTY can be considered to be an \cw{xterm}
terminal.
-PuTTY also supports some terminal control sequences not supported by
+PuTTY also supports some terminal \i{control sequences} not supported by
the real \cw{xterm}: notably the Linux console sequences that
reconfigure the colour palette, and the title bar control sequences
-used by \cw{DECterm} (which are different from the \cw{xterm} ones;
+used by \i\cw{DECterm} (which are different from the \cw{xterm} ones;
PuTTY supports both).
By default, PuTTY announces its terminal type to the server as
\S{faq-settings}{Question} Where does PuTTY store its data?
-PuTTY stores most of its data (saved sessions, SSH host keys) in the
-Registry. The precise location is
+On Windows, PuTTY stores most of its data (saved sessions, SSH host
+keys) in the \i{Registry}. The precise location is
\c HKEY_CURRENT_USER\Software\SimonTatham\PuTTY
PuTTY also requires a random number seed file, to improve the
unpredictability of randomly chosen data needed as part of the SSH
-cryptography. This is stored by default in your Windows home
-directory (\c{%HOMEDRIVE%\\%HOMEPATH%}), or in the actual Windows
-directory (such as \c{C:\\WINDOWS}) if the home directory doesn't
-exist, for example if you're using Win95. If you want to change the
-location of the random number seed file, you can put your chosen
-pathname in the Registry, at
+cryptography. This is stored by default in a file called \i\c{PUTTY.RND}
+in your Windows home directory (\c{%HOMEDRIVE%\\%HOMEPATH%}), or in
+the actual Windows directory (such as \c{C:\\WINDOWS}) if the home
+directory doesn't exist, for example if you're using Win95. If you
+want to change the location of the random number seed file, you can
+put your chosen pathname in the Registry, at
\c HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\RandSeedFile
+On Unix, PuTTY stores all of this data in a directory \cw{~/.putty}.
+
\H{faq-howto} HOWTO questions
-\S{faq-startmax}{Question} How can I make PuTTY start up maximised?
+\S{faq-commands}{Question} \I{commands on the server}What commands
+can I type into my PuTTY terminal window?
+
+This is not a question you should be asking \e{us}. You need to read
+the manuals, or ask the administrator, of \e{the computer you have
+connected to}.
+
+PuTTY does not process the commands you type into it. It's only a
+communications tool. It makes a connection to another computer; it
+passes the commands you type to that other computer; and it passes
+the other computer's responses back to you. Therefore, the precise
+range of commands you can use will not depend on PuTTY, but on what
+kind of computer you have connected to and what software is running
+on it. The PuTTY team cannot help you with that.
+
+(Think of PuTTY as being a bit like a telephone. If you phone
+somebody up and you don't know what language to speak to make them
+understand you, it isn't \e{the telephone company}'s job to find
+that out for you. We just provide the means for you to get in touch;
+making yourself understood is somebody else's problem.)
+
+If you are unsure of where to start looking for the administrator of
+your server, a good place to start might be to remember how you
+found out the host name in the PuTTY configuration. If you were
+given that host name by e-mail, for example, you could try asking
+the person who sent you that e-mail. If your company's IT department
+provided you with ready-made PuTTY saved sessions, then that IT
+department can probably also tell you something about what commands
+you can type during those sessions. But the PuTTY maintainer team
+does not administer any server you are likely to be connecting to,
+and cannot help you with questions of this type.
+
+\S{faq-startmax}{Question} How can I make PuTTY start up \i{maximise}d?
Create a Windows shortcut to start PuTTY from, and set it as \q{Run
Maximized}.
-\S{faq-startsess}{Question} How can I create a Windows shortcut to
+\S{faq-startsess}{Question} How can I create a \i{Windows shortcut} to
start a particular saved session directly?
To run a PuTTY session saved under the name \q{\cw{mysession}},
create a Windows shortcut that invokes PuTTY with a command line
like
-\c \path\name\to\putty.exe -load mysession
+\c \path\name\to\putty.exe -load "mysession"
(Note: prior to 0.53, the syntax was \c{@session}. This is now
deprecated and may be removed at some point.)
a saved session that specifies the SSH protocol, and start the saved
session as shown in \k{faq-startsess}.
-\S{faq-cutpaste}{Question} How do I copy and paste between PuTTY and
+\S{faq-cutpaste}{Question} How do I \i{copy and paste} between PuTTY and
other Windows applications?
Copy and paste works similarly to the X Window System. You use the
You can also paste by pressing Shift-Ins.
-\S{faq-tunnels}{Question} How do I use X forwarding and port
-forwarding? I can't find the Tunnels panel.
-
-This is a new feature in version 0.52. You should upgrade.
-
\S{faq-options}{Question} How do I use all PuTTY's features (public
keys, proxying, cipher selection, etc.) in PSCP, PSFTP and Plink?
To use PSCP properly, run it from a Command Prompt window. See
\k{pscp} in the documentation for more details.
-\S{faq-pscp-spaces}{Question} How do I use PSCP to copy a file whose
-name has spaces in?
+\S{faq-pscp-spaces}{Question} \I{spaces in filenames}How do I use
+PSCP to copy a file whose name has spaces in?
If PSCP is using the traditional SCP protocol, this is confusing. If
you're specifying a file at the local end, you just use one set of
received on packet}?
One possible cause of this that used to be common is a bug in old
-SSH 2 servers distributed by \cw{ssh.com}. (This is not the only
+SSH-2 servers distributed by \cw{ssh.com}. (This is not the only
possible cause; see \k{errors-crc} in the documentation.)
-Version 2.3.0 and below of their SSH 2 server
+Version 2.3.0 and below of their SSH-2 server
constructs Message Authentication Codes in the wrong way, and
expects the client to construct them in the same wrong way. PuTTY
constructs the MACs correctly by default, and hence these old
If you are using PuTTY version 0.51 or below, you can enable the
workaround by going to the SSH panel and ticking the box labelled
-\q{Imitate SSH 2 MAC bug}. It's possible that you might have to do
+\q{Imitate SSH2 MAC bug}. It's possible that you might have to do
this with 0.52 as well, if a buggy server exists that PuTTY doesn't
know about.
-In this context MAC stands for Message Authentication Code. It's a
+In this context MAC stands for \ii{Message Authentication Code}. It's a
cryptographic term, and it has nothing at all to do with Ethernet
MAC (Media Access Control) addresses.
that was part of the PSCP protocol exchange, and instead it saw data
that it couldn't make any sense of at all.
-This almost always happens because the startup scripts in your
+This almost always happens because the \i{startup scripts} in your
account on the server machine are generating output. This is
impossible for PSCP, or any other SCP client, to work around. You
should never use startup files (\c{.bashrc}, \c{.cshrc} and so on)
then all other SCP clients are likely to fail in exactly the same
way. The problem is at the server end.
-\S{faq-colours}{Question} I clicked on a colour in the Colours
+\S{faq-colours}{Question} I clicked on a colour in the \ii{Colours}
panel, and the colour didn't change in my terminal.
That isn't how you're supposed to use the Colours panel.
only allow you to adjust the \e{shade} of green used when PuTTY is
instructed by the server to display green text.
-\S{faq-winsock2}{Question} Plink on Windows 95 says it can't find
-\cw{WS2_32.DLL}.
+\S{faq-winsock2}{Question} Plink on \i{Windows 95} says it can't find
+\i\cw{WS2_32.DLL}.
Plink requires the extended Windows network library, WinSock version
2. This is installed as standard on Windows 98 and above, and on
the
\W{http://www.microsoft.com/windows95/downloads/contents/wuadmintools/s_wunetworkingtools/w95sockets2/}{WinSock 2 upgrade}:
-\c http://www.microsoft.com/windows95/downloads/contents/wuadmintools/
-\c s_wunetworkingtools/w95sockets2/
-
-\S{faq-rekey}{Question} My PuTTY sessions close after an hour and
-tell me \q{Server failed host key check}.
+\c http://www.microsoft.com/windows95/downloads/contents/
+\c wuadmintools/s_wunetworkingtools/w95sockets2/
-This is a bug in all versions of PuTTY up to and including 0.51. SSH
-v2 servers from \cw{ssh.com} will require the key exchange to be
-repeated one hour after the start of the connection, and PuTTY will
-get this wrong.
-
-Upgrade to version 0.52 or better and the problem should go away.
-
-\S{faq-outofmem}{Question} After trying to establish an SSH 2
-connection, PuTTY says \q{Out of memory} and dies.
+\S{faq-outofmem}{Question} After trying to establish an SSH-2
+connection, PuTTY says \q{\ii{Out of memory}} and dies.
If this happens just while the connection is starting up, this often
indicates that for some reason the client and server have failed to
out of memory.
\S{faq-outofmem2}{Question} When attempting a file transfer, either
-PSCP or PSFTP says \q{Out of memory} and dies.
+PSCP or PSFTP says \q{\ii{Out of memory}} and dies.
-This is almost always caused by your login scripts on the server
+This is almost always caused by your \i{login scripts} on the server
generating output. PSCP or PSFTP will receive that output when they
were expecting to see the start of a file transfer protocol, and
they will attempt to interpret the output as file-transfer protocol.
\S{faq-psftp-slow}{Question} PSFTP transfers files much slower than PSCP.
-We believe this is because the SFTP and SSH2 protocols are less
-efficient at bulk data transfer than SCP and SSH1, because every
-block of data transferred requires an acknowledgment from the far
-end. It would in theory be possible to queue several blocks of data
-to get round this speed problem, but as yet we haven't done the
-coding. If you really want this fixed, feel free to offer to help.
+The throughput of PSFTP 0.54 should be much better than 0.53b and
+prior; we've added code to the SFTP backend to queue several blocks
+of data rather than waiting for an acknowledgement for each. (The
+SCP backend did not suffer from this performance issue because SCP
+is a much simpler protocol.)
\S{faq-bce}{Question} When I run full-colour applications, I see
-areas of black space where colour ought to be.
+areas of black space where colour ought to be, or vice versa.
+
+You almost certainly need to change the \q{Use \i{background colour} to
+erase screen} setting in the Terminal panel. If there is too much
+black space (the commoner situation), you should enable it, while if
+there is too much colour, you should disable it. (See \k{config-erase}.)
-You almost certainly need to enable the \q{Use background colour to
-erase screen} setting in the Terminal panel. Note that if you do
-this in mid-session, it won't take effect until you reset the
-terminal (see \k{faq-resetterm}).
+In old versions of PuTTY, this was disabled by default, and would not
+take effect until you reset the terminal (see \k{faq-resetterm}).
+Since 0.54, it is enabled by default, and changes take effect
+immediately.
\S{faq-resetterm}{Question} When I change some terminal settings,
nothing happens.
-Some of the terminal options (notably Auto Wrap and
+Some of the terminal options (notably \ii{Auto Wrap} and
background-colour screen erase) actually represent the \e{default}
setting, rather than the currently active setting. The server can
send sequences that modify these options in mid-session, but when
the terminal is reset (by server action, or by you choosing \q{Reset
Terminal} from the System menu) the defaults are restored.
-If you want to change one of these options in the middle of a
-session, you will find that the change does not immediately take
-effect. It will only take effect once you reset the terminal.
+In versions 0.53b and prior, if you change one of these options in
+the middle of a session, you will find that the change does not
+immediately take effect. It will only take effect once you reset
+the terminal.
-\S{faq-altgr}{Question} I can't type characters that require the
-AltGr key.
-
-In PuTTY version 0.51, the AltGr key was broken. Upgrade to version
-0.52 or better.
+In version 0.54, the behaviour has changed - changes to these
+settings take effect immediately.
\S{faq-idleout}{Question} My PuTTY sessions unexpectedly close after
-they are idle for a while.
+they are \I{idle connections}idle for a while.
-Some types of firewall, and almost any router doing Network Address
-Translation (NAT, also known as IP masquerading), will forget about
+Some types of \i{firewall}, and almost any router doing Network Address
+Translation (\i{NAT}, also known as IP masquerading), will forget about
a connection through them if the connection does nothing for too
long. This will cause the connection to be rudely cut off when
contact is resumed.
this.
\S{faq-timeout}{Question} PuTTY's network connections time out too
-quickly when network connectivity is temporarily lost.
+quickly when \I{breaks in connectivity}network connectivity is
+temporarily lost.
This is a Windows problem, not a PuTTY problem. The timeout value
can't be set on per application or per session basis. To increase
the TCP timeout globally, you need to tinker with the Registry.
-On Windows 95, 98 or ME, the registry key you need to change is
+On Windows 95, 98 or ME, the registry key you need to create or
+change is
\c HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\
\c MSTCP\MaxDataRetries
(it must be of type DWORD in Win95, or String in Win98/ME).
+(See MS Knowledge Base article
+\W{http://support.microsoft.com/default.aspx?scid=kb;en-us;158474}{158474}
+for more information.)
-On Windows NT or 2000, the registry key is
+On Windows NT, 2000, or XP, the registry key to create or change is
\c HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\
\c Parameters\TcpMaxDataRetransmissions
and it must be of type DWORD.
+(See MS Knowledge Base articles
+\W{http://support.microsoft.com/default.aspx?scid=kb;en-us;120642}{120642}
+and
+\W{http://support.microsoft.com/default.aspx?scid=kb;en-us;314053}{314053}
+for more information.)
Set the key's value to something like 10. This will cause Windows to
try harder to keep connections alive instead of abandoning them.
\S{faq-puttyputty}{Question} When I \cw{cat} a binary file, I get
-`PuTTYPuTTYPuTTY' on my command line.
+\q{PuTTYPuTTYPuTTY} on my command line.
Don't do that, then.
your terminal is likely to cause various other unpleasant behaviour,
so this is only a small remedy.
-\S{faq-wintitle}{Question} When I \cw{cat} a binary file, my window
-title changes to a nonsense string.
+\S{faq-wintitle}{Question} When I \cw{cat} a binary file, my \i{window
+title} changes to a nonsense string.
Don't do that, then.
manual), and follow the guidelines contained in that.
\S{faq-openssh-bad-openssl}{Question} Since my SSH server was upgraded
-to OpenSSH 3.1p1/3.4p1, I can no longer connect with PuTTY.
+to \i{OpenSSH} 3.1p1/3.4p1, I can no longer connect with PuTTY.
There is a known problem when OpenSSH has been built against an
incorrect version of OpenSSL; the quick workaround is to configure
\e{OpenSSH 3.1p1:} configurations known to be broken (and symptoms):
-\b SSH 2 with AES cipher (PuTTY says "Assertion failed! Expression:
-(len & 15) == 0" in sshaes.c, or "Out of memory", or crashes)
+\b SSH-2 with AES cipher (PuTTY says \q{Assertion failed! Expression:
+(len & 15) == 0} in \cw{sshaes.c}, or \q{Out of memory}, or crashes)
-\b SSH 2 with 3DES (PuTTY says "Incorrect MAC received on packet")
+\b SSH-2 with 3DES (PuTTY says \q{Incorrect MAC received on packet})
-\b SSH 1 with Blowfish (PuTTY says "Incorrect CRC received on
-packet")
+\b SSH-1 with Blowfish (PuTTY says \q{Incorrect CRC received on
+packet})
-\b SSH 1 with 3DES
+\b SSH-1 with 3DES
-\e{OpenSSH 3.4p1:} as of 3.4p1, only the problem with SSH 1 and
+\e{OpenSSH 3.4p1:} as of 3.4p1, only the problem with SSH-1 and
Blowfish remains. Rebuild your server, apply the patch linked to from
bug 138 above, or use another cipher (e.g., 3DES) instead.
and workarounds with older versions of OpenSSH, although it's not
clear the underlying cause is the same.
-\S{faq-ssh2key-ssh1conn}{Question} Why do I see "Couldn't load private
-key from ..."? Why can PuTTYgen load my key but not PuTTY?
+\S{faq-ssh2key-ssh1conn}{Question} Why do I see \q{Couldn't load
+private key from ...}? Why can PuTTYgen load my key but not PuTTY?
It's likely that you've generated an SSH protocol 2 key with PuTTYgen,
-but you're trying to use it in an SSH 1 connection. SSH1 and SSH2 keys
+but you're trying to use it in an SSH-1 connection. SSH-1 and SSH-2 keys
have different formats, and (at least in 0.52) PuTTY's reporting of a
key in the wrong format isn't optimal.
-To connect using SSH 2 to a server that supports both versions, you
+To connect using SSH-2 to a server that supports both versions, you
need to change the configuration from the default (see \k{faq-ssh2}).
-\S{faq-rh8-utf8}{Question} When I'm connected to a Red Hat Linux 8.0
+\S{faq-rh8-utf8}{Question} When I'm connected to a \i{Red Hat Linux} 8.0
system, some characters don't display properly.
A common complaint is that hyphens in man pages show up as a-acute.
-With release 8.0, Red Hat appear to have made UTF-8 the default
+With release 8.0, Red Hat appear to have made \i{UTF-8} the default
character set. There appears to be no way for terminal emulators such
as PuTTY to know this (as far as we know, the appropriate escape
sequence to switch into UTF-8 mode isn't sent).
right place is \c{/etc/sysconfig/i18n}, but this shouldn't be
necessary.
+\S{faq-screen}{Question} Since I upgraded to PuTTY 0.54, the
+scrollback has stopped working when I run \c{screen}.
+
+PuTTY's terminal emulator has always had the policy that when the
+\q{\i{alternate screen}} is in use, nothing is added to the scrollback.
+This is because the usual sorts of programs which use the alternate
+screen are things like text editors, which tend to scroll back and
+forth in the same document a lot; so (a) they would fill up the
+scrollback with a large amount of unhelpfully disordered text, and
+(b) they contain their \e{own} method for the user to scroll back to
+the bit they were interested in. We have generally found this policy
+to do the Right Thing in almost all situations.
+
+Unfortunately, \c{screen} is one exception: it uses the alternate
+screen, but it's still usually helpful to have PuTTY's scrollback
+continue working. The simplest solution is to go to the Features
+control panel and tick \q{Disable switching to alternate terminal
+screen}. (See \k{config-features-altscreen} for more details.)
+Alternatively, you can tell \c{screen} itself not to use the
+alternate screen: the
+\W{http://www4.informatik.uni-erlangen.de/~jnweiger/screen-faq.html}{\c{screen}
+FAQ} suggests adding the line \cq{termcapinfo xterm ti@:te@} to your
+\cw{.screenrc} file.
+
+The reason why this only started to be a problem in 0.54 is because
+\c{screen} typically uses an unusual control sequence to switch to
+the alternate screen, and previous versions of PuTTY did not support
+this sequence.
+
+\S{faq-alternate-localhost}{Question} Since I upgraded \i{Windows XP}
+to Service Pack 2, I can't use addresses like \cw{127.0.0.2}.
+
+Some people who ask PuTTY to listen on \i{localhost} addresses other
+than \cw{127.0.0.1} to forward services such as \i{SMB} and \i{Windows
+Terminal Services} have found that doing so no longer works since
+they upgraded to WinXP SP2.
+
+This is apparently an issue with SP2 that is acknowledged by Microsoft
+in MS Knowledge Base article
+\W{http://support.microsoft.com/default.aspx?scid=kb;en-us;884020}{884020}.
+The article links to a fix you can download.
+
+(\e{However}, we've been told that SP2 \e{also} fixes the bug that
+means you need to use non-\cw{127.0.0.1} addresses to forward
+Terminal Services in the first place.)
+
+\S{faq-missing-slash}{Question} PSFTP commands seem to be missing a
+directory separator (slash).
+
+Some people have reported the following incorrect behaviour with
+PSFTP:
+
+\c psftp> pwd
+\e iii
+\c Remote directory is /dir1/dir2
+\c psftp> get filename.ext
+\e iiiiiiiiiiiiiiii
+\c /dir1/dir2filename.ext: no such file or directory
+
+This is not a bug in PSFTP. There is a known bug in some versions of
+portable \i{OpenSSH}
+(\W{http://bugzilla.mindrot.org/show_bug.cgi?id=697}{bug 697}) that
+causes these symptoms; it appears to have been introduced around
+3.7.x. It manifests only on certain platforms (AIX is what has been
+reported to us).
+
+There is a patch for OpenSSH attached to that bug; it's also fixed in
+recent versions of portable OpenSSH (from around 3.8).
+
+\S{faq-connaborted}{Question} Do you want to hear about \q{Software
+caused connection abort}?
+
+In the documentation for PuTTY 0.53 and 0.53b, we mentioned that we'd
+like to hear about any occurrences of this error. Since the release
+of PuTTY 0.54, however, we've been convinced that this error doesn't
+indicate that PuTTY's doing anything wrong, and we don't need to hear
+about further occurrences. See \k{errors-connaborted} for our current
+documentation of this error.
+
+\S{faq-rekey}{Question} My SSH-2 session \I{locking up, SSH-2
+sessions}locks up for a few seconds every so often.
+
+Recent versions of PuTTY automatically initiate \i{repeat key
+exchange} once per hour, to improve session security. If your client
+or server machine is slow, you may experience this as a delay of
+anything up to thirty seconds or so.
+
+These \I{delays, in SSH-2 sessions}delays are inconvenient, but they
+are there for your protection. If they really cause you a problem,
+you can choose to turn off periodic rekeying using the \q{Kex}
+configuration panel (see \k{config-ssh-kex}), but be aware that you
+will be sacrificing security for this. (Falling back to SSH-1 would
+also remove the delays, but would lose a \e{lot} more security
+still. We do not recommend it.)
+
+\S{faq-xpwontrun}{Question} PuTTY fails to start up. Windows claims that
+\q{the application configuration is incorrect}.
+
+This is caused by a bug in certain versions of \i{Windows XP} which is
+triggered by PuTTY 0.58. It can be avoided by installing
+Service Pack 2, by using a different version of PuTTY, or by installing
+a special \i{manifest file} alongside the PuTTY executable.
+The
+\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/xp-wont-run}{\q{xp-wont-run}}
+entry in PuTTY's wishlist has more details.
+
\H{faq-secure} Security questions
\S{faq-publicpc}{Question} Is it safe for me to download PuTTY and
floppy).
\S{faq-cleanup}{Question} What does PuTTY leave on a system? How can
-I clean up after it?
+I \i{clean up} after it?
PuTTY will leave some Registry entries, and a random seed file, on
the PC (see \k{faq-settings}). If you are using PuTTY on a public
PC, or somebody else's PC, you might want to clean these up when you
leave. You can do that automatically, by running the command
-\c{putty -cleanup}.
+\c{putty -cleanup}. (Note that this only removes settings for
+the currently logged-in user on \i{multi-user systems}.)
-\S{faq-dsa}{Question} How come PuTTY now supports DSA, when the
+If PuTTY was installed from the installer package, it will also
+appear in \q{Add/Remove Programs}. Older versions of the uninstaller
+do not remove the above-mentioned registry entries and file.
+
+\S{faq-dsa}{Question} How come PuTTY now supports \i{DSA}, when the
website used to say how insecure it was?
DSA has a major weakness \e{if badly implemented}: it relies on a
We already have some, thanks.
+\S{faq-link}{Question} Would you link to my web site from the PuTTY
+web site?
+
+Only if the content of your web page is of definite direct interest
+to PuTTY users. If your content is unrelated, or only tangentially
+related, to PuTTY, then the link would simply be advertising for
+you.
+
+One very nice effect of the Google ranking mechanism is that by and
+large, the most popular web sites get the highest rankings. This
+means that when an ordinary person does a search, the top item in
+the search is very likely to be a high-quality site or the site they
+actually wanted, rather than the site which paid the most money for
+its ranking.
+
+The PuTTY web site is held in high esteem by Google, for precisely
+this reason: lots of people have linked to it simply because they
+like PuTTY, without us ever having to ask anyone to link to us. We
+feel that it would be an abuse of this esteem to use it to boost the
+ranking of random advertisers' web sites. If you want your web site
+to have a high Google ranking, we'd prefer that you achieve this the
+way we did - by being good enough at what you do that people will
+link to you simply because they like you.
+
+In particular, we aren't interested in trading links for money (see
+above), and we \e{certainly} aren't interested in trading links for
+other links (since we have no advertising on our web site, our
+Google ranking is not even directly worth anything to us). If we
+don't want to link to you for free, then we probably won't want to
+link to you at all.
+
+If you have software based on PuTTY, or specifically designed to
+interoperate with PuTTY, or in some other way of genuine interest to
+PuTTY users, then we will probably be happy to add a link to you on
+our Links page. And if you're running a mirror of the PuTTY web
+site, we're \e{definitely} interested.
+
\S{faq-sourceforge}{Question} Why don't you move PuTTY to
SourceForge?
Also, security reasons. PuTTY is a security product, and as such it
is particularly important to guard the code and the web site against
unauthorised modifications which might introduce subtle security
-flaws. Therefore, we prefer that the CVS repository, web site and
+flaws. Therefore, we prefer that the Subversion repository, web site and
FTP site remain where they are, under the direct control of system
administrators we know and trust personally, rather than being run
by a large organisation full of people we've never met and which is
If someone else wants to set up a mailing list or other forum for
PuTTY users to help each other with common problems, that would be
fine with us, though the PuTTY team would almost certainly not have the
-time to read it. It's probably better to use the established
-newsgroup \cw{comp.security.ssh} for this purpose.
+time to read it. It's probably better to use one of the established
+newsgroups for this purpose (see \k{feedback-other-fora}).
\S{faq-donations}{Question} How can I donate to PuTTY development?
Having said all that, if you still really \e{want} to give us money,
we won't argue :-) The easiest way for us to accept donations is if
-you go to \W{http://www.e-gold.com}\cw{www.e-gold.com}, and deposit
-your donation in account number 174769. Then send us e-mail to let
-us know you've done so (otherwise we might not notice for months!).
-Alternatively, if e-gold isn't convenient for you, you can donate to
-\cw{<anakin@pobox.com>} using PayPal
-(\W{http://www.paypal.com/}\cw{www.paypal.com}).
+you send money to \cw{<anakin@pobox.com>} using PayPal
+(\W{http://www.paypal.com/}\cw{www.paypal.com}). Alternatively, if
+you don't trust PayPal, you could donate through e-gold
+(\W{http://www.e-gold.com}\cw{www.e-gold.com}): deposit your
+donation in account number 174769, then send us e-mail to let us
+know you've done so (otherwise we might not notice for months!).
Small donations (tens of dollars or tens of euros) will probably be
spent on beer or curry, which helps motivate our volunteer team to
something worthwhile, ask us first. If you don't like these terms,
feel perfectly free not to donate. We don't mind.
+\S{faq-permission}{Question} Can I have permission to put PuTTY on a
+cover disk / distribute it with other software / etc?
+
+Yes. You need not bother asking us explicitly for permission. You
+already have permission. Redistribution of the unmodified PuTTY
+binary in this way is entirely permitted by our licence (see
+\k{licence}), and you are welcome to do it as much as you like.
+
+If you are distributing PuTTY within your own organisation, or for
+use with your own product, then we recommend (but do not insist)
+that you offer your own first-line technical support, to answer
+questions directly relating to the interaction of PuTTY with your
+particular environment. If your users mail us directly, we won't be
+able to give them very much help about things specific to your own
+setup.
+
\H{faq-misc} Miscellaneous questions
-\S{faq-openssh}{Question} Is PuTTY a port of OpenSSH, or based on
+\S{faq-openssh}{Question} Is PuTTY a port of \i{OpenSSH}, or based on
OpenSSH?
No, it isn't. PuTTY is almost completely composed of code written
from scratch for PuTTY. The only code we share with OpenSSH is the
-detector for SSH1 CRC compensation attacks, written by CORE SDI S.A.
+detector for SSH-1 CRC compensation attacks, written by CORE SDI S.A.
\S{faq-sillyputty}{Question} Where can I buy silly putty?
\S{faq-pronounce}{Question} How do I pronounce \q{PuTTY}?
Exactly like the English word \q{putty}, which we pronounce
-/\u02C8{'}p\u028C{V}t\u026A{I}/.
+/\u02C8{'}p\u028C{V}ti/.
projects / u / mdw / putty / blobdiff