X-Git-Url: https://git.distorted.org.uk/u/mdw/putty/blobdiff_plain/9712b085411713471837d605406f5ef7ffa408b6..df0870fc8ceb5a8fea66a4d0fe00e7db12317e33:/doc/faq.but diff --git a/doc/faq.but b/doc/faq.but index dc83e907..2068bee5 100644 --- a/doc/faq.but +++ b/doc/faq.but @@ -1,4 +1,4 @@ -\versionid $Id: faq.but,v 1.23 2002/03/24 14:08:13 jacob Exp $ +\versionid $Id: faq.but,v 1.47 2003/05/22 08:43:50 simon Exp $ \A{faq} PuTTY FAQ @@ -20,16 +20,14 @@ listed there, it's been implemented. If it's listed as a change made development snapshots, in which case testing will be very welcome. \b try the -\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist.html}{Wishlist +\W{http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/}{Wishlist page}, and see if you can find the feature there. If it's on there, -it probably \e{hasn't} been implemented. +and not in the \q{Recently fixed} section, it probably \e{hasn't} been +implemented. \S{faq-ssh2}{Question} Does PuTTY support SSH v2? Yes. SSH v2 support has been available in PuTTY since version 0.50. -However, currently the \e{default} SSH protocol is v1; to select SSH -v2 if your server supports both, go to the SSH panel and change the -\e{Preferred SSH protocol version} option. Public key authentication (both RSA and DSA) in SSH v2 is new in version 0.52. @@ -37,10 +35,9 @@ version 0.52. \S{faq-ssh2-keyfmt}{Question} Does PuTTY support reading OpenSSH or \cw{ssh.com} SSHv2 private key files? -Not at present. OpenSSH and \cw{ssh.com} have totally different -formats for private key files, and neither one is particularly -pleasant, so PuTTY has its own. We do plan to write a converter at -some stage. +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? @@ -163,46 +160,46 @@ happens. \H{faq-ports} Ports to other operating systems The eventual goal is for PuTTY to be a multi-platform program, able -to run on at least Windows, MacOS and Unix. Whether this will -actually ever happen I have no idea, but it is the plan. A Mac port -has been started, but is only half-finished and currently not moving -very fast. +to run on at least Windows, Mac OS and Unix. Porting will become easier once PuTTY has a generalised porting layer, drawing a clear line between platform-dependent and -platform-independent code. The general intention is for this porting -layer to evolve naturally as part of the process of doing the first -port. One particularly nasty part of this will be separating the -many configuration options into platform-dependent and -platform-independent ones; for example, the options controlling when -the Windows System menu appears will be pretty much meaningless -under X11 or perhaps other windowing systems, whereas Telnet Passive -Mode is universal and shouldn't need to be specified once for each -platform. +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. \S{faq-ports-general}{Question} What ports of PuTTY exist? -Currently, PuTTY only runs on full Win32 systems. This includes -Windows 95, 98, and ME, and it includes Windows NT, Windows 2000 and -Windows XP. +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. -It does \e{not} include Windows CE (see \k{faq-wince}), and it does -not quite include the Win32s environment under Windows 3.1 (see -\k{faq-win31}). +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 ports for any other systems at the present time. If -anyone told you we had a Unix port, or an iPaq port, or any other -port of PuTTY, they were mistaken. We don't. +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, +or any other port of PuTTY, they were mistaken. We don't. -\S{faq-wince}{Question} Will there be a port to Windows CE? +\S{faq-unix}{Question} Will there be 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, and also \c{pterm} - an +\cw{xterm}-type program which supports the same terminal emulation +as PuTTY. We do not yet have Unix ports of PSCP, PSFTP, Pageant or +PuTTYgen. -Probably not in the particularly near future. Despite sharing large -parts of the Windows API, in practice WinCE doesn't appear to be -significantly easier to port to than a totally different operating -system. +\S{faq-wince}{Question} Will there be a port to Windows CE or PocketPC? -However, PuTTY on portable devices would clearly be a useful thing, -so in the long term I hope there will be a WinCE port. +It's currently being worked on, but it's only in its early stages yet, +and certainly isn't yet useful. PuTTY on portable devices would +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? @@ -223,18 +220,9 @@ testing in this area would be very welcome! \S{faq-mac-port}{Question} Will there be a port to the Mac? -A Mac port was started once and is half-finished, but development -has been static for some time and the main PuTTY code has moved on, -so it's not clear how quickly development would resume even if -developer effort were available. - -\S{faq-unix}{Question} Will there be a port to Unix? - -I hope so, if only so that I can have an \cw{xterm}-like program -that supports exactly the same terminal emulation as PuTTY. If and -when we do do a Unix port, it will have a local-terminal back end so -it can be used like an \cw{xterm}, rather than only being usable as -a network utility. +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. \S{faq-epoc}{Question} Will there be a port to EPOC? @@ -243,6 +231,10 @@ even on systems the developers \e{do} already know how to program for, it might be a long time before any of us get round to learning a new system and doing the port for that. +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/} + \H{faq-embedding} Embedding PuTTY in other programs \S{faq-dll}{Question} Is the SSH or Telnet code available as a DLL? @@ -331,7 +323,10 @@ 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 @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.) \S{faq-startssh}{Question} How can I start an SSH session straight from the command line? @@ -366,10 +361,13 @@ 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, port forwarding, SSH v2, etc.) in PSCP, PSFTP and Plink? +keys, proxying, cipher selection, etc.) in PSCP, PSFTP and Plink? + +Most major features (e.g., public keys, port forwarding) are available +through command line options. See the documentation. -The command-line tools are currently rather short of command line -options to enable this sort of thing. However, you can use most of +Not all features are accessible from the command line yet, although +we'd like to fix this. In the meantime, you can use most of PuTTY's features if you create a PuTTY saved session, and then use the name of the saved session on the command line in place of a hostname. This works for PSCP, PSFTP and Plink (but don't expect @@ -507,7 +505,7 @@ 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 and the problem should go away. +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. @@ -532,6 +530,36 @@ and you should report it (although it might be a bug in your SSH server instead); but it doesn't necessarily mean you've actually run out of memory. +\S{faq-outofmem2}{Question} When attempting a file transfer, either +PSCP or PSFTP says \q{Out of memory} and dies. + +This is almost always caused by your 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. +This will usually lead to an \q{out of memory} error for much the +same reasons as given in \k{faq-outofmem}. + +This is a setup problem in your account on your server, \e{not} a +PSCP/PSFTP bug. Your login scripts should \e{never} generate output +during non-interactive sessions; secure file transfer is not the +only form of remote access that will break if they do. + +On Unix, a simple fix is to ensure that all the parts of your login +script that might generate output are in \c{.profile} (if you use a +Bourne shell derivative) or \c{.login} (if you use a C shell). +Putting them in more general files such as \c{.bashrc} or \c{.cshrc} +is liable to lead to problems. + +\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. + \S{faq-bce}{Question} When I run full-colour applications, I see areas of black space where colour ought to be. @@ -558,7 +586,7 @@ effect. It will only take effect once you reset the terminal. AltGr key. In PuTTY version 0.51, the AltGr key was broken. Upgrade to version -0.52. +0.52 or better. \S{faq-idleout}{Question} My PuTTY sessions unexpectedly close after they are idle for a while. @@ -683,17 +711,22 @@ You should still read the page} on the PuTTY website (also provided as \k{feedback} in the manual), and follow the guidelines contained in that. -\S{faq-broken-openssh31}{Question} Since my SSH server was upgraded to -OpenSSH 3.1p1, I can no longer connect with PuTTY. +\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. There is a known problem when OpenSSH has been built against an incorrect version of OpenSSL; the quick workaround is to configure PuTTY to use SSH protocol 2 and the Blowfish cipher. +For more details and OpenSSH patches, see +\W{http://bugzilla.mindrot.org/show_bug.cgi?id=138}{bug 138} in the +OpenSSH BTS. + This is not a PuTTY-specific problem; if you try to connect with -another client you'll likely have similar problems. +another client you'll likely have similar problems. (Although PuTTY's +default cipher differs from many other clients.) -Configurations known to be broken (and symptoms): +\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) @@ -705,9 +738,43 @@ packet") \b SSH 1 with 3DES -For more details and OpenSSH patches, see -\W{http://bugzilla.mindrot.org/show_bug.cgi?id=138}{bug 138} in the -OpenSSH BTS. +\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. + +\e{Other versions:} we occasionally get reports of the same symptom +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? + +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 +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 +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 +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 +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). + +A fix is to configure sessions to RH8 systems to use UTF-8 +translation - see \k{config-charset} in the documentation. (Note that +if you use \q{Change Settings}, changes may not take place immediately +- see \k{faq-resetterm}.) + +If you really want to change the character set used by the server, the +right place is \c{/etc/sysconfig/i18n}, but this shouldn't be +necessary. \H{faq-secure} Security questions @@ -751,6 +818,16 @@ all. For this reason we now believe PuTTY's DSA implementation is probably OK. However, if you have the choice, we still recommend you use RSA instead. +\S{faq-virtuallock}{Question} Couldn't Pageant use +\cw{VirtualLock()} to stop private keys being written to disk? + +Unfortunately not. The \cw{VirtualLock()} function in the Windows +API doesn't do a proper job: it may prevent small pieces of a +process's memory from being paged to disk while the process is +running, but it doesn't stop the process's memory as a whole from +being swapped completely out to disk when the process is long-term +inactive. And Pageant spends most of its time inactive. + \H{faq-admin} Administrative questions \S{faq-domain}{Question} Would you like me to register you a nicer @@ -811,13 +888,11 @@ general-subscription mailing list, what is? There isn't one, that we know of. -If someone else wants to set up a mailing list for PuTTY users to -help each other with common problems, that would be fine with us; -but the PuTTY team would almost certainly not have the time to read -it, so any questions the list couldn't answer would have to be -forwarded on to us by the questioner. In any case, it's probably -better to use the established newsgroup \cw{comp.security.ssh} for -this purpose. +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. \S{faq-donations}{Question} How can I donate to PuTTY development? @@ -848,6 +923,15 @@ developers. If you want to be sure your donation is going towards something worthwhile, ask us first. If you don't like these terms, feel perfectly free not to donate. We don't mind. +\H{faq-misc} Miscellaneous questions + +\S{faq-openssh}{Question} Is PuTTY a port of 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. + \S{faq-sillyputty}{Question} Where can I buy silly putty? You're looking at the wrong web site; the only PuTTY we know about @@ -858,8 +942,15 @@ PuTTY team can personally recommend Thinking Putty, which you can buy from Crazy Aaron's Putty World, at \W{http://www.puttyworld.com}\cw{www.puttyworld.com}. -\S{faq-pronounce}{Question} How do I pronounce PuTTY? +\S{faq-meaning}{Question} What does \q{PuTTY} mean? + +It's the name of a popular SSH and Telnet client. Any other meaning +is in the eye of the beholder. It's been rumoured that \q{PuTTY} +is the antonym of \q{\cw{getty}}, or that it's the stuff that makes your +Windows useful, or that it's a kind of plutonium Teletype. We +couldn't possibly comment on such allegations. + +\S{faq-pronounce}{Question} How do I pronounce \q{PuTTY}? -Exactly like the normal word \q{putty}. Just like the stuff you put -on window frames. (One of the reasons it's called PuTTY is because -it makes Windows usable. :-) +Exactly like the English word \q{putty}, which we pronounce +/\u02C8{'}p\u028C{V}t\u026A{I}/.