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1 | \define{versionidfaq} \versionid $Id$ |
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2 | |
421406a4 |
3 | \A{faq} PuTTY \i{FAQ} |
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4 | |
5 | This FAQ is published on the PuTTY web site, and also provided as an |
6 | appendix in the manual. |
7 | |
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8 | \H{faq-intro} Introduction |
9 | |
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10 | \S{faq-what}{Question} What is PuTTY? |
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11 | |
12 | PuTTY is a client program for the SSH, Telnet and Rlogin network |
13 | protocols. |
14 | |
15 | These protocols are all used to run a remote session on a computer, |
16 | over a network. PuTTY implements the client end of that session: the |
17 | end at which the session is displayed, rather than the end at which |
18 | it runs. |
19 | |
20 | In really simple terms: you run PuTTY on a Windows machine, and tell |
21 | it to connect to (for example) a Unix machine. PuTTY opens a window. |
22 | Then, anything you type into that window is sent straight to the |
23 | Unix machine, and everything the Unix machine sends back is |
24 | displayed in the window. So you can work on the Unix machine as if |
25 | you were sitting at its console, while actually sitting somewhere |
26 | else. |
27 | |
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28 | \H{faq-support} Features supported in PuTTY |
29 | |
421406a4 |
30 | \I{supported features}In general, if you want to know if PuTTY supports |
31 | a particular feature, you should look for it on the |
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32 | \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/}{PuTTY web site}. |
33 | In particular: |
34 | |
35 | \b try the |
36 | \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/changes.html}{changes |
37 | page}, and see if you can find the feature on there. If a feature is |
38 | listed there, it's been implemented. If it's listed as a change made |
39 | \e{since} the latest version, it should be available in the |
40 | development snapshots, in which case testing will be very welcome. |
41 | |
42 | \b try the |
ebe9a956 |
43 | \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/}{Wishlist |
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44 | page}, and see if you can find the feature there. If it's on there, |
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45 | and not in the \q{Recently fixed} section, it probably \e{hasn't} been |
46 | implemented. |
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47 | |
2e85c969 |
48 | \S{faq-ssh2}{Question} Does PuTTY support SSH-2? |
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49 | |
2e85c969 |
50 | Yes. SSH-2 support has been available in PuTTY since version 0.50. |
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51 | |
2e85c969 |
52 | Public key authentication (both RSA and DSA) in SSH-2 is new in |
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53 | version 0.52. |
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54 | |
a1d2976b |
55 | \S{faq-ssh2-keyfmt}{Question} Does PuTTY support reading OpenSSH or |
2e85c969 |
56 | \cw{ssh.com} SSH-2 private key files? |
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57 | |
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58 | PuTTY doesn't support this natively (see |
59 | \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/key-formats-natively.html}{the wishlist entry} |
60 | for reasons why not), but as of 0.53 |
a58b605b |
61 | PuTTYgen can convert both OpenSSH and \cw{ssh.com} private key |
62 | files into PuTTY's format. |
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63 | |
2e85c969 |
64 | \S{faq-ssh1}{Question} Does PuTTY support SSH-1? |
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65 | |
2e85c969 |
66 | Yes. SSH-1 support has always been available in PuTTY. |
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67 | |
421406a4 |
68 | \S{faq-localecho}{Question} Does PuTTY support \i{local echo}? |
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69 | |
32c37ecd |
70 | Yes. Version 0.52 has proper support for local echo. |
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71 | |
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72 | In version 0.51 and before, local echo could not be separated from |
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73 | local line editing (where you type a line of text locally, and it is |
74 | not sent to the server until you press Return, so you have the |
75 | chance to edit it and correct mistakes \e{before} the server sees |
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76 | it). New in version 0.52, local echo and local line editing are |
77 | separate options, and by default PuTTY will try to determine |
78 | automatically whether to enable them or not, based on which protocol |
79 | you have selected and also based on hints from the server. If you |
80 | have a problem with PuTTY's default choice, you can force each |
81 | option to be enabled or disabled as you choose. The controls are in |
82 | the Terminal panel, in the section marked \q{Line discipline |
83 | options}. |
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84 | |
270bd741 |
85 | \S{faq-savedsettings}{Question} Does PuTTY support storing settings, |
86 | so I don't have to change them every time? |
87 | |
88 | Yes, all of PuTTY's settings can be saved in named session profiles. |
00c1d39a |
89 | You can also change the default settings that are used for new sessions. |
270bd741 |
90 | See \k{config-saving} in the documentation for how to do this. |
91 | |
a1d2976b |
92 | \S{faq-disksettings}{Question} Does PuTTY support storing its |
70706890 |
93 | settings in a disk file? |
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94 | |
95 | Not at present, although \k{config-file} in the documentation gives |
96 | a method of achieving the same effect. |
97 | |
a1d2976b |
98 | \S{faq-fullscreen}{Question} Does PuTTY support full-screen mode, |
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99 | like a DOS box? |
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100 | |
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101 | Yes; this is a new feature in version 0.52. |
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102 | |
babac7bd |
103 | \S{faq-password-remember}{Question} Does PuTTY have the ability to |
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104 | \i{remember my password} so I don't have to type it every time? |
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105 | |
106 | No, it doesn't. |
107 | |
108 | Remembering your password is a bad plan for obvious security |
109 | reasons: anyone who gains access to your machine while you're away |
110 | from your desk can find out the remembered password, and use it, |
111 | abuse it or change it. |
112 | |
113 | In addition, it's not even \e{possible} for PuTTY to automatically |
114 | send your password in a Telnet session, because Telnet doesn't give |
115 | the client software any indication of which part of the login |
116 | process is the password prompt. PuTTY would have to guess, by |
117 | looking for words like \q{password} in the session data; and if your |
118 | login program is written in something other than English, this won't |
119 | work. |
120 | |
121 | In SSH, remembering your password would be possible in theory, but |
122 | there doesn't seem to be much point since SSH supports public key |
123 | authentication, which is more flexible and more secure. See |
124 | \k{pubkey} in the documentation for a full discussion of public key |
125 | authentication. |
126 | |
a1d2976b |
127 | \S{faq-hostkeys}{Question} Is there an option to turn off the |
421406a4 |
128 | \I{verifying the host key}annoying host key prompts? |
cad566a9 |
129 | |
130 | No, there isn't. And there won't be. Even if you write it yourself |
131 | and send us the patch, we won't accept it. |
132 | |
133 | Those annoying host key prompts are the \e{whole point} of SSH. |
134 | Without them, all the cryptographic technology SSH uses to secure |
135 | your session is doing nothing more than making an attacker's job |
136 | slightly harder; instead of sitting between you and the server with |
137 | a packet sniffer, the attacker must actually subvert a router and |
138 | start modifying the packets going back and forth. But that's not all |
139 | that much harder than just sniffing; and without host key checking, |
140 | it will go completely undetected by client or server. |
141 | |
142 | Host key checking is your guarantee that the encryption you put on |
143 | your data at the client end is the \e{same} encryption taken off the |
144 | data at the server end; it's your guarantee that it hasn't been |
145 | removed and replaced somewhere on the way. Host key checking makes |
146 | the attacker's job \e{astronomically} hard, compared to packet |
147 | sniffing, and even compared to subverting a router. Instead of |
148 | applying a little intelligence and keeping an eye on Bugtraq, the |
149 | attacker must now perform a brute-force attack against at least one |
150 | military-strength cipher. That insignificant host key prompt really |
151 | does make \e{that} much difference. |
152 | |
153 | If you're having a specific problem with host key checking - perhaps |
154 | you want an automated batch job to make use of PSCP or Plink, and |
155 | the interactive host key prompt is hanging the batch process - then |
156 | the right way to fix it is to add the correct host key to the |
157 | Registry in advance. That way, you retain the \e{important} feature |
158 | of host key checking: the right key will be accepted and the wrong |
159 | ones will not. Adding an option to turn host key checking off |
160 | completely is the wrong solution and we will not do it. |
161 | |
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162 | If you have host keys available in the common \i\c{known_hosts} format, |
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163 | we have a script called |
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164 | \W{http://svn.tartarus.org/sgt/putty/contrib/kh2reg.py?view=markup}\c{kh2reg.py} |
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165 | to convert them to a Windows .REG file, which can be installed ahead of |
166 | time by double-clicking or using \c{REGEDIT}. |
167 | |
a1d2976b |
168 | \S{faq-server}{Question} Will you write an SSH server for the PuTTY |
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169 | suite, to go with the client? |
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170 | |
171 | No. The only reason we might want to would be if we could easily |
172 | re-use existing code and significantly cut down the effort. We don't |
173 | believe this is the case; there just isn't enough common ground |
174 | between an SSH client and server to make it worthwhile. |
175 | |
176 | If someone else wants to use bits of PuTTY in the process of writing |
177 | a Windows SSH server, they'd be perfectly welcome to of course, but |
178 | I really can't see it being a lot less effort for us to do that than |
179 | it would be for us to write a server from the ground up. We don't |
180 | have time, and we don't have motivation. The code is available if |
181 | anyone else wants to try it. |
182 | |
67325335 |
183 | \S{faq-pscp-ascii}{Question} Can PSCP or PSFTP transfer files in |
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184 | \i{ASCII} mode? |
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185 | |
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186 | Unfortunately not. |
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187 | |
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188 | Until recently, this was a limitation of the file transfer protocols: |
189 | the SCP and SFTP protocols had no notion of transferring a file in |
190 | anything other than binary mode. (This is still true of SCP.) |
191 | |
192 | The current draft protocol spec of SFTP proposes a means of |
193 | implementing ASCII transfer. At some point PSCP/PSFTP may implement |
194 | this proposal. |
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195 | |
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196 | \H{faq-ports} Ports to other operating systems |
197 | |
198 | The eventual goal is for PuTTY to be a multi-platform program, able |
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199 | to run on at least Windows, Mac OS and Unix. |
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200 | |
201 | Porting will become easier once PuTTY has a generalised porting |
202 | layer, drawing a clear line between platform-dependent and |
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203 | platform-independent code. The general intention was for this |
204 | porting layer to evolve naturally as part of the process of doing |
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205 | the first port; a Unix port has now been released and the plan |
206 | seems to be working so far. |
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207 | |
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208 | \S{faq-ports-general}{Question} What ports of PuTTY exist? |
209 | |
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210 | Currently, release versions of PuTTY tools only run on full Win32 |
211 | systems and Unix. \q{Win32} includes Windows 95, 98, and ME, and it |
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212 | includes Windows NT, 2000, XP, and Vista. |
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213 | |
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214 | In the development code, partial ports to the Mac OSes exist (see |
215 | \k{faq-mac-port}). |
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216 | |
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217 | Currently PuTTY does \e{not} run on Windows CE (see \k{faq-wince}), |
218 | and it does not quite run on the Win32s environment under Windows |
219 | 3.1 (see \k{faq-win31}). |
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220 | |
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221 | We do not have release-quality ports for any other systems at the |
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222 | present time. If anyone told you we had an EPOC port, or an iPaq port, |
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223 | or any other port of PuTTY, they were mistaken. We don't. |
224 | |
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225 | There are some third-party ports to various platforms, mentioned |
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226 | on the |
227 | \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/links.html}{Links page of our website}. |
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228 | |
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229 | \S{faq-unix}{Question} \I{Unix version}Is there a port to Unix? |
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230 | |
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231 | As of 0.54, there are Unix ports of most of the traditional PuTTY |
232 | tools, and also one entirely new application. |
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233 | |
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234 | If you look at the source release, you should find a \c{unix} |
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235 | subdirectory. There are a couple of ways of building it, |
236 | including the usual \c{configure}/\c{make}; see the file \c{README} |
237 | in the source distribution. This should build you Unix |
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238 | ports of Plink, PuTTY itself, PuTTYgen, PSCP, PSFTP, and also |
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239 | \i\c{pterm} - an \cw{xterm}-type program which supports the same |
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240 | terminal emulation as PuTTY. We do not yet have a Unix port of |
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241 | Pageant. |
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242 | |
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243 | If you don't have \i{Gtk}, you should still be able to build the |
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244 | command-line tools. |
245 | |
246 | Note that Unix PuTTY has mostly only been tested on Linux so far; |
247 | portability problems such as BSD-style ptys or different header file |
248 | requirements are expected. |
249 | |
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250 | \S{faq-unix-why}{Question} What's the point of the Unix port? Unix |
251 | has OpenSSH. |
252 | |
253 | All sorts of little things. \c{pterm} is directly useful to anyone |
254 | who prefers PuTTY's terminal emulation to \c{xterm}'s, which at |
255 | least some people do. Unix Plink has apparently found a niche among |
256 | people who find the complexity of OpenSSL makes OpenSSH hard to |
257 | install (and who don't mind Plink not having as many features). Some |
258 | users want to generate a large number of SSH keys on Unix and then |
259 | copy them all into PuTTY, and the Unix PuTTYgen should allow them to |
260 | automate that conversion process. |
261 | |
262 | There were development advantages as well; porting PuTTY to Unix was |
263 | a valuable path-finding effort for other future ports, and also |
264 | allowed us to use the excellent Linux tool |
265 | \W{http://valgrind.kde.org/}{Valgrind} to help with debugging, which |
266 | has already improved PuTTY's stability on \e{all} platforms. |
267 | |
268 | However, if you're a Unix user and you can see no reason to switch |
269 | from OpenSSH to PuTTY/Plink, then you're probably right. We don't |
270 | expect our Unix port to be the right thing for everybody. |
271 | |
70cd2027 |
272 | \S{faq-wince}{Question} Will there be a port to Windows CE or PocketPC? |
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273 | |
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274 | We have done some work on such a port, but it only reached an early |
275 | stage, and certainly not a useful one. It's no longer being actively |
276 | worked on. |
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277 | |
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278 | However, there's a third-party port at |
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279 | \W{http://www.pocketputty.net/}\c{http://www.pocketputty.net/}. |
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280 | |
421406a4 |
281 | \S{faq-win31}{Question} Is there a port to \i{Windows 3.1}? |
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282 | |
283 | PuTTY is a 32-bit application from the ground up, so it won't run on |
284 | Windows 3.1 as a native 16-bit program; and it would be \e{very} |
285 | hard to port it to do so, because of Windows 3.1's vile memory |
286 | allocation mechanisms. |
287 | |
288 | However, it is possible in theory to compile the existing PuTTY |
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289 | source in such a way that it will run under \i{Win32s} (an extension to |
f82f00d0 |
290 | Windows 3.1 to let you run 32-bit programs). In order to do this |
291 | you'll need the right kind of C compiler - modern versions of Visual |
292 | C at least have stopped being backwards compatible to Win32s. Also, |
293 | the last time we tried this it didn't work very well. |
294 | |
295 | If you're interested in running PuTTY under Windows 3.1, help and |
296 | testing in this area would be very welcome! |
297 | |
421406a4 |
298 | \S{faq-mac-port}{Question} Will there be a port to the \I{Mac OS}Mac? |
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299 | |
d6214a56 |
300 | There are several answers to this question: |
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301 | |
d6214a56 |
302 | \b The Unix/Gtk port is already fully working under Mac OS X as an X11 |
303 | application. |
304 | |
99a2d7d4 |
305 | \b A native (Cocoa) Mac OS X port has been started. It's just about |
d6214a56 |
306 | usable, but is of nowhere near release quality yet, and is likely to |
99a2d7d4 |
307 | behave in unexpected ways. Currently it's unlikely to be completed |
308 | unless someone steps in to help. |
d6214a56 |
309 | |
310 | \b A separate port to the classic Mac OS (pre-OSX) is also in |
311 | progress; it too is not ready yet. |
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312 | |
a1d2976b |
313 | \S{faq-epoc}{Question} Will there be a port to EPOC? |
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314 | |
315 | I hope so, but given that ports aren't really progressing very fast |
316 | even on systems the developers \e{do} already know how to program |
317 | for, it might be a long time before any of us get round to learning |
318 | a new system and doing the port for that. |
319 | |
509afd76 |
320 | However, some of the work has been done by other people; see the |
321 | \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/links.html}{Links page of our website} |
322 | for various third-party ports. |
323 | |
324 | \S{faq-iphone}{Question} Will there be a port to the iPhone? |
325 | |
326 | We have no plans to write such a port ourselves; none of us has an |
327 | iPhone, and developing and publishing applications for it looks |
328 | awkward and expensive. Such a port would probably depend upon the |
329 | stalled Mac OS X port (see \k{faq-mac-port}). |
330 | |
331 | However, there is a third-party SSH client for the iPhone and |
332 | iPod\_Touch called \W{http://www.instantcocoa.com/products/pTerm/}{pTerm}, |
333 | which is apparently based on PuTTY. (This is nothing to do with our |
334 | similarly-named \c{pterm}, which is a standalone terminal emulator for |
335 | Unix systems; see \k{faq-unix}.) |
4f2fd423 |
336 | |
ee46ef84 |
337 | \H{faq-embedding} Embedding PuTTY in other programs |
338 | |
a1d2976b |
339 | \S{faq-dll}{Question} Is the SSH or Telnet code available as a DLL? |
ee46ef84 |
340 | |
341 | No, it isn't. It would take a reasonable amount of rewriting for |
342 | this to be possible, and since the PuTTY project itself doesn't |
343 | believe in DLLs (they make installation more error-prone) none of us |
344 | has taken the time to do it. |
345 | |
346 | Most of the code cleanup work would be a good thing to happen in |
347 | general, so if anyone feels like helping, we wouldn't say no. |
348 | |
cf46d5fb |
349 | See also |
350 | \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/dll-frontend.html}{the wishlist entry}. |
351 | |
a1d2976b |
352 | \S{faq-vb}{Question} Is the SSH or Telnet code available as a Visual |
70706890 |
353 | Basic component? |
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354 | |
355 | No, it isn't. None of the PuTTY team uses Visual Basic, and none of |
356 | us has any particular need to make SSH connections from a Visual |
357 | Basic application. In addition, all the preliminary work to turn it |
358 | into a DLL would be necessary first; and furthermore, we don't even |
359 | know how to write VB components. |
360 | |
361 | If someone offers to do some of this work for us, we might consider |
362 | it, but unless that happens I can't see VB integration being |
363 | anywhere other than the very bottom of our priority list. |
364 | |
a1d2976b |
365 | \S{faq-ipc}{Question} How can I use PuTTY to make an SSH connection |
70706890 |
366 | from within another program? |
ee46ef84 |
367 | |
368 | Probably your best bet is to use Plink, the command-line connection |
369 | tool. If you can start Plink as a second Windows process, and |
370 | arrange for your primary process to be able to send data to the |
371 | Plink process, and receive data from it, through pipes, then you |
372 | should be able to make SSH connections from your program. |
373 | |
374 | This is what CVS for Windows does, for example. |
375 | |
376 | \H{faq-details} Details of PuTTY's operation |
377 | |
421406a4 |
378 | \S{faq-term}{Question} What \i{terminal type} does PuTTY use? |
ee46ef84 |
379 | |
380 | For most purposes, PuTTY can be considered to be an \cw{xterm} |
32c37ecd |
381 | terminal. |
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382 | |
421406a4 |
383 | PuTTY also supports some terminal \i{control sequences} not supported by |
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384 | the real \cw{xterm}: notably the Linux console sequences that |
385 | reconfigure the colour palette, and the title bar control sequences |
421406a4 |
386 | used by \i\cw{DECterm} (which are different from the \cw{xterm} ones; |
ee46ef84 |
387 | PuTTY supports both). |
388 | |
389 | By default, PuTTY announces its terminal type to the server as |
390 | \c{xterm}. If you have a problem with this, you can reconfigure it |
391 | to say something else; \c{vt220} might help if you have trouble. |
392 | |
a1d2976b |
393 | \S{faq-settings}{Question} Where does PuTTY store its data? |
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394 | |
4c53784e |
395 | On Windows, PuTTY stores most of its data (saved sessions, SSH host |
421406a4 |
396 | keys) in the \i{Registry}. The precise location is |
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397 | |
398 | \c HKEY_CURRENT_USER\Software\SimonTatham\PuTTY |
399 | |
400 | and within that area, saved sessions are stored under \c{Sessions} |
401 | while host keys are stored under \c{SshHostKeys}. |
402 | |
403 | PuTTY also requires a random number seed file, to improve the |
404 | unpredictability of randomly chosen data needed as part of the SSH |
a628e2a9 |
405 | cryptography. This is stored by default in a file called \i\c{PUTTY.RND}; |
406 | this is stored by default in the \q{Application Data} directory, |
407 | or failing that, one of a number of fallback locations. If you |
c8f5c5c8 |
408 | want to change the location of the random number seed file, you can |
409 | put your chosen pathname in the Registry, at |
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410 | |
411 | \c HKEY_CURRENT_USER\Software\SimonTatham\PuTTY\RandSeedFile |
412 | |
c85de2c1 |
413 | You can ask PuTTY to delete all this data; see \k{faq-cleanup}. |
414 | |
4c53784e |
415 | On Unix, PuTTY stores all of this data in a directory \cw{~/.putty}. |
416 | |
ee46ef84 |
417 | \H{faq-howto} HOWTO questions |
418 | |
aecc2016 |
419 | \S{faq-login}{Question} What login name / password should I use? |
420 | |
421 | This is not a question you should be asking \e{us}. |
422 | |
423 | PuTTY is a communications tool, for making connections to other |
424 | computers. We maintain the tool; we \e{don't} administer any computers |
425 | that you're likely to be able to use, in the same way that the people |
426 | who make web browsers aren't responsible for most of the content you can |
427 | view in them. \#{FIXME: less technical analogy?} We cannot help with |
428 | questions of this sort. |
429 | |
430 | If you know the name of the computer you want to connect to, but don't |
431 | know what login name or password to use, you should talk to whoever |
432 | administers that computer. If you don't know who that is, see the next |
433 | question for some possible ways to find out. |
434 | |
435 | \# FIXME: some people ask us to provide them with a login name |
436 | apparently as random members of the public rather than in the |
437 | belief that we run a server belonging to an organisation they already |
438 | have some relationship with. Not sure what to say to such people. |
439 | |
421406a4 |
440 | \S{faq-commands}{Question} \I{commands on the server}What commands |
441 | can I type into my PuTTY terminal window? |
fe3d1229 |
442 | |
aecc2016 |
443 | Again, this is not a question you should be asking \e{us}. You need |
444 | to read the manuals, or ask the administrator, of \e{the computer |
445 | you have connected to}. |
fe3d1229 |
446 | |
447 | PuTTY does not process the commands you type into it. It's only a |
448 | communications tool. It makes a connection to another computer; it |
449 | passes the commands you type to that other computer; and it passes |
450 | the other computer's responses back to you. Therefore, the precise |
451 | range of commands you can use will not depend on PuTTY, but on what |
452 | kind of computer you have connected to and what software is running |
453 | on it. The PuTTY team cannot help you with that. |
454 | |
455 | (Think of PuTTY as being a bit like a telephone. If you phone |
456 | somebody up and you don't know what language to speak to make them |
457 | understand you, it isn't \e{the telephone company}'s job to find |
458 | that out for you. We just provide the means for you to get in touch; |
459 | making yourself understood is somebody else's problem.) |
460 | |
461 | If you are unsure of where to start looking for the administrator of |
462 | your server, a good place to start might be to remember how you |
463 | found out the host name in the PuTTY configuration. If you were |
464 | given that host name by e-mail, for example, you could try asking |
465 | the person who sent you that e-mail. If your company's IT department |
466 | provided you with ready-made PuTTY saved sessions, then that IT |
467 | department can probably also tell you something about what commands |
468 | you can type during those sessions. But the PuTTY maintainer team |
469 | does not administer any server you are likely to be connecting to, |
470 | and cannot help you with questions of this type. |
471 | |
421406a4 |
472 | \S{faq-startmax}{Question} How can I make PuTTY start up \i{maximise}d? |
ee46ef84 |
473 | |
474 | Create a Windows shortcut to start PuTTY from, and set it as \q{Run |
475 | Maximized}. |
476 | |
421406a4 |
477 | \S{faq-startsess}{Question} How can I create a \i{Windows shortcut} to |
70706890 |
478 | start a particular saved session directly? |
ee46ef84 |
479 | |
480 | To run a PuTTY session saved under the name \q{\cw{mysession}}, |
481 | create a Windows shortcut that invokes PuTTY with a command line |
482 | like |
483 | |
80969352 |
484 | \c \path\name\to\putty.exe -load "mysession" |
a58b605b |
485 | |
486 | (Note: prior to 0.53, the syntax was \c{@session}. This is now |
487 | deprecated and may be removed at some point.) |
ee46ef84 |
488 | |
a1d2976b |
489 | \S{faq-startssh}{Question} How can I start an SSH session straight |
70706890 |
490 | from the command line? |
ee46ef84 |
491 | |
492 | Use the command line \c{putty -ssh host.name}. Alternatively, create |
493 | a saved session that specifies the SSH protocol, and start the saved |
494 | session as shown in \k{faq-startsess}. |
495 | |
421406a4 |
496 | \S{faq-cutpaste}{Question} How do I \i{copy and paste} between PuTTY and |
70706890 |
497 | other Windows applications? |
ee46ef84 |
498 | |
499 | Copy and paste works similarly to the X Window System. You use the |
500 | left mouse button to select text in the PuTTY window. The act of |
501 | selection \e{automatically} copies the text to the clipboard: there |
502 | is no need to press Ctrl-Ins or Ctrl-C or anything else. In fact, |
503 | pressing Ctrl-C will send a Ctrl-C character to the other end of |
504 | your connection (just like it does the rest of the time), which may |
505 | have unpleasant effects. The \e{only} thing you need to do, to copy |
506 | text to the clipboard, is to select it. |
507 | |
508 | To paste the clipboard contents into a PuTTY window, by default you |
509 | click the right mouse button. If you have a three-button mouse and |
510 | are used to X applications, you can configure pasting to be done by |
511 | the middle button instead, but this is not the default because most |
512 | Windows users don't have a middle button at all. |
513 | |
514 | You can also paste by pressing Shift-Ins. |
515 | |
a1d2976b |
516 | \S{faq-options}{Question} How do I use all PuTTY's features (public |
a58b605b |
517 | keys, proxying, cipher selection, etc.) in PSCP, PSFTP and Plink? |
518 | |
519 | Most major features (e.g., public keys, port forwarding) are available |
520 | through command line options. See the documentation. |
72be5b5e |
521 | |
a58b605b |
522 | Not all features are accessible from the command line yet, although |
523 | we'd like to fix this. In the meantime, you can use most of |
72be5b5e |
524 | PuTTY's features if you create a PuTTY saved session, and then use |
525 | the name of the saved session on the command line in place of a |
526 | hostname. This works for PSCP, PSFTP and Plink (but don't expect |
527 | port forwarding in the file transfer applications!). |
f2003e32 |
528 | |
a1d2976b |
529 | \S{faq-pscp}{Question} How do I use PSCP.EXE? When I double-click it |
70706890 |
530 | gives me a command prompt window which then closes instantly. |
ee46ef84 |
531 | |
532 | PSCP is a command-line application, not a GUI application. If you |
533 | run it without arguments, it will simply print a help message and |
534 | terminate. |
535 | |
536 | To use PSCP properly, run it from a Command Prompt window. See |
537 | \k{pscp} in the documentation for more details. |
538 | |
421406a4 |
539 | \S{faq-pscp-spaces}{Question} \I{spaces in filenames}How do I use |
540 | PSCP to copy a file whose name has spaces in? |
ee46ef84 |
541 | |
542 | If PSCP is using the traditional SCP protocol, this is confusing. If |
543 | you're specifying a file at the local end, you just use one set of |
544 | quotes as you would normally do: |
545 | |
546 | \c pscp "local filename with spaces" user@host: |
547 | \c pscp user@host:myfile "local filename with spaces" |
548 | |
549 | But if the filename you're specifying is on the \e{remote} side, you |
550 | have to use backslashes and two sets of quotes: |
551 | |
552 | \c pscp user@host:"\"remote filename with spaces\"" local_filename |
553 | \c pscp local_filename user@host:"\"remote filename with spaces\"" |
554 | |
555 | Worse still, in a remote-to-local copy you have to specify the local |
556 | file name explicitly, otherwise PSCP will complain that they don't |
557 | match (unless you specified the \c{-unsafe} option). The following |
558 | command will give an error message: |
559 | |
560 | \c c:\>pscp user@host:"\"oo er\"" . |
e9cee352 |
561 | \c warning: remote host tried to write to a file called 'oo er' |
562 | \c when we requested a file called '"oo er"'. |
ee46ef84 |
563 | |
e9cee352 |
564 | Instead, you need to specify the local file name in full: |
565 | |
566 | \c c:\>pscp user@host:"\"oo er\"" "oo er" |
567 | |
ee46ef84 |
568 | If PSCP is using the newer SFTP protocol, none of this is a problem, |
569 | and all filenames with spaces in are specified using a single pair |
570 | of quotes in the obvious way: |
571 | |
572 | \c pscp "local file" user@host: |
573 | \c pscp user@host:"remote file" . |
574 | |
575 | \H{faq-trouble} Troubleshooting |
576 | |
babac7bd |
577 | \S{faq-incorrect-mac}{Question} Why do I see \q{Incorrect MAC |
578 | received on packet}? |
ee46ef84 |
579 | |
f348999d |
580 | One possible cause of this that used to be common is a bug in old |
2e85c969 |
581 | SSH-2 servers distributed by \cw{ssh.com}. (This is not the only |
f348999d |
582 | possible cause; see \k{errors-crc} in the documentation.) |
2e85c969 |
583 | Version 2.3.0 and below of their SSH-2 server |
ee46ef84 |
584 | constructs Message Authentication Codes in the wrong way, and |
585 | expects the client to construct them in the same wrong way. PuTTY |
586 | constructs the MACs correctly by default, and hence these old |
587 | servers will fail to work with it. |
588 | |
32c37ecd |
589 | If you are using PuTTY version 0.52 or better, this should work |
590 | automatically: PuTTY should detect the buggy servers from their |
591 | version number announcement, and automatically start to construct |
592 | its MACs in the same incorrect manner as they do, so it will be able |
593 | to work with them. |
ee46ef84 |
594 | |
32c37ecd |
595 | If you are using PuTTY version 0.51 or below, you can enable the |
596 | workaround by going to the SSH panel and ticking the box labelled |
e4c398b4 |
597 | \q{Imitate SSH2 MAC bug}. It's possible that you might have to do |
32c37ecd |
598 | this with 0.52 as well, if a buggy server exists that PuTTY doesn't |
599 | know about. |
ee46ef84 |
600 | |
421406a4 |
601 | In this context MAC stands for \ii{Message Authentication Code}. It's a |
b7e2c163 |
602 | cryptographic term, and it has nothing at all to do with Ethernet |
603 | MAC (Media Access Control) addresses. |
604 | |
67325335 |
605 | \S{faq-pscp-protocol}{Question} Why do I see \q{Fatal: Protocol |
606 | error: Expected control record} in PSCP? |
607 | |
608 | This happens because PSCP was expecting to see data from the server |
609 | that was part of the PSCP protocol exchange, and instead it saw data |
610 | that it couldn't make any sense of at all. |
611 | |
421406a4 |
612 | This almost always happens because the \i{startup scripts} in your |
67325335 |
613 | account on the server machine are generating output. This is |
614 | impossible for PSCP, or any other SCP client, to work around. You |
615 | should never use startup files (\c{.bashrc}, \c{.cshrc} and so on) |
616 | which generate output in non-interactive sessions. |
617 | |
618 | This is not actually a PuTTY problem. If PSCP fails in this way, |
619 | then all other SCP clients are likely to fail in exactly the same |
620 | way. The problem is at the server end. |
621 | |
421406a4 |
622 | \S{faq-colours}{Question} I clicked on a colour in the \ii{Colours} |
70706890 |
623 | panel, and the colour didn't change in my terminal. |
ee46ef84 |
624 | |
625 | That isn't how you're supposed to use the Colours panel. |
626 | |
627 | During the course of a session, PuTTY potentially uses \e{all} the |
628 | colours listed in the Colours panel. It's not a question of using |
629 | only one of them and you choosing which one; PuTTY will use them |
630 | \e{all}. The purpose of the Colours panel is to let you adjust the |
631 | appearance of all the colours. So to change the colour of the |
632 | cursor, for example, you would select \q{Cursor Colour}, press the |
633 | \q{Modify} button, and select a new colour from the dialog box that |
634 | appeared. Similarly, if you want your session to appear in green, |
635 | you should select \q{Default Foreground} and press \q{Modify}. |
636 | Clicking on \q{ANSI Green} won't turn your session green; it will |
637 | only allow you to adjust the \e{shade} of green used when PuTTY is |
638 | instructed by the server to display green text. |
639 | |
421406a4 |
640 | \S{faq-winsock2}{Question} Plink on \i{Windows 95} says it can't find |
641 | \i\cw{WS2_32.DLL}. |
ee46ef84 |
642 | |
643 | Plink requires the extended Windows network library, WinSock version |
644 | 2. This is installed as standard on Windows 98 and above, and on |
645 | Windows NT, and even on later versions of Windows 95; but early |
646 | Win95 installations don't have it. |
647 | |
648 | In order to use Plink on these systems, you will need to download |
649 | the |
650 | \W{http://www.microsoft.com/windows95/downloads/contents/wuadmintools/s_wunetworkingtools/w95sockets2/}{WinSock 2 upgrade}: |
651 | |
35cffede |
652 | \c http://www.microsoft.com/windows95/downloads/contents/ |
653 | \c wuadmintools/s_wunetworkingtools/w95sockets2/ |
ee46ef84 |
654 | |
2e85c969 |
655 | \S{faq-outofmem}{Question} After trying to establish an SSH-2 |
421406a4 |
656 | connection, PuTTY says \q{\ii{Out of memory}} and dies. |
ee46ef84 |
657 | |
658 | If this happens just while the connection is starting up, this often |
659 | indicates that for some reason the client and server have failed to |
660 | establish a session encryption key. Somehow, they have performed |
661 | calculations that should have given each of them the same key, but |
662 | have ended up with different keys; so data encrypted by one and |
663 | decrypted by the other looks like random garbage. |
664 | |
665 | This causes an \q{out of memory} error because the first encrypted |
666 | data PuTTY expects to see is the length of an SSH message. Normally |
667 | this will be something well under 100 bytes. If the decryption has |
668 | failed, PuTTY will see a completely random length in the region of |
669 | two \e{gigabytes}, and will try to allocate enough memory to store |
670 | this non-existent message. This will immediately lead to it thinking |
671 | it doesn't have enough memory, and panicking. |
672 | |
673 | If this happens to you, it is quite likely to still be a PuTTY bug |
674 | and you should report it (although it might be a bug in your SSH |
675 | server instead); but it doesn't necessarily mean you've actually run |
676 | out of memory. |
677 | |
9accb45d |
678 | \S{faq-outofmem2}{Question} When attempting a file transfer, either |
421406a4 |
679 | PSCP or PSFTP says \q{\ii{Out of memory}} and dies. |
9accb45d |
680 | |
421406a4 |
681 | This is almost always caused by your \i{login scripts} on the server |
9accb45d |
682 | generating output. PSCP or PSFTP will receive that output when they |
683 | were expecting to see the start of a file transfer protocol, and |
684 | they will attempt to interpret the output as file-transfer protocol. |
685 | This will usually lead to an \q{out of memory} error for much the |
686 | same reasons as given in \k{faq-outofmem}. |
687 | |
688 | This is a setup problem in your account on your server, \e{not} a |
689 | PSCP/PSFTP bug. Your login scripts should \e{never} generate output |
690 | during non-interactive sessions; secure file transfer is not the |
691 | only form of remote access that will break if they do. |
692 | |
693 | On Unix, a simple fix is to ensure that all the parts of your login |
694 | script that might generate output are in \c{.profile} (if you use a |
695 | Bourne shell derivative) or \c{.login} (if you use a C shell). |
696 | Putting them in more general files such as \c{.bashrc} or \c{.cshrc} |
697 | is liable to lead to problems. |
698 | |
7b24f677 |
699 | \S{faq-psftp-slow}{Question} PSFTP transfers files much slower than PSCP. |
9accb45d |
700 | |
b7280cfe |
701 | The throughput of PSFTP 0.54 should be much better than 0.53b and |
702 | prior; we've added code to the SFTP backend to queue several blocks |
703 | of data rather than waiting for an acknowledgement for each. (The |
704 | SCP backend did not suffer from this performance issue because SCP |
705 | is a much simpler protocol.) |
9accb45d |
706 | |
a1d2976b |
707 | \S{faq-bce}{Question} When I run full-colour applications, I see |
948c614b |
708 | areas of black space where colour ought to be, or vice versa. |
f1453e5c |
709 | |
421406a4 |
710 | You almost certainly need to change the \q{Use \i{background colour} to |
948c614b |
711 | erase screen} setting in the Terminal panel. If there is too much |
712 | black space (the commoner situation), you should enable it, while if |
713 | there is too much colour, you should disable it. (See \k{config-erase}.) |
714 | |
715 | In old versions of PuTTY, this was disabled by default, and would not |
716 | take effect until you reset the terminal (see \k{faq-resetterm}). |
717 | Since 0.54, it is enabled by default, and changes take effect |
718 | immediately. |
f1453e5c |
719 | |
a1d2976b |
720 | \S{faq-resetterm}{Question} When I change some terminal settings, |
70706890 |
721 | nothing happens. |
f1453e5c |
722 | |
421406a4 |
723 | Some of the terminal options (notably \ii{Auto Wrap} and |
f1453e5c |
724 | background-colour screen erase) actually represent the \e{default} |
725 | setting, rather than the currently active setting. The server can |
726 | send sequences that modify these options in mid-session, but when |
727 | the terminal is reset (by server action, or by you choosing \q{Reset |
728 | Terminal} from the System menu) the defaults are restored. |
729 | |
5bcf5d50 |
730 | In versions 0.53b and prior, if you change one of these options in |
731 | the middle of a session, you will find that the change does not |
732 | immediately take effect. It will only take effect once you reset |
733 | the terminal. |
734 | |
e6c7a73a |
735 | In version 0.54, the behaviour has changed - changes to these |
736 | settings take effect immediately. |
f1453e5c |
737 | |
a1d2976b |
738 | \S{faq-idleout}{Question} My PuTTY sessions unexpectedly close after |
421406a4 |
739 | they are \I{idle connections}idle for a while. |
ee46ef84 |
740 | |
421406a4 |
741 | Some types of \i{firewall}, and almost any router doing Network Address |
742 | Translation (\i{NAT}, also known as IP masquerading), will forget about |
ee46ef84 |
743 | a connection through them if the connection does nothing for too |
744 | long. This will cause the connection to be rudely cut off when |
745 | contact is resumed. |
746 | |
747 | You can try to combat this by telling PuTTY to send \e{keepalives}: |
748 | packets of data which have no effect on the actual session, but |
749 | which reassure the router or firewall that the network connection is |
750 | still active and worth remembering about. |
751 | |
752 | Keepalives don't solve everything, unfortunately; although they |
753 | cause greater robustness against this sort of router, they can also |
754 | cause a \e{loss} of robustness against network dropouts. See |
755 | \k{config-keepalive} in the documentation for more discussion of |
756 | this. |
757 | |
a1d2976b |
758 | \S{faq-timeout}{Question} PuTTY's network connections time out too |
421406a4 |
759 | quickly when \I{breaks in connectivity}network connectivity is |
760 | temporarily lost. |
ee46ef84 |
761 | |
762 | This is a Windows problem, not a PuTTY problem. The timeout value |
763 | can't be set on per application or per session basis. To increase |
764 | the TCP timeout globally, you need to tinker with the Registry. |
765 | |
8ac4ce9f |
766 | On Windows 95, 98 or ME, the registry key you need to create or |
767 | change is |
ee46ef84 |
768 | |
769 | \c HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\VxD\ |
770 | \c MSTCP\MaxDataRetries |
771 | |
772 | (it must be of type DWORD in Win95, or String in Win98/ME). |
8ac4ce9f |
773 | (See MS Knowledge Base article |
774 | \W{http://support.microsoft.com/default.aspx?scid=kb;en-us;158474}{158474} |
775 | for more information.) |
ee46ef84 |
776 | |
8e5037f6 |
777 | On Windows NT, 2000, or XP, the registry key to create or change is |
ee46ef84 |
778 | |
779 | \c HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\ |
780 | \c Parameters\TcpMaxDataRetransmissions |
781 | |
782 | and it must be of type DWORD. |
8e5037f6 |
783 | (See MS Knowledge Base articles |
8ac4ce9f |
784 | \W{http://support.microsoft.com/default.aspx?scid=kb;en-us;120642}{120642} |
8e5037f6 |
785 | and |
786 | \W{http://support.microsoft.com/default.aspx?scid=kb;en-us;314053}{314053} |
8ac4ce9f |
787 | for more information.) |
ee46ef84 |
788 | |
789 | Set the key's value to something like 10. This will cause Windows to |
790 | try harder to keep connections alive instead of abandoning them. |
791 | |
a1d2976b |
792 | \S{faq-puttyputty}{Question} When I \cw{cat} a binary file, I get |
b03dda39 |
793 | \q{PuTTYPuTTYPuTTY} on my command line. |
ee46ef84 |
794 | |
a5a6cb30 |
795 | Don't do that, then. |
ee46ef84 |
796 | |
797 | This is designed behaviour; when PuTTY receives the character |
798 | Control-E from the remote server, it interprets it as a request to |
799 | identify itself, and so it sends back the string \q{\cw{PuTTY}} as |
800 | if that string had been entered at the keyboard. Control-E should |
801 | only be sent by programs that are prepared to deal with the |
802 | response. Writing a binary file to your terminal is likely to output |
803 | many Control-E characters, and cause this behaviour. Don't do it. |
804 | It's a bad plan. |
805 | |
a5a6cb30 |
806 | To mitigate the effects, you could configure the answerback string |
807 | to be empty (see \k{config-answerback}); but writing binary files to |
808 | your terminal is likely to cause various other unpleasant behaviour, |
809 | so this is only a small remedy. |
810 | |
421406a4 |
811 | \S{faq-wintitle}{Question} When I \cw{cat} a binary file, my \i{window |
812 | title} changes to a nonsense string. |
ee46ef84 |
813 | |
a5a6cb30 |
814 | Don't do that, then. |
ee46ef84 |
815 | |
816 | It is designed behaviour that PuTTY should have the ability to |
817 | adjust the window title on instructions from the server. Normally |
818 | the control sequence that does this should only be sent |
819 | deliberately, by programs that know what they are doing and intend |
820 | to put meaningful text in the window title. Writing a binary file to |
821 | your terminal runs the risk of sending the same control sequence by |
822 | accident, and cause unexpected changes in the window title. Don't do |
823 | it. |
824 | |
e81024f9 |
825 | \S{faq-password-fails}{Question} My \i{keyboard} stops working once |
826 | PuTTY displays the \i{password prompt}. |
59c1f1f6 |
827 | |
828 | No, it doesn't. PuTTY just doesn't display the password you type, so |
829 | that someone looking at your screen can't see what it is. |
830 | |
831 | Unlike the Windows login prompts, PuTTY doesn't display the password |
832 | as a row of asterisks either. This is so that someone looking at |
833 | your screen can't even tell how \e{long} your password is, which |
834 | might be valuable information. |
835 | |
e81024f9 |
836 | \S{faq-keyboard}{Question} One or more \I{keyboard}\i{function keys} |
837 | don't do what I expected in a server-side application. |
b5bee048 |
838 | |
839 | If you've already tried all the relevant options in the PuTTY |
840 | Keyboard panel, you may need to mail the PuTTY maintainers and ask. |
841 | |
842 | It is \e{not} usually helpful just to tell us which application, |
843 | which server operating system, and which key isn't working; in order |
844 | to replicate the problem we would need to have a copy of every |
845 | operating system, and every application, that anyone has ever |
846 | complained about. |
847 | |
848 | PuTTY responds to function key presses by sending a sequence of |
849 | control characters to the server. If a function key isn't doing what |
850 | you expect, it's likely that the character sequence your application |
851 | is expecting to receive is not the same as the one PuTTY is sending. |
852 | Therefore what we really need to know is \e{what} sequence the |
853 | application is expecting. |
854 | |
855 | The simplest way to investigate this is to find some other terminal |
856 | environment, in which that function key \e{does} work; and then |
857 | investigate what sequence the function key is sending in that |
e81024f9 |
858 | situation. One reasonably easy way to do this on a \i{Unix} system is to |
859 | type the command \i\c{cat}, and then press the function key. This is |
b5bee048 |
860 | likely to produce output of the form \c{^[[11~}. You can also do |
861 | this in PuTTY, to find out what sequence the function key is |
862 | producing in that. Then you can mail the PuTTY maintainers and tell |
863 | us \q{I wanted the F1 key to send \c{^[[11~}, but instead it's |
864 | sending \c{^[OP}, can this be done?}, or something similar. |
865 | |
866 | You should still read the |
867 | \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/feedback.html}{Feedback |
868 | page} on the PuTTY website (also provided as \k{feedback} in the |
869 | manual), and follow the guidelines contained in that. |
870 | |
941d39e2 |
871 | \S{faq-openssh-bad-openssl}{Question} Since my SSH server was upgraded |
421406a4 |
872 | to \i{OpenSSH} 3.1p1/3.4p1, I can no longer connect with PuTTY. |
1d2a9c9c |
873 | |
874 | There is a known problem when OpenSSH has been built against an |
875 | incorrect version of OpenSSL; the quick workaround is to configure |
876 | PuTTY to use SSH protocol 2 and the Blowfish cipher. |
877 | |
941d39e2 |
878 | For more details and OpenSSH patches, see |
879 | \W{http://bugzilla.mindrot.org/show_bug.cgi?id=138}{bug 138} in the |
880 | OpenSSH BTS. |
881 | |
1d2a9c9c |
882 | This is not a PuTTY-specific problem; if you try to connect with |
941d39e2 |
883 | another client you'll likely have similar problems. (Although PuTTY's |
884 | default cipher differs from many other clients.) |
1d2a9c9c |
885 | |
941d39e2 |
886 | \e{OpenSSH 3.1p1:} configurations known to be broken (and symptoms): |
1d2a9c9c |
887 | |
3a115fdd |
888 | \b SSH-2 with AES cipher (PuTTY says \q{Assertion failed! Expression: |
889 | (len & 15) == 0} in \cw{sshaes.c}, or \q{Out of memory}, or crashes) |
1d2a9c9c |
890 | |
3a115fdd |
891 | \b SSH-2 with 3DES (PuTTY says \q{Incorrect MAC received on packet}) |
9712b085 |
892 | |
3a115fdd |
893 | \b SSH-1 with Blowfish (PuTTY says \q{Incorrect CRC received on |
894 | packet}) |
1d2a9c9c |
895 | |
2e85c969 |
896 | \b SSH-1 with 3DES |
1d2a9c9c |
897 | |
2e85c969 |
898 | \e{OpenSSH 3.4p1:} as of 3.4p1, only the problem with SSH-1 and |
941d39e2 |
899 | Blowfish remains. Rebuild your server, apply the patch linked to from |
900 | bug 138 above, or use another cipher (e.g., 3DES) instead. |
59f76022 |
901 | |
46ccbe20 |
902 | \e{Other versions:} we occasionally get reports of the same symptom |
903 | and workarounds with older versions of OpenSSH, although it's not |
904 | clear the underlying cause is the same. |
905 | |
3a115fdd |
906 | \S{faq-ssh2key-ssh1conn}{Question} Why do I see \q{Couldn't load |
907 | private key from ...}? Why can PuTTYgen load my key but not PuTTY? |
1bb76745 |
908 | |
909 | It's likely that you've generated an SSH protocol 2 key with PuTTYgen, |
2e85c969 |
910 | but you're trying to use it in an SSH-1 connection. SSH-1 and SSH-2 keys |
1bb76745 |
911 | have different formats, and (at least in 0.52) PuTTY's reporting of a |
912 | key in the wrong format isn't optimal. |
913 | |
2e85c969 |
914 | To connect using SSH-2 to a server that supports both versions, you |
1bb76745 |
915 | need to change the configuration from the default (see \k{faq-ssh2}). |
916 | |
421406a4 |
917 | \S{faq-rh8-utf8}{Question} When I'm connected to a \i{Red Hat Linux} 8.0 |
2c4b913d |
918 | system, some characters don't display properly. |
919 | |
920 | A common complaint is that hyphens in man pages show up as a-acute. |
921 | |
421406a4 |
922 | With release 8.0, Red Hat appear to have made \i{UTF-8} the default |
2c4b913d |
923 | character set. There appears to be no way for terminal emulators such |
924 | as PuTTY to know this (as far as we know, the appropriate escape |
925 | sequence to switch into UTF-8 mode isn't sent). |
926 | |
927 | A fix is to configure sessions to RH8 systems to use UTF-8 |
928 | translation - see \k{config-charset} in the documentation. (Note that |
929 | if you use \q{Change Settings}, changes may not take place immediately |
930 | - see \k{faq-resetterm}.) |
931 | |
932 | If you really want to change the character set used by the server, the |
933 | right place is \c{/etc/sysconfig/i18n}, but this shouldn't be |
934 | necessary. |
935 | |
b86e68d8 |
936 | \S{faq-screen}{Question} Since I upgraded to PuTTY 0.54, the |
937 | scrollback has stopped working when I run \c{screen}. |
938 | |
939 | PuTTY's terminal emulator has always had the policy that when the |
421406a4 |
940 | \q{\i{alternate screen}} is in use, nothing is added to the scrollback. |
b86e68d8 |
941 | This is because the usual sorts of programs which use the alternate |
942 | screen are things like text editors, which tend to scroll back and |
943 | forth in the same document a lot; so (a) they would fill up the |
944 | scrollback with a large amount of unhelpfully disordered text, and |
945 | (b) they contain their \e{own} method for the user to scroll back to |
946 | the bit they were interested in. We have generally found this policy |
947 | to do the Right Thing in almost all situations. |
948 | |
949 | Unfortunately, \c{screen} is one exception: it uses the alternate |
950 | screen, but it's still usually helpful to have PuTTY's scrollback |
951 | continue working. The simplest solution is to go to the Features |
952 | control panel and tick \q{Disable switching to alternate terminal |
953 | screen}. (See \k{config-features-altscreen} for more details.) |
f08afc59 |
954 | Alternatively, you can tell \c{screen} itself not to use the |
955 | alternate screen: the |
956 | \W{http://www4.informatik.uni-erlangen.de/~jnweiger/screen-faq.html}{\c{screen} |
957 | FAQ} suggests adding the line \cq{termcapinfo xterm ti@:te@} to your |
958 | \cw{.screenrc} file. |
b86e68d8 |
959 | |
960 | The reason why this only started to be a problem in 0.54 is because |
961 | \c{screen} typically uses an unusual control sequence to switch to |
962 | the alternate screen, and previous versions of PuTTY did not support |
963 | this sequence. |
964 | |
421406a4 |
965 | \S{faq-alternate-localhost}{Question} Since I upgraded \i{Windows XP} |
85c598bf |
966 | to Service Pack 2, I can't use addresses like \cw{127.0.0.2}. |
967 | |
421406a4 |
968 | Some people who ask PuTTY to listen on \i{localhost} addresses other |
969 | than \cw{127.0.0.1} to forward services such as \i{SMB} and \i{Windows |
970 | Terminal Services} have found that doing so no longer works since |
85c598bf |
971 | they upgraded to WinXP SP2. |
972 | |
0a05eecb |
973 | This is apparently an issue with SP2 that is acknowledged by Microsoft |
974 | in MS Knowledge Base article |
85c598bf |
975 | \W{http://support.microsoft.com/default.aspx?scid=kb;en-us;884020}{884020}. |
a510ac14 |
976 | The article links to a fix you can download. |
85c598bf |
977 | |
5ac88186 |
978 | (\e{However}, we've been told that SP2 \e{also} fixes the bug that |
979 | means you need to use non-\cw{127.0.0.1} addresses to forward |
000cae2e |
980 | Terminal Services in the first place.) |
5ac88186 |
981 | |
811527db |
982 | \S{faq-missing-slash}{Question} PSFTP commands seem to be missing a |
983 | directory separator (slash). |
984 | |
985 | Some people have reported the following incorrect behaviour with |
986 | PSFTP: |
987 | |
988 | \c psftp> pwd |
989 | \e iii |
990 | \c Remote directory is /dir1/dir2 |
991 | \c psftp> get filename.ext |
992 | \e iiiiiiiiiiiiiiii |
993 | \c /dir1/dir2filename.ext: no such file or directory |
994 | |
995 | This is not a bug in PSFTP. There is a known bug in some versions of |
421406a4 |
996 | portable \i{OpenSSH} |
811527db |
997 | (\W{http://bugzilla.mindrot.org/show_bug.cgi?id=697}{bug 697}) that |
998 | causes these symptoms; it appears to have been introduced around |
999 | 3.7.x. It manifests only on certain platforms (AIX is what has been |
1000 | reported to us). |
1001 | |
1002 | There is a patch for OpenSSH attached to that bug; it's also fixed in |
1003 | recent versions of portable OpenSSH (from around 3.8). |
1004 | |
b493cd11 |
1005 | \S{faq-connaborted}{Question} Do you want to hear about \q{Software |
1006 | caused connection abort}? |
6b39d356 |
1007 | |
1008 | In the documentation for PuTTY 0.53 and 0.53b, we mentioned that we'd |
1009 | like to hear about any occurrences of this error. Since the release |
1010 | of PuTTY 0.54, however, we've been convinced that this error doesn't |
1011 | indicate that PuTTY's doing anything wrong, and we don't need to hear |
1012 | about further occurrences. See \k{errors-connaborted} for our current |
1013 | documentation of this error. |
1014 | |
3ba2d921 |
1015 | \S{faq-rekey}{Question} My SSH-2 session \I{locking up, SSH-2 |
1016 | sessions}locks up for a few seconds every so often. |
1017 | |
1018 | Recent versions of PuTTY automatically initiate \i{repeat key |
1019 | exchange} once per hour, to improve session security. If your client |
1020 | or server machine is slow, you may experience this as a delay of |
1021 | anything up to thirty seconds or so. |
1022 | |
1023 | These \I{delays, in SSH-2 sessions}delays are inconvenient, but they |
1024 | are there for your protection. If they really cause you a problem, |
1025 | you can choose to turn off periodic rekeying using the \q{Kex} |
1026 | configuration panel (see \k{config-ssh-kex}), but be aware that you |
1027 | will be sacrificing security for this. (Falling back to SSH-1 would |
1028 | also remove the delays, but would lose a \e{lot} more security |
1029 | still. We do not recommend it.) |
1030 | |
7090f35e |
1031 | \S{faq-xpwontrun}{Question} PuTTY fails to start up. Windows claims that |
1032 | \q{the application configuration is incorrect}. |
1033 | |
b4537635 |
1034 | This is caused by a bug in certain versions of \i{Windows XP} which |
1035 | is triggered by PuTTY 0.58. This was fixed in 0.59. The |
7090f35e |
1036 | \W{http://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/xp-wont-run}{\q{xp-wont-run}} |
1037 | entry in PuTTY's wishlist has more details. |
1038 | |
ee46ef84 |
1039 | \H{faq-secure} Security questions |
1040 | |
a1d2976b |
1041 | \S{faq-publicpc}{Question} Is it safe for me to download PuTTY and |
70706890 |
1042 | use it on a public PC? |
ee46ef84 |
1043 | |
1044 | It depends on whether you trust that PC. If you don't trust the |
1045 | public PC, don't use PuTTY on it, and don't use any other software |
1046 | you plan to type passwords into either. It might be watching your |
1047 | keystrokes, or it might tamper with the PuTTY binary you download. |
1048 | There is \e{no} program safe enough that you can run it on an |
1049 | actively malicious PC and get away with typing passwords into it. |
1050 | |
1051 | If you do trust the PC, then it's probably OK to use PuTTY on it |
1052 | (but if you don't trust the network, then the PuTTY download might |
1053 | be tampered with, so it would be better to carry PuTTY with you on a |
1054 | floppy). |
1055 | |
a1d2976b |
1056 | \S{faq-cleanup}{Question} What does PuTTY leave on a system? How can |
421406a4 |
1057 | I \i{clean up} after it? |
ee46ef84 |
1058 | |
1059 | PuTTY will leave some Registry entries, and a random seed file, on |
1060 | the PC (see \k{faq-settings}). If you are using PuTTY on a public |
1061 | PC, or somebody else's PC, you might want to clean these up when you |
1062 | leave. You can do that automatically, by running the command |
9310cb7d |
1063 | \c{putty -cleanup}. (Note that this only removes settings for |
1064 | the currently logged-in user on \i{multi-user systems}.) |
1065 | |
1066 | If PuTTY was installed from the installer package, it will also |
c35ff6c8 |
1067 | appear in \q{Add/Remove Programs}. Older versions of the uninstaller |
1068 | do not remove the above-mentioned registry entries and file. |
ee46ef84 |
1069 | |
421406a4 |
1070 | \S{faq-dsa}{Question} How come PuTTY now supports \i{DSA}, when the |
70706890 |
1071 | website used to say how insecure it was? |
ee46ef84 |
1072 | |
1073 | DSA has a major weakness \e{if badly implemented}: it relies on a |
1074 | random number generator to far too great an extent. If the random |
1075 | number generator produces a number an attacker can predict, the DSA |
1076 | private key is exposed - meaning that the attacker can log in as you |
1077 | on all systems that accept that key. |
1078 | |
1079 | The PuTTY policy changed because the developers were informed of |
1080 | ways to implement DSA which do not suffer nearly as badly from this |
1081 | weakness, and indeed which don't need to rely on random numbers at |
1082 | all. For this reason we now believe PuTTY's DSA implementation is |
1083 | probably OK. However, if you have the choice, we still recommend you |
1084 | use RSA instead. |
1085 | |
ee4b471f |
1086 | \S{faq-virtuallock}{Question} Couldn't Pageant use |
1087 | \cw{VirtualLock()} to stop private keys being written to disk? |
f9908cf7 |
1088 | |
ee4b471f |
1089 | Unfortunately not. The \cw{VirtualLock()} function in the Windows |
1090 | API doesn't do a proper job: it may prevent small pieces of a |
1091 | process's memory from being paged to disk while the process is |
1092 | running, but it doesn't stop the process's memory as a whole from |
1093 | being swapped completely out to disk when the process is long-term |
1094 | inactive. And Pageant spends most of its time inactive. |
f9908cf7 |
1095 | |
ee46ef84 |
1096 | \H{faq-admin} Administrative questions |
1097 | |
a1d2976b |
1098 | \S{faq-domain}{Question} Would you like me to register you a nicer |
70706890 |
1099 | domain name? |
ee46ef84 |
1100 | |
1101 | No, thank you. Even if you can find one (most of them seem to have |
1102 | been registered already, by people who didn't ask whether we |
1103 | actually wanted it before they applied), we're happy with the PuTTY |
1104 | web site being exactly where it is. It's not hard to find (just type |
1105 | \q{putty} into \W{http://www.google.com/}{google.com} and we're the |
1106 | first link returned), and we don't believe the administrative hassle |
1107 | of moving the site would be worth the benefit. |
1108 | |
1109 | In addition, if we \e{did} want a custom domain name, we would want |
1110 | to run it ourselves, so we knew for certain that it would continue |
1111 | to point where we wanted it, and wouldn't suddenly change or do |
1112 | strange things. Having it registered for us by a third party who we |
1113 | don't even know is not the best way to achieve this. |
1114 | |
a1d2976b |
1115 | \S{faq-webhosting}{Question} Would you like free web hosting for the |
70706890 |
1116 | PuTTY web site? |
ee46ef84 |
1117 | |
1118 | We already have some, thanks. |
1119 | |
34185d04 |
1120 | \S{faq-link}{Question} Would you link to my web site from the PuTTY |
1121 | web site? |
1122 | |
1123 | Only if the content of your web page is of definite direct interest |
1124 | to PuTTY users. If your content is unrelated, or only tangentially |
1125 | related, to PuTTY, then the link would simply be advertising for |
1126 | you. |
1127 | |
1128 | One very nice effect of the Google ranking mechanism is that by and |
1129 | large, the most popular web sites get the highest rankings. This |
1130 | means that when an ordinary person does a search, the top item in |
1131 | the search is very likely to be a high-quality site or the site they |
1132 | actually wanted, rather than the site which paid the most money for |
1133 | its ranking. |
1134 | |
1135 | The PuTTY web site is held in high esteem by Google, for precisely |
1136 | this reason: lots of people have linked to it simply because they |
1137 | like PuTTY, without us ever having to ask anyone to link to us. We |
1138 | feel that it would be an abuse of this esteem to use it to boost the |
1139 | ranking of random advertisers' web sites. If you want your web site |
1140 | to have a high Google ranking, we'd prefer that you achieve this the |
1141 | way we did - by being good enough at what you do that people will |
1142 | link to you simply because they like you. |
1143 | |
b609f258 |
1144 | In particular, we aren't interested in trading links for money (see |
1145 | above), and we \e{certainly} aren't interested in trading links for |
1146 | other links (since we have no advertising on our web site, our |
1147 | Google ranking is not even directly worth anything to us). If we |
1148 | don't want to link to you for free, then we probably won't want to |
1149 | link to you at all. |
1150 | |
34185d04 |
1151 | If you have software based on PuTTY, or specifically designed to |
1152 | interoperate with PuTTY, or in some other way of genuine interest to |
1153 | PuTTY users, then we will probably be happy to add a link to you on |
99d1a50e |
1154 | our Links page. And if you're running a particularly valuable mirror |
1155 | of the PuTTY web site, we might be interested in linking to you from |
1156 | our Mirrors page. |
34185d04 |
1157 | |
a1d2976b |
1158 | \S{faq-sourceforge}{Question} Why don't you move PuTTY to |
70706890 |
1159 | SourceForge? |
ee46ef84 |
1160 | |
1161 | Partly, because we don't want to move the web site location (see |
1162 | \k{faq-domain}). |
1163 | |
1164 | Also, security reasons. PuTTY is a security product, and as such it |
1165 | is particularly important to guard the code and the web site against |
1166 | unauthorised modifications which might introduce subtle security |
51e759ee |
1167 | flaws. Therefore, we prefer that the Subversion repository, web site and |
ee46ef84 |
1168 | FTP site remain where they are, under the direct control of system |
1169 | administrators we know and trust personally, rather than being run |
1170 | by a large organisation full of people we've never met and which is |
1171 | known to have had breakins in the past. |
1172 | |
1173 | No offence to SourceForge; I think they do a wonderful job. But |
1174 | they're not ideal for everyone, and in particular they're not ideal |
1175 | for us. |
1176 | |
a1d2976b |
1177 | \S{faq-mailinglist1}{Question} Why can't I subscribe to the |
70706890 |
1178 | putty-bugs mailing list? |
ee46ef84 |
1179 | |
1180 | Because you're not a member of the PuTTY core development team. The |
1181 | putty-bugs mailing list is not a general newsgroup-like discussion |
1182 | forum; it's a contact address for the core developers, and an |
1183 | \e{internal} mailing list for us to discuss things among ourselves. |
1184 | If we opened it up for everybody to subscribe to, it would turn into |
1185 | something more like a newsgroup and we would be completely |
1186 | overwhelmed by the volume of traffic. It's hard enough to keep up |
1187 | with the list as it is. |
1188 | |
a1d2976b |
1189 | \S{faq-mailinglist2}{Question} If putty-bugs isn't a |
70706890 |
1190 | general-subscription mailing list, what is? |
ee46ef84 |
1191 | |
1192 | There isn't one, that we know of. |
1193 | |
be86e512 |
1194 | If someone else wants to set up a mailing list or other forum for |
1195 | PuTTY users to help each other with common problems, that would be |
1196 | fine with us, though the PuTTY team would almost certainly not have the |
87b461db |
1197 | time to read it. It's probably better to use one of the established |
1198 | newsgroups for this purpose (see \k{feedback-other-fora}). |
ee46ef84 |
1199 | |
a1d2976b |
1200 | \S{faq-donations}{Question} How can I donate to PuTTY development? |
ee46ef84 |
1201 | |
1202 | Please, \e{please} don't feel you have to. PuTTY is completely free |
1203 | software, and not shareware. We think it's very important that |
1204 | \e{everybody} who wants to use PuTTY should be able to, whether they |
1205 | have any money or not; so the last thing we would want is for a |
1206 | PuTTY user to feel guilty because they haven't paid us any money. If |
1207 | you want to keep your money, please do keep it. We wouldn't dream of |
1208 | asking for any. |
1209 | |
1210 | Having said all that, if you still really \e{want} to give us money, |
1211 | we won't argue :-) The easiest way for us to accept donations is if |
2244ea7b |
1212 | you send money to \cw{<anakin@pobox.com>} using PayPal |
d3b774ba |
1213 | (\W{http://www.paypal.com/}\cw{www.paypal.com}). If you don't like |
1214 | PayPal, talk to us; we can probably arrange some alternative means. |
ee46ef84 |
1215 | |
1216 | Small donations (tens of dollars or tens of euros) will probably be |
1217 | spent on beer or curry, which helps motivate our volunteer team to |
1218 | continue doing this for the world. Larger donations will be spent on |
1219 | something that actually helps development, if we can find anything |
9cd3f7b0 |
1220 | (perhaps new hardware, or a copy of Windows XP), but if we can't |
ee46ef84 |
1221 | find anything then we'll just distribute the money among the |
1222 | developers. If you want to be sure your donation is going towards |
1223 | something worthwhile, ask us first. If you don't like these terms, |
1224 | feel perfectly free not to donate. We don't mind. |
1225 | |
150ef9c6 |
1226 | \S{faq-permission}{Question} Can I have permission to put PuTTY on a |
1227 | cover disk / distribute it with other software / etc? |
1228 | |
30a6b820 |
1229 | Yes. For most things, you need not bother asking us explicitly for |
1230 | permission; our licence already grants you permission. |
1231 | |
1232 | See \k{feedback-permission} for more details. |
150ef9c6 |
1233 | |
6894fbe1 |
1234 | \S{faq-indemnity}{Question} Can you sign an agreement indemnifying |
1235 | us against security problems in PuTTY? |
1236 | |
1237 | No! |
1238 | |
1239 | A vendor of physical security products (e.g. locks) might plausibly |
1240 | be willing to accept financial liability for a product that failed |
1241 | to perform as advertised and resulted in damage (e.g. valuables |
1242 | being stolen). The reason they can afford to do this is because they |
1243 | sell a \e{lot} of units, and only a small proportion of them will |
1244 | fail; so they can meet their financial liability out of the income |
1245 | from all the rest of their sales, and still have enough left over to |
1246 | make a profit. Financial liability is intrinsically linked to |
1247 | selling your product for money. |
1248 | |
1249 | There are two reasons why PuTTY is not analogous to a physical lock |
1250 | in this context. One is that software products don't exhibit random |
1251 | variation: \e{if} PuTTY has a security hole (which does happen, |
1252 | although we do our utmost to prevent it and to respond quickly when |
1253 | it does), every copy of PuTTY will have the same hole, so it's |
1254 | likely to affect all the users at the same time. So even if our |
1255 | users were all paying us to use PuTTY, we wouldn't be able to |
1256 | \e{simultaneously} pay every affected user compensation in excess of |
1257 | the amount they had paid us in the first place. It just wouldn't |
1258 | work. |
1259 | |
1260 | The second, much more important, reason is that PuTTY users |
1261 | \e{don't} pay us. The PuTTY team does not have an income; it's a |
1262 | volunteer effort composed of people spending their spare time to try |
1263 | to write useful software. We aren't even a company or any kind of |
1264 | legally recognised organisation. We're just a bunch of people who |
1265 | happen to do some stuff in our spare time. |
1266 | |
1267 | Therefore, to ask us to assume financial liability is to ask us to |
1268 | assume a risk of having to pay it out of our own \e{personal} |
1269 | pockets: out of the same budget from which we buy food and clothes |
1270 | and pay our rent. That's more than we're willing to give. We're |
1271 | already giving a lot of our spare \e{time} to developing software |
1272 | for free; if we had to pay our own \e{money} to do it as well, we'd |
1273 | start to wonder why we were bothering. |
1274 | |
1275 | Free software fundamentally does not work on the basis of financial |
1276 | guarantees. Your guarantee of the software functioning correctly is |
1277 | simply that you have the source code and can check it before you use |
1278 | it. If you want to be sure there aren't any security holes, do a |
1279 | security audit of the PuTTY code, or hire a security engineer if you |
1280 | don't have the necessary skills yourself: instead of trying to |
1281 | ensure you can get compensation in the event of a disaster, try to |
1282 | ensure there isn't a disaster in the first place. |
1283 | |
1284 | If you \e{really} want financial security, see if you can find a |
1285 | security engineer who will take financial responsibility for the |
1286 | correctness of their review. (This might be less likely to suffer |
1287 | from the everything-failing-at-once problem mentioned above, because |
1288 | such an engineer would probably be reviewing a lot of \e{different} |
1289 | products which would tend to fail independently.) Failing that, see |
1290 | if you can persuade an insurance company to insure you against |
1291 | security incidents, and if the insurer demands it as a condition |
1292 | then get our code reviewed by a security engineer they're happy |
1293 | with. |
1294 | |
1295 | \S{faq-permission-form}{Question} Can you sign this form granting us |
1296 | permission to use/distribute PuTTY? |
1297 | |
1298 | If your form contains any clause along the lines of \q{the |
1299 | undersigned represents and warrants}, we're not going to sign it. |
1300 | This is particularly true if it asks us to warrant that PuTTY is |
1301 | secure; see \k{faq-indemnity} for more discussion of this. But it |
1302 | doesn't really matter what we're supposed to be warranting: even if |
1303 | it's something we already believe is true, such as that we don't |
1304 | infringe any third-party copyright, we will not sign a document |
1305 | accepting any legal or financial liability. This is simply because |
1306 | the PuTTY development project has no income out of which to satisfy |
1307 | that liability, or pay legal costs, should it become necessary. We |
1308 | cannot afford to be sued. We are assuring you that \e{we have done |
1309 | our best}; if that isn't good enough for you, tough. |
1310 | |
1311 | The existing PuTTY licence document already gives you permission to |
1312 | use or distribute PuTTY in pretty much any way which does not |
1313 | involve pretending you wrote it or suing us if it goes wrong. We |
1314 | think that really ought to be enough for anybody. |
1315 | |
1316 | See also \k{faq-permission-general} for another reason why we don't |
1317 | want to do this sort of thing. |
1318 | |
1319 | \S{faq-permission-future}{Question} Can you write us a formal notice |
1320 | of permission to use PuTTY? |
1321 | |
1322 | We could, in principle, but it isn't clear what use it would be. If |
1323 | you think there's a serious chance of one of the PuTTY copyright |
1324 | holders suing you (which we don't!), you would presumably want a |
1325 | signed notice from \e{all} of them; and we couldn't provide that |
1326 | even if we wanted to, because many of the copyright holders are |
1327 | people who contributed some code in the past and with whom we |
1328 | subsequently lost contact. Therefore the best we would be able to do |
1329 | \e{even in theory} would be to have the core development team sign |
1330 | the document, which wouldn't guarantee you that some other copyright |
1331 | holder might not sue. |
1332 | |
1333 | See also \k{faq-permission-general} for another reason why we don't |
1334 | want to do this sort of thing. |
1335 | |
1336 | \S{faq-permission-general}{Question} Can you sign \e{anything} for |
1337 | us? |
1338 | |
1339 | Not unless there's an incredibly good reason. |
1340 | |
1341 | We are generally unwilling to set a precedent that involves us |
1342 | having to enter into individual agreements with PuTTY users. We |
1343 | estimate that we have literally \e{millions} of users, and we |
1344 | absolutely would not have time to go round signing specific |
1345 | agreements with every one of them. So if you want us to sign |
1346 | something specific for you, you might usefully stop to consider |
1347 | whether there's anything special that distinguishes you from 999,999 |
1348 | other users, and therefore any reason we should be willing to sign |
1349 | something for you without it setting such a precedent. |
1350 | |
1351 | If your company policy requires you to have an individual agreement |
1352 | with the supplier of any software you use, then your company policy |
1353 | is simply not well suited to using popular free software, and we |
1354 | urge you to consider this as a flaw in your policy. |
1355 | |
1356 | \S{faq-permission-assurance}{Question} If you won't sign anything, |
1357 | can you give us some sort of assurance that you won't make PuTTY |
1358 | closed-source in future? |
1359 | |
1360 | Yes and no. |
1361 | |
1362 | If what you want is an assurance that some \e{current version} of |
1363 | PuTTY which you've already downloaded will remain free, then you |
1364 | already have that assurance: it's called the PuTTY Licence. It |
1365 | grants you permission to use, distribute and copy the software to |
1366 | which it applies; once we've granted that permission (which we |
1367 | have), we can't just revoke it. |
1368 | |
1369 | On the other hand, if you want an assurance that \e{future} versions |
1370 | of PuTTY won't be closed-source, that's more difficult. We could in |
1371 | principle sign a document stating that we would never release a |
1372 | closed-source PuTTY, but that wouldn't assure you that we \e{would} |
1373 | keep releasing \e{open}-source PuTTYs: we would still have the |
1374 | option of ceasing to develop PuTTY at all, which would surely be |
1375 | even worse for you than making it closed-source! (And we almost |
1376 | certainly wouldn't \e{want} to sign a document guaranteeing that we |
1377 | would actually continue to do development work on PuTTY; we |
1378 | certainly wouldn't sign it for free. Documents like that are called |
1379 | contracts of employment, and are generally not signed except in |
1380 | return for a sizeable salary.) |
1381 | |
1382 | If we \e{were} to stop developing PuTTY, or to decide to make all |
1383 | future releases closed-source, then you would still be free to copy |
1384 | the last open release in accordance with the current licence, and in |
1385 | particular you could start your own fork of the project from that |
1386 | release. If this happened, I confidently predict that \e{somebody} |
1387 | would do that, and that some kind of a free PuTTY would continue to |
1388 | be developed. There's already precedent for that sort of thing |
1389 | happening in free software. We can't guarantee that somebody |
1390 | \e{other than you} would do it, of course; you might have to do it |
1391 | yourself. But we can assure you that there would be nothing |
1392 | \e{preventing} anyone from continuing free development if we |
1393 | stopped. |
1394 | |
1395 | (Finally, we can also confidently predict that if we made PuTTY |
1396 | closed-source and someone made an open-source fork, most people |
1397 | would switch to the latter. Therefore, it would be pretty stupid of |
1398 | us to try it.) |
1399 | |
84889c2c |
1400 | \S{faq-export-cert}{Question} Can you provide us with export control |
1401 | information / FIPS certification for PuTTY? |
1402 | |
1403 | Some people have asked us for an Export Control Classification Number |
1404 | (ECCN) for PuTTY. We don't know whether we have one, and as a team of |
1405 | free software developers based in the UK we don't have the time, |
1406 | money, or effort to deal with US bureaucracy to investigate any |
1407 | further. We believe that PuTTY falls under 5D002 on the US Commerce |
1408 | Control List, but that shouldn't be taken as definitive. If you need |
1409 | to know more you should seek professional legal advice. The same |
1410 | applies to any other country's legal requirements and restrictions. |
1411 | |
1412 | Similarly, some people have asked us for FIPS certification of the |
1413 | PuTTY tools. Unless someone else is prepared to do the necessary work |
1414 | and pay any costs, we can't provide this. |
1415 | |
f9908cf7 |
1416 | \H{faq-misc} Miscellaneous questions |
1417 | |
421406a4 |
1418 | \S{faq-openssh}{Question} Is PuTTY a port of \i{OpenSSH}, or based on |
928f5301 |
1419 | OpenSSH or OpenSSL? |
f9908cf7 |
1420 | |
1421 | No, it isn't. PuTTY is almost completely composed of code written |
1422 | from scratch for PuTTY. The only code we share with OpenSSH is the |
928f5301 |
1423 | detector for SSH-1 CRC compensation attacks, written by CORE SDI |
1424 | S.A; we share no code at all with OpenSSL. |
f9908cf7 |
1425 | |
606398fb |
1426 | \S{faq-sillyputty}{Question} Where can I buy silly putty? |
1427 | |
1428 | You're looking at the wrong web site; the only PuTTY we know about |
1429 | here is the name of a computer program. |
1430 | |
1431 | If you want the kind of putty you can buy as an executive toy, the |
1432 | PuTTY team can personally recommend Thinking Putty, which you can |
1433 | buy from Crazy Aaron's Putty World, at |
1434 | \W{http://www.puttyworld.com}\cw{www.puttyworld.com}. |
1435 | |
fa58cf81 |
1436 | \S{faq-meaning}{Question} What does \q{PuTTY} mean? |
ee46ef84 |
1437 | |
fa58cf81 |
1438 | It's the name of a popular SSH and Telnet client. Any other meaning |
1439 | is in the eye of the beholder. It's been rumoured that \q{PuTTY} |
1440 | is the antonym of \q{\cw{getty}}, or that it's the stuff that makes your |
1441 | Windows useful, or that it's a kind of plutonium Teletype. We |
1442 | couldn't possibly comment on such allegations. |
1443 | |
1444 | \S{faq-pronounce}{Question} How do I pronounce \q{PuTTY}? |
1445 | |
1446 | Exactly like the English word \q{putty}, which we pronounce |
65b15d17 |
1447 | /\u02C8{'}p\u028C{V}ti/. |