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588df31a | 1 | .\" -*- nroff -*- |
2 | .\" | |
3 | .\" Author: Tatu Ylonen <ylo@cs.hut.fi> | |
4 | .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland | |
5 | .\" All rights reserved | |
6 | .\" | |
7 | .\" As far as I am concerned, the code I have written for this software | |
8 | .\" can be used freely for any purpose. Any derived versions of this | |
9 | .\" software must be clearly marked as such, and if the derived work is | |
10 | .\" incompatible with the protocol description in the RFC file, it must be | |
11 | .\" called by a name other than "ssh" or "Secure Shell". | |
12 | .\" | |
13 | .\" Copyright (c) 1999,2000 Markus Friedl. All rights reserved. | |
14 | .\" Copyright (c) 1999 Aaron Campbell. All rights reserved. | |
15 | .\" Copyright (c) 1999 Theo de Raadt. All rights reserved. | |
16 | .\" | |
17 | .\" Redistribution and use in source and binary forms, with or without | |
18 | .\" modification, are permitted provided that the following conditions | |
19 | .\" are met: | |
20 | .\" 1. Redistributions of source code must retain the above copyright | |
21 | .\" notice, this list of conditions and the following disclaimer. | |
22 | .\" 2. Redistributions in binary form must reproduce the above copyright | |
23 | .\" notice, this list of conditions and the following disclaimer in the | |
24 | .\" documentation and/or other materials provided with the distribution. | |
25 | .\" | |
26 | .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR | |
27 | .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES | |
28 | .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. | |
29 | .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, | |
30 | .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | |
31 | .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
32 | .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
33 | .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
34 | .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF | |
35 | .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
36 | .\" | |
5adf6b9a | 37 | .\" $OpenBSD: ssh_config.5,v 1.115 2008/11/04 08:22:13 djm Exp $ |
e473dcd1 | 38 | .Dd $Mdocdate$ |
588df31a | 39 | .Dt SSH_CONFIG 5 |
40 | .Os | |
41 | .Sh NAME | |
42 | .Nm ssh_config | |
43 | .Nd OpenSSH SSH client configuration files | |
44 | .Sh SYNOPSIS | |
5792fbb7 | 45 | .Nm ~/.ssh/config |
46 | .Nm /etc/ssh/ssh_config | |
588df31a | 47 | .Sh DESCRIPTION |
c5786b30 | 48 | .Xr ssh 1 |
588df31a | 49 | obtains configuration data from the following sources in |
50 | the following order: | |
922f8f17 | 51 | .Pp |
4dcbbeea | 52 | .Bl -enum -offset indent -compact |
53 | .It | |
54 | command-line options | |
55 | .It | |
56 | user's configuration file | |
140e3e97 | 57 | .Pq Pa ~/.ssh/config |
4dcbbeea | 58 | .It |
59 | system-wide configuration file | |
60 | .Pq Pa /etc/ssh/ssh_config | |
61 | .El | |
588df31a | 62 | .Pp |
63 | For each parameter, the first obtained value | |
64 | will be used. | |
7034edae | 65 | The configuration files contain sections separated by |
588df31a | 66 | .Dq Host |
67 | specifications, and that section is only applied for hosts that | |
68 | match one of the patterns given in the specification. | |
69 | The matched host name is the one given on the command line. | |
70 | .Pp | |
71 | Since the first obtained value for each parameter is used, more | |
72 | host-specific declarations should be given near the beginning of the | |
73 | file, and general defaults at the end. | |
74 | .Pp | |
75 | The configuration file has the following format: | |
76 | .Pp | |
77 | Empty lines and lines starting with | |
78 | .Ql # | |
79 | are comments. | |
588df31a | 80 | Otherwise a line is of the format |
81 | .Dq keyword arguments . | |
82 | Configuration options may be separated by whitespace or | |
83 | optional whitespace and exactly one | |
84 | .Ql = ; | |
85 | the latter format is useful to avoid the need to quote whitespace | |
86 | when specifying configuration options using the | |
87 | .Nm ssh , | |
c04ba6a6 | 88 | .Nm scp , |
588df31a | 89 | and |
90 | .Nm sftp | |
91 | .Fl o | |
92 | option. | |
533b9133 | 93 | Arguments may optionally be enclosed in double quotes |
94 | .Pq \&" | |
95 | in order to represent arguments containing spaces. | |
588df31a | 96 | .Pp |
97 | The possible | |
98 | keywords and their meanings are as follows (note that | |
99 | keywords are case-insensitive and arguments are case-sensitive): | |
100 | .Bl -tag -width Ds | |
101 | .It Cm Host | |
102 | Restricts the following declarations (up to the next | |
103 | .Cm Host | |
104 | keyword) to be only for those hosts that match one of the patterns | |
105 | given after the keyword. | |
686bdcbd | 106 | If more than one pattern is provided, they should be separated by whitespace. |
588df31a | 107 | A single |
f09ffbdb | 108 | .Ql * |
588df31a | 109 | as a pattern can be used to provide global |
110 | defaults for all hosts. | |
111 | The host is the | |
112 | .Ar hostname | |
f09ffbdb | 113 | argument given on the command line (i.e. the name is not converted to |
588df31a | 114 | a canonicalized host name before matching). |
436a5ff9 | 115 | .Pp |
116 | See | |
117 | .Sx PATTERNS | |
118 | for more information on patterns. | |
f811e52a | 119 | .It Cm AddressFamily |
3cbc677d | 120 | Specifies which address family to use when connecting. |
121 | Valid arguments are | |
f811e52a | 122 | .Dq any , |
123 | .Dq inet | |
c5786b30 | 124 | (use IPv4 only), or |
f811e52a | 125 | .Dq inet6 |
0d6cbe2c | 126 | (use IPv6 only). |
588df31a | 127 | .It Cm BatchMode |
128 | If set to | |
129 | .Dq yes , | |
130 | passphrase/password querying will be disabled. | |
131 | This option is useful in scripts and other batch jobs where no user | |
132 | is present to supply the password. | |
133 | The argument must be | |
134 | .Dq yes | |
135 | or | |
136 | .Dq no . | |
137 | The default is | |
138 | .Dq no . | |
139 | .It Cm BindAddress | |
1a8521be | 140 | Use the specified address on the local machine as the source address of |
82b7531b | 141 | the connection. |
142 | Only useful on systems with more than one address. | |
588df31a | 143 | Note that this option does not work if |
144 | .Cm UsePrivilegedPort | |
145 | is set to | |
146 | .Dq yes . | |
147 | .It Cm ChallengeResponseAuthentication | |
340a4caf | 148 | Specifies whether to use challenge-response authentication. |
588df31a | 149 | The argument to this keyword must be |
150 | .Dq yes | |
151 | or | |
152 | .Dq no . | |
153 | The default is | |
154 | .Dq yes . | |
155 | .It Cm CheckHostIP | |
156 | If this flag is set to | |
157 | .Dq yes , | |
c5786b30 | 158 | .Xr ssh 1 |
159 | will additionally check the host IP address in the | |
588df31a | 160 | .Pa known_hosts |
161 | file. | |
162 | This allows ssh to detect if a host key changed due to DNS spoofing. | |
163 | If the option is set to | |
164 | .Dq no , | |
165 | the check will not be executed. | |
166 | The default is | |
167 | .Dq yes . | |
168 | .It Cm Cipher | |
169 | Specifies the cipher to use for encrypting the session | |
170 | in protocol version 1. | |
171 | Currently, | |
172 | .Dq blowfish , | |
173 | .Dq 3des , | |
174 | and | |
175 | .Dq des | |
176 | are supported. | |
177 | .Ar des | |
178 | is only supported in the | |
c5786b30 | 179 | .Xr ssh 1 |
588df31a | 180 | client for interoperability with legacy protocol 1 implementations |
181 | that do not support the | |
182 | .Ar 3des | |
a4e5acef | 183 | cipher. |
184 | Its use is strongly discouraged due to cryptographic weaknesses. | |
588df31a | 185 | The default is |
186 | .Dq 3des . | |
187 | .It Cm Ciphers | |
188 | Specifies the ciphers allowed for protocol version 2 | |
189 | in order of preference. | |
190 | Multiple ciphers must be comma-separated. | |
3b9baa7b | 191 | The supported ciphers are |
192 | .Dq 3des-cbc , | |
193 | .Dq aes128-cbc , | |
194 | .Dq aes192-cbc , | |
195 | .Dq aes256-cbc , | |
196 | .Dq aes128-ctr , | |
197 | .Dq aes192-ctr , | |
198 | .Dq aes256-ctr , | |
74a66cc8 | 199 | .Dq arcfour128 , |
200 | .Dq arcfour256 , | |
3b9baa7b | 201 | .Dq arcfour , |
202 | .Dq blowfish-cbc , | |
203 | and | |
204 | .Dq cast128-cbc . | |
c5786b30 | 205 | The default is: |
206 | .Bd -literal -offset 3n | |
207 | aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128, | |
208 | arcfour256,arcfour,aes192-cbc,aes256-cbc,aes128-ctr, | |
209 | aes192-ctr,aes256-ctr | |
588df31a | 210 | .Ed |
211 | .It Cm ClearAllForwardings | |
c5786b30 | 212 | Specifies that all local, remote, and dynamic port forwardings |
588df31a | 213 | specified in the configuration files or on the command line be |
a4e5acef | 214 | cleared. |
215 | This option is primarily useful when used from the | |
c5786b30 | 216 | .Xr ssh 1 |
588df31a | 217 | command line to clear port forwardings set in |
218 | configuration files, and is automatically set by | |
219 | .Xr scp 1 | |
220 | and | |
221 | .Xr sftp 1 . | |
222 | The argument must be | |
223 | .Dq yes | |
224 | or | |
225 | .Dq no . | |
226 | The default is | |
227 | .Dq no . | |
228 | .It Cm Compression | |
229 | Specifies whether to use compression. | |
230 | The argument must be | |
231 | .Dq yes | |
232 | or | |
233 | .Dq no . | |
234 | The default is | |
235 | .Dq no . | |
236 | .It Cm CompressionLevel | |
237 | Specifies the compression level to use if compression is enabled. | |
238 | The argument must be an integer from 1 (fast) to 9 (slow, best). | |
239 | The default level is 6, which is good for most applications. | |
240 | The meaning of the values is the same as in | |
241 | .Xr gzip 1 . | |
242 | Note that this option applies to protocol version 1 only. | |
243 | .It Cm ConnectionAttempts | |
244 | Specifies the number of tries (one per second) to make before exiting. | |
245 | The argument must be an integer. | |
246 | This may be useful in scripts if the connection sometimes fails. | |
247 | The default is 1. | |
09ab3296 | 248 | .It Cm ConnectTimeout |
c5786b30 | 249 | Specifies the timeout (in seconds) used when connecting to the |
250 | SSH server, instead of using the default system TCP timeout. | |
3cbc677d | 251 | This value is used only when the target is down or really unreachable, |
252 | not when it refuses the connection. | |
5e96b616 | 253 | .It Cm ControlMaster |
254 | Enables the sharing of multiple sessions over a single network connection. | |
255 | When set to | |
c5786b30 | 256 | .Dq yes , |
257 | .Xr ssh 1 | |
5e96b616 | 258 | will listen for connections on a control socket specified using the |
259 | .Cm ControlPath | |
260 | argument. | |
261 | Additional sessions can connect to this socket using the same | |
262 | .Cm ControlPath | |
263 | with | |
264 | .Cm ControlMaster | |
265 | set to | |
266 | .Dq no | |
9a5cfb58 | 267 | (the default). |
db98627d | 268 | These sessions will try to reuse the master instance's network connection |
6b0b0d65 | 269 | rather than initiating new ones, but will fall back to connecting normally |
270 | if the control socket does not exist, or is not listening. | |
271 | .Pp | |
0d34d6ce | 272 | Setting this to |
273 | .Dq ask | |
c5786b30 | 274 | will cause ssh |
0d34d6ce | 275 | to listen for control connections, but require confirmation using the |
276 | .Ev SSH_ASKPASS | |
277 | program before they are accepted (see | |
278 | .Xr ssh-add 1 | |
9a5cfb58 | 279 | for details). |
cc8ca1e6 | 280 | If the |
281 | .Cm ControlPath | |
c5786b30 | 282 | cannot be opened, |
283 | ssh will continue without connecting to a master instance. | |
9dfd96d6 | 284 | .Pp |
ef07103c | 285 | X11 and |
d313869b | 286 | .Xr ssh-agent 1 |
ef07103c | 287 | forwarding is supported over these multiplexed connections, however the |
8918b906 | 288 | display and agent forwarded will be the one belonging to the master |
d313869b | 289 | connection i.e. it is not possible to forward multiple displays or agents. |
ef07103c | 290 | .Pp |
9dfd96d6 | 291 | Two additional options allow for opportunistic multiplexing: try to use a |
292 | master connection but fall back to creating a new one if one does not already | |
293 | exist. | |
294 | These options are: | |
295 | .Dq auto | |
296 | and | |
297 | .Dq autoask . | |
298 | The latter requires confirmation like the | |
299 | .Dq ask | |
300 | option. | |
5e96b616 | 301 | .It Cm ControlPath |
a980cbd7 | 302 | Specify the path to the control socket used for connection sharing as described |
303 | in the | |
5e96b616 | 304 | .Cm ControlMaster |
699255b5 | 305 | section above or the string |
306 | .Dq none | |
307 | to disable connection sharing. | |
a980cbd7 | 308 | In the path, |
f7b8224d | 309 | .Ql %l |
310 | will be substituted by the local host name, | |
a980cbd7 | 311 | .Ql %h |
312 | will be substituted by the target host name, | |
313 | .Ql %p | |
c5786b30 | 314 | the port, and |
a980cbd7 | 315 | .Ql %r |
316 | by the remote login username. | |
9dfd96d6 | 317 | It is recommended that any |
318 | .Cm ControlPath | |
319 | used for opportunistic connection sharing include | |
5e7007ea | 320 | at least %h, %p, and %r. |
9dfd96d6 | 321 | This ensures that shared connections are uniquely identified. |
9a5cfb58 | 322 | .It Cm DynamicForward |
0b3950af | 323 | Specifies that a TCP port on the local machine be forwarded |
9a5cfb58 | 324 | over the secure channel, and the application |
325 | protocol is then used to determine where to connect to from the | |
326 | remote machine. | |
5ddc5eb4 | 327 | .Pp |
328 | The argument must be | |
329 | .Sm off | |
330 | .Oo Ar bind_address : Oc Ar port . | |
331 | .Sm on | |
332 | IPv6 addresses can be specified by enclosing addresses in square brackets or | |
333 | by using an alternative syntax: | |
334 | .Oo Ar bind_address Ns / Oc Ns Ar port . | |
335 | By default, the local port is bound in accordance with the | |
336 | .Cm GatewayPorts | |
337 | setting. | |
338 | However, an explicit | |
339 | .Ar bind_address | |
340 | may be used to bind the connection to a specific address. | |
341 | The | |
342 | .Ar bind_address | |
343 | of | |
344 | .Dq localhost | |
345 | indicates that the listening port be bound for local use only, while an | |
346 | empty address or | |
347 | .Sq * | |
348 | indicates that the port should be available from all interfaces. | |
349 | .Pp | |
9a5cfb58 | 350 | Currently the SOCKS4 and SOCKS5 protocols are supported, and |
c5786b30 | 351 | .Xr ssh 1 |
9a5cfb58 | 352 | will act as a SOCKS server. |
353 | Multiple forwardings may be specified, and | |
354 | additional forwardings can be given on the command line. | |
355 | Only the superuser can forward privileged ports. | |
f0677b69 | 356 | .It Cm EnableSSHKeysign |
357 | Setting this option to | |
358 | .Dq yes | |
359 | in the global client configuration file | |
360 | .Pa /etc/ssh/ssh_config | |
361 | enables the use of the helper program | |
362 | .Xr ssh-keysign 8 | |
363 | during | |
364 | .Cm HostbasedAuthentication . | |
365 | The argument must be | |
366 | .Dq yes | |
367 | or | |
368 | .Dq no . | |
369 | The default is | |
370 | .Dq no . | |
246bb171 | 371 | This option should be placed in the non-hostspecific section. |
f0677b69 | 372 | See |
373 | .Xr ssh-keysign 8 | |
374 | for more information. | |
588df31a | 375 | .It Cm EscapeChar |
376 | Sets the escape character (default: | |
377 | .Ql ~ ) . | |
378 | The escape character can also | |
379 | be set on the command line. | |
380 | The argument should be a single character, | |
381 | .Ql ^ | |
382 | followed by a letter, or | |
383 | .Dq none | |
384 | to disable the escape | |
385 | character entirely (making the connection transparent for binary | |
386 | data). | |
42ea6f5e | 387 | .It Cm ExitOnForwardFailure |
388 | Specifies whether | |
389 | .Xr ssh 1 | |
390 | should terminate the connection if it cannot set up all requested | |
1ce8114b | 391 | dynamic, tunnel, local, and remote port forwardings. |
42ea6f5e | 392 | The argument must be |
393 | .Dq yes | |
394 | or | |
395 | .Dq no . | |
396 | The default is | |
397 | .Dq no . | |
588df31a | 398 | .It Cm ForwardAgent |
399 | Specifies whether the connection to the authentication agent (if any) | |
400 | will be forwarded to the remote machine. | |
401 | The argument must be | |
402 | .Dq yes | |
403 | or | |
404 | .Dq no . | |
405 | The default is | |
406 | .Dq no . | |
dbcdea68 | 407 | .Pp |
a4e5acef | 408 | Agent forwarding should be enabled with caution. |
409 | Users with the ability to bypass file permissions on the remote host | |
410 | (for the agent's Unix-domain socket) | |
411 | can access the local agent through the forwarded connection. | |
412 | An attacker cannot obtain key material from the agent, | |
dbcdea68 | 413 | however they can perform operations on the keys that enable them to |
414 | authenticate using the identities loaded into the agent. | |
588df31a | 415 | .It Cm ForwardX11 |
416 | Specifies whether X11 connections will be automatically redirected | |
417 | over the secure channel and | |
418 | .Ev DISPLAY | |
419 | set. | |
420 | The argument must be | |
421 | .Dq yes | |
422 | or | |
423 | .Dq no . | |
424 | The default is | |
425 | .Dq no . | |
dbcdea68 | 426 | .Pp |
a4e5acef | 427 | X11 forwarding should be enabled with caution. |
428 | Users with the ability to bypass file permissions on the remote host | |
d73a67d7 | 429 | (for the user's X11 authorization database) |
a4e5acef | 430 | can access the local X11 display through the forwarded connection. |
d73a67d7 | 431 | An attacker may then be able to perform activities such as keystroke monitoring |
432 | if the | |
433 | .Cm ForwardX11Trusted | |
434 | option is also enabled. | |
435 | .It Cm ForwardX11Trusted | |
b2e90ab5 | 436 | If this option is set to |
c5786b30 | 437 | .Dq yes , |
438 | remote X11 clients will have full access to the original X11 display. | |
9a6b3b7a | 439 | .Pp |
d73a67d7 | 440 | If this option is set to |
c5786b30 | 441 | .Dq no , |
442 | remote X11 clients will be considered untrusted and prevented | |
d73a67d7 | 443 | from stealing or tampering with data belonging to trusted X11 |
444 | clients. | |
9a6b3b7a | 445 | Furthermore, the |
446 | .Xr xauth 1 | |
447 | token used for the session will be set to expire after 20 minutes. | |
448 | Remote clients will be refused access after this time. | |
d73a67d7 | 449 | .Pp |
450 | The default is | |
451 | .Dq no . | |
452 | .Pp | |
453 | See the X11 SECURITY extension specification for full details on | |
454 | the restrictions imposed on untrusted clients. | |
588df31a | 455 | .It Cm GatewayPorts |
456 | Specifies whether remote hosts are allowed to connect to local | |
457 | forwarded ports. | |
458 | By default, | |
c5786b30 | 459 | .Xr ssh 1 |
a4e5acef | 460 | binds local port forwardings to the loopback address. |
461 | This prevents other remote hosts from connecting to forwarded ports. | |
588df31a | 462 | .Cm GatewayPorts |
c5786b30 | 463 | can be used to specify that ssh |
588df31a | 464 | should bind local port forwardings to the wildcard address, |
465 | thus allowing remote hosts to connect to forwarded ports. | |
466 | The argument must be | |
467 | .Dq yes | |
468 | or | |
469 | .Dq no . | |
470 | The default is | |
471 | .Dq no . | |
472 | .It Cm GlobalKnownHostsFile | |
473 | Specifies a file to use for the global | |
474 | host key database instead of | |
475 | .Pa /etc/ssh/ssh_known_hosts . | |
7364bd04 | 476 | .It Cm GSSAPIAuthentication |
e8dd24a8 | 477 | Specifies whether user authentication based on GSSAPI is allowed. |
d0445371 | 478 | The default is |
2ecb78df | 479 | .Dq no . |
7364bd04 | 480 | Note that this option applies to protocol version 2 only. |
481 | .It Cm GSSAPIDelegateCredentials | |
482 | Forward (delegate) credentials to the server. | |
483 | The default is | |
484 | .Dq no . | |
485 | Note that this option applies to protocol version 2 only. | |
5c63c2ab | 486 | .It Cm HashKnownHosts |
487 | Indicates that | |
c5786b30 | 488 | .Xr ssh 1 |
5c63c2ab | 489 | should hash host names and addresses when they are added to |
140e3e97 | 490 | .Pa ~/.ssh/known_hosts . |
5c63c2ab | 491 | These hashed names may be used normally by |
c5786b30 | 492 | .Xr ssh 1 |
5c63c2ab | 493 | and |
c5786b30 | 494 | .Xr sshd 8 , |
5c63c2ab | 495 | but they do not reveal identifying information should the file's contents |
496 | be disclosed. | |
497 | The default is | |
498 | .Dq no . | |
f0817fbb | 499 | Note that existing names and addresses in known hosts files |
500 | will not be converted automatically, | |
501 | but may be manually hashed using | |
bdffbcdc | 502 | .Xr ssh-keygen 1 . |
588df31a | 503 | .It Cm HostbasedAuthentication |
504 | Specifies whether to try rhosts based authentication with public key | |
505 | authentication. | |
506 | The argument must be | |
507 | .Dq yes | |
508 | or | |
509 | .Dq no . | |
510 | The default is | |
511 | .Dq no . | |
512 | This option applies to protocol version 2 only and | |
513 | is similar to | |
514 | .Cm RhostsRSAAuthentication . | |
515 | .It Cm HostKeyAlgorithms | |
516 | Specifies the protocol version 2 host key algorithms | |
517 | that the client wants to use in order of preference. | |
518 | The default for this option is: | |
519 | .Dq ssh-rsa,ssh-dss . | |
520 | .It Cm HostKeyAlias | |
521 | Specifies an alias that should be used instead of the | |
522 | real host name when looking up or saving the host key | |
523 | in the host key database files. | |
c5786b30 | 524 | This option is useful for tunneling SSH connections |
588df31a | 525 | or for multiple servers running on a single host. |
526 | .It Cm HostName | |
527 | Specifies the real host name to log into. | |
528 | This can be used to specify nicknames or abbreviations for hosts. | |
c5786b30 | 529 | The default is the name given on the command line. |
588df31a | 530 | Numeric IP addresses are also permitted (both on the command line and in |
531 | .Cm HostName | |
532 | specifications). | |
3a065ed0 | 533 | .It Cm IdentitiesOnly |
534 | Specifies that | |
c5786b30 | 535 | .Xr ssh 1 |
3a065ed0 | 536 | should only use the authentication identity files configured in the |
1e9b1b82 | 537 | .Nm |
3a065ed0 | 538 | files, |
c5786b30 | 539 | even if |
540 | .Xr ssh-agent 1 | |
3a065ed0 | 541 | offers more identities. |
542 | The argument to this keyword must be | |
543 | .Dq yes | |
544 | or | |
545 | .Dq no . | |
c5786b30 | 546 | This option is intended for situations where ssh-agent |
3a065ed0 | 547 | offers many different identities. |
548 | The default is | |
549 | .Dq no . | |
030723f9 | 550 | .It Cm IdentityFile |
551 | Specifies a file from which the user's RSA or DSA authentication identity | |
552 | is read. | |
553 | The default is | |
554 | .Pa ~/.ssh/identity | |
555 | for protocol version 1, and | |
556 | .Pa ~/.ssh/id_rsa | |
557 | and | |
558 | .Pa ~/.ssh/id_dsa | |
559 | for protocol version 2. | |
560 | Additionally, any identities represented by the authentication agent | |
561 | will be used for authentication. | |
8cffe22a | 562 | .Pp |
030723f9 | 563 | The file name may use the tilde |
99d18e3e | 564 | syntax to refer to a user's home directory or one of the following |
8cffe22a | 565 | escape characters: |
566 | .Ql %d | |
567 | (local user's home directory), | |
568 | .Ql %u | |
569 | (local user name), | |
570 | .Ql %l | |
571 | (local host name), | |
572 | .Ql %h | |
573 | (remote host name) or | |
b4d7dedd | 574 | .Ql %r |
8cffe22a | 575 | (remote user name). |
576 | .Pp | |
030723f9 | 577 | It is possible to have |
578 | multiple identity files specified in configuration files; all these | |
579 | identities will be tried in sequence. | |
530c2ec0 | 580 | .It Cm KbdInteractiveAuthentication |
581 | Specifies whether to use keyboard-interactive authentication. | |
582 | The argument to this keyword must be | |
583 | .Dq yes | |
584 | or | |
585 | .Dq no . | |
586 | The default is | |
587 | .Dq yes . | |
396070f8 | 588 | .It Cm KbdInteractiveDevices |
589 | Specifies the list of methods to use in keyboard-interactive authentication. | |
590 | Multiple method names must be comma-separated. | |
591 | The default is to use the server specified list. | |
2963b207 | 592 | The methods available vary depending on what the server supports. |
593 | For an OpenSSH server, | |
594 | it may be zero or more of: | |
595 | .Dq bsdauth , | |
596 | .Dq pam , | |
597 | and | |
598 | .Dq skey . | |
d20f3c9e | 599 | .It Cm LocalCommand |
600 | Specifies a command to execute on the local machine after successfully | |
601 | connecting to the server. | |
602 | The command string extends to the end of the line, and is executed with | |
eb86ca9d | 603 | the user's shell. |
e9d0b573 | 604 | The following escape character substitutions will be performed: |
605 | .Ql %d | |
606 | (local user's home directory), | |
607 | .Ql %h | |
608 | (remote host name), | |
609 | .Ql %l | |
610 | (local host name), | |
611 | .Ql %n | |
612 | (host name as provided on the command line), | |
613 | .Ql %p | |
614 | (remote port), | |
615 | .Ql %r | |
616 | (remote user name) or | |
617 | .Ql %u | |
618 | (local user name). | |
d20f3c9e | 619 | This directive is ignored unless |
620 | .Cm PermitLocalCommand | |
621 | has been enabled. | |
588df31a | 622 | .It Cm LocalForward |
0b3950af | 623 | Specifies that a TCP port on the local machine be forwarded over |
588df31a | 624 | the secure channel to the specified host and port from the remote machine. |
ecda4ffb | 625 | The first argument must be |
3867aa0a | 626 | .Sm off |
ecda4ffb | 627 | .Oo Ar bind_address : Oc Ar port |
3867aa0a | 628 | .Sm on |
ecda4ffb | 629 | and the second argument must be |
630 | .Ar host : Ns Ar hostport . | |
cd8f998c | 631 | IPv6 addresses can be specified by enclosing addresses in square brackets or |
3867aa0a | 632 | by using an alternative syntax: |
ecda4ffb | 633 | .Oo Ar bind_address Ns / Oc Ns Ar port |
634 | and | |
635 | .Ar host Ns / Ns Ar hostport . | |
cd8f998c | 636 | Multiple forwardings may be specified, and additional forwardings can be |
3867aa0a | 637 | given on the command line. |
588df31a | 638 | Only the superuser can forward privileged ports. |
3867aa0a | 639 | By default, the local port is bound in accordance with the |
640 | .Cm GatewayPorts | |
641 | setting. | |
642 | However, an explicit | |
643 | .Ar bind_address | |
644 | may be used to bind the connection to a specific address. | |
645 | The | |
646 | .Ar bind_address | |
647 | of | |
648 | .Dq localhost | |
cd8f998c | 649 | indicates that the listening port be bound for local use only, while an |
650 | empty address or | |
651 | .Sq * | |
3867aa0a | 652 | indicates that the port should be available from all interfaces. |
588df31a | 653 | .It Cm LogLevel |
654 | Gives the verbosity level that is used when logging messages from | |
c5786b30 | 655 | .Xr ssh 1 . |
588df31a | 656 | The possible values are: |
c5786b30 | 657 | QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. |
a4e5acef | 658 | The default is INFO. |
659 | DEBUG and DEBUG1 are equivalent. | |
660 | DEBUG2 and DEBUG3 each specify higher levels of verbose output. | |
588df31a | 661 | .It Cm MACs |
662 | Specifies the MAC (message authentication code) algorithms | |
663 | in order of preference. | |
664 | The MAC algorithm is used in protocol version 2 | |
665 | for data integrity protection. | |
666 | Multiple algorithms must be comma-separated. | |
c5786b30 | 667 | The default is: |
bbc77085 | 668 | .Bd -literal -offset indent |
669 | hmac-md5,hmac-sha1,umac-64@openssh.com, | |
670 | hmac-ripemd160,hmac-sha1-96,hmac-md5-96 | |
671 | .Ed | |
588df31a | 672 | .It Cm NoHostAuthenticationForLocalhost |
673 | This option can be used if the home directory is shared across machines. | |
674 | In this case localhost will refer to a different machine on each of | |
675 | the machines and the user will get many warnings about changed host keys. | |
676 | However, this option disables host authentication for localhost. | |
677 | The argument to this keyword must be | |
678 | .Dq yes | |
679 | or | |
680 | .Dq no . | |
681 | The default is to check the host key for localhost. | |
682 | .It Cm NumberOfPasswordPrompts | |
683 | Specifies the number of password prompts before giving up. | |
684 | The argument to this keyword must be an integer. | |
c5786b30 | 685 | The default is 3. |
588df31a | 686 | .It Cm PasswordAuthentication |
687 | Specifies whether to use password authentication. | |
688 | The argument to this keyword must be | |
689 | .Dq yes | |
690 | or | |
691 | .Dq no . | |
692 | The default is | |
693 | .Dq yes . | |
d20f3c9e | 694 | .It Cm PermitLocalCommand |
695 | Allow local command execution via the | |
696 | .Ic LocalCommand | |
697 | option or using the | |
64925c6d | 698 | .Ic !\& Ns Ar command |
d20f3c9e | 699 | escape sequence in |
700 | .Xr ssh 1 . | |
701 | The argument must be | |
702 | .Dq yes | |
703 | or | |
704 | .Dq no . | |
705 | The default is | |
706 | .Dq no . | |
030723f9 | 707 | .It Cm Port |
708 | Specifies the port number to connect on the remote host. | |
c5786b30 | 709 | The default is 22. |
588df31a | 710 | .It Cm PreferredAuthentications |
711 | Specifies the order in which the client should try protocol 2 | |
3cbc677d | 712 | authentication methods. |
4e5038f7 | 713 | This allows a client to prefer one method (e.g.\& |
588df31a | 714 | .Cm keyboard-interactive ) |
4e5038f7 | 715 | over another method (e.g.\& |
588df31a | 716 | .Cm password ) |
717 | The default for this option is: | |
f127d8a4 | 718 | .Do gssapi-with-mic , |
719 | hostbased, | |
720 | publickey, | |
721 | keyboard-interactive, | |
722 | password | |
723 | .Dc . | |
588df31a | 724 | .It Cm Protocol |
725 | Specifies the protocol versions | |
c5786b30 | 726 | .Xr ssh 1 |
588df31a | 727 | should support in order of preference. |
728 | The possible values are | |
c5786b30 | 729 | .Sq 1 |
588df31a | 730 | and |
c5786b30 | 731 | .Sq 2 . |
588df31a | 732 | Multiple versions must be comma-separated. |
733 | The default is | |
734 | .Dq 2,1 . | |
c5786b30 | 735 | This means that ssh |
588df31a | 736 | tries version 2 and falls back to version 1 |
737 | if version 2 is not available. | |
738 | .It Cm ProxyCommand | |
739 | Specifies the command to use to connect to the server. | |
740 | The command | |
741 | string extends to the end of the line, and is executed with | |
eb86ca9d | 742 | the user's shell. |
588df31a | 743 | In the command string, |
744 | .Ql %h | |
745 | will be substituted by the host name to | |
746 | connect and | |
747 | .Ql %p | |
748 | by the port. | |
749 | The command can be basically anything, | |
750 | and should read from its standard input and write to its standard output. | |
751 | It should eventually connect an | |
752 | .Xr sshd 8 | |
753 | server running on some machine, or execute | |
754 | .Ic sshd -i | |
755 | somewhere. | |
756 | Host key management will be done using the | |
757 | HostName of the host being connected (defaulting to the name typed by | |
758 | the user). | |
a4e5acef | 759 | Setting the command to |
760 | .Dq none | |
f78bde70 | 761 | disables this option entirely. |
588df31a | 762 | Note that |
763 | .Cm CheckHostIP | |
764 | is not available for connects with a proxy command. | |
765 | .Pp | |
2b610872 | 766 | This directive is useful in conjunction with |
767 | .Xr nc 1 | |
768 | and its proxy support. | |
9fa42d41 | 769 | For example, the following directive would connect via an HTTP proxy at |
2b610872 | 770 | 192.0.2.0: |
771 | .Bd -literal -offset 3n | |
772 | ProxyCommand /usr/bin/nc -X connect -x 192.0.2.0:8080 %h %p | |
773 | .Ed | |
588df31a | 774 | .It Cm PubkeyAuthentication |
775 | Specifies whether to try public key authentication. | |
776 | The argument to this keyword must be | |
777 | .Dq yes | |
778 | or | |
779 | .Dq no . | |
780 | The default is | |
781 | .Dq yes . | |
782 | This option applies to protocol version 2 only. | |
db175906 | 783 | .It Cm RekeyLimit |
784 | Specifies the maximum amount of data that may be transmitted before the | |
0ce89457 | 785 | session key is renegotiated. |
db175906 | 786 | The argument is the number of bytes, with an optional suffix of |
0ce89457 | 787 | .Sq K , |
788 | .Sq M , | |
db175906 | 789 | or |
0ce89457 | 790 | .Sq G |
db175906 | 791 | to indicate Kilobytes, Megabytes, or Gigabytes, respectively. |
792 | The default is between | |
c5786b30 | 793 | .Sq 1G |
db175906 | 794 | and |
c5786b30 | 795 | .Sq 4G , |
db175906 | 796 | depending on the cipher. |
0ce89457 | 797 | This option applies to protocol version 2 only. |
588df31a | 798 | .It Cm RemoteForward |
0b3950af | 799 | Specifies that a TCP port on the remote machine be forwarded over |
588df31a | 800 | the secure channel to the specified host and port from the local machine. |
ecda4ffb | 801 | The first argument must be |
3867aa0a | 802 | .Sm off |
ecda4ffb | 803 | .Oo Ar bind_address : Oc Ar port |
6d7a9e8f | 804 | .Sm on |
ecda4ffb | 805 | and the second argument must be |
806 | .Ar host : Ns Ar hostport . | |
807 | IPv6 addresses can be specified by enclosing addresses in square brackets | |
808 | or by using an alternative syntax: | |
809 | .Oo Ar bind_address Ns / Oc Ns Ar port | |
810 | and | |
811 | .Ar host Ns / Ns Ar hostport . | |
588df31a | 812 | Multiple forwardings may be specified, and additional |
813 | forwardings can be given on the command line. | |
5769ea87 | 814 | Privileged ports can be forwarded only when |
815 | logging in as root on the remote machine. | |
3867aa0a | 816 | .Pp |
817 | If the | |
818 | .Ar bind_address | |
819 | is not specified, the default is to only bind to loopback addresses. | |
820 | If the | |
821 | .Ar bind_address | |
822 | is | |
823 | .Ql * | |
824 | or an empty string, then the forwarding is requested to listen on all | |
825 | interfaces. | |
826 | Specifying a remote | |
827 | .Ar bind_address | |
cd8f998c | 828 | will only succeed if the server's |
829 | .Cm GatewayPorts | |
3867aa0a | 830 | option is enabled (see |
cd8f998c | 831 | .Xr sshd_config 5 ) . |
588df31a | 832 | .It Cm RhostsRSAAuthentication |
833 | Specifies whether to try rhosts based authentication with RSA host | |
834 | authentication. | |
835 | The argument must be | |
836 | .Dq yes | |
837 | or | |
838 | .Dq no . | |
839 | The default is | |
840 | .Dq no . | |
841 | This option applies to protocol version 1 only and requires | |
c5786b30 | 842 | .Xr ssh 1 |
588df31a | 843 | to be setuid root. |
844 | .It Cm RSAAuthentication | |
845 | Specifies whether to try RSA authentication. | |
846 | The argument to this keyword must be | |
847 | .Dq yes | |
848 | or | |
849 | .Dq no . | |
850 | RSA authentication will only be | |
851 | attempted if the identity file exists, or an authentication agent is | |
852 | running. | |
853 | The default is | |
854 | .Dq yes . | |
855 | Note that this option applies to protocol version 1 only. | |
61a2c1da | 856 | .It Cm SendEnv |
857 | Specifies what variables from the local | |
858 | .Xr environ 7 | |
859 | should be sent to the server. | |
c5786b30 | 860 | Note that environment passing is only supported for protocol 2. |
861 | The server must also support it, and the server must be configured to | |
b8b9f2e6 | 862 | accept these environment variables. |
61a2c1da | 863 | Refer to |
864 | .Cm AcceptEnv | |
865 | in | |
866 | .Xr sshd_config 5 | |
867 | for how to configure the server. | |
95d46d8f | 868 | Variables are specified by name, which may contain wildcard characters. |
b8b9f2e6 | 869 | Multiple environment variables may be separated by whitespace or spread |
61a2c1da | 870 | across multiple |
871 | .Cm SendEnv | |
872 | directives. | |
873 | The default is not to send any environment variables. | |
436a5ff9 | 874 | .Pp |
875 | See | |
876 | .Sx PATTERNS | |
877 | for more information on patterns. | |
5d8d32a3 | 878 | .It Cm ServerAliveCountMax |
79e46360 | 879 | Sets the number of server alive messages (see below) which may be |
5d8d32a3 | 880 | sent without |
c5786b30 | 881 | .Xr ssh 1 |
5d8d32a3 | 882 | receiving any messages back from the server. |
883 | If this threshold is reached while server alive messages are being sent, | |
c5786b30 | 884 | ssh will disconnect from the server, terminating the session. |
5d8d32a3 | 885 | It is important to note that the use of server alive messages is very |
886 | different from | |
887 | .Cm TCPKeepAlive | |
888 | (below). | |
889 | The server alive messages are sent through the encrypted channel | |
890 | and therefore will not be spoofable. | |
891 | The TCP keepalive option enabled by | |
892 | .Cm TCPKeepAlive | |
893 | is spoofable. | |
894 | The server alive mechanism is valuable when the client or | |
895 | server depend on knowing when a connection has become inactive. | |
896 | .Pp | |
897 | The default value is 3. | |
898 | If, for example, | |
899 | .Cm ServerAliveInterval | |
c5786b30 | 900 | (see below) is set to 15 and |
5d8d32a3 | 901 | .Cm ServerAliveCountMax |
c5786b30 | 902 | is left at the default, if the server becomes unresponsive, |
903 | ssh will disconnect after approximately 45 seconds. | |
2d762582 | 904 | This option applies to protocol version 2 only. |
030723f9 | 905 | .It Cm ServerAliveInterval |
906 | Sets a timeout interval in seconds after which if no data has been received | |
907 | from the server, | |
c5786b30 | 908 | .Xr ssh 1 |
030723f9 | 909 | will send a message through the encrypted |
910 | channel to request a response from the server. | |
911 | The default | |
912 | is 0, indicating that these messages will not be sent to the server. | |
913 | This option applies to protocol version 2 only. | |
588df31a | 914 | .It Cm SmartcardDevice |
3cbc677d | 915 | Specifies which smartcard device to use. |
916 | The argument to this keyword is the device | |
c5786b30 | 917 | .Xr ssh 1 |
588df31a | 918 | should use to communicate with a smartcard used for storing the user's |
3cbc677d | 919 | private RSA key. |
920 | By default, no device is specified and smartcard support is not activated. | |
588df31a | 921 | .It Cm StrictHostKeyChecking |
922 | If this flag is set to | |
923 | .Dq yes , | |
c5786b30 | 924 | .Xr ssh 1 |
588df31a | 925 | will never automatically add host keys to the |
140e3e97 | 926 | .Pa ~/.ssh/known_hosts |
588df31a | 927 | file, and refuses to connect to hosts whose host key has changed. |
928 | This provides maximum protection against trojan horse attacks, | |
c5786b30 | 929 | though it can be annoying when the |
588df31a | 930 | .Pa /etc/ssh/ssh_known_hosts |
c5786b30 | 931 | file is poorly maintained or when connections to new hosts are |
588df31a | 932 | frequently made. |
933 | This option forces the user to manually | |
934 | add all new hosts. | |
935 | If this flag is set to | |
936 | .Dq no , | |
c5786b30 | 937 | ssh will automatically add new host keys to the |
588df31a | 938 | user known hosts files. |
939 | If this flag is set to | |
940 | .Dq ask , | |
941 | new host keys | |
942 | will be added to the user known host files only after the user | |
943 | has confirmed that is what they really want to do, and | |
c5786b30 | 944 | ssh will refuse to connect to hosts whose host key has changed. |
588df31a | 945 | The host keys of |
946 | known hosts will be verified automatically in all cases. | |
947 | The argument must be | |
948 | .Dq yes , | |
c5786b30 | 949 | .Dq no , |
588df31a | 950 | or |
951 | .Dq ask . | |
952 | The default is | |
953 | .Dq ask . | |
fd573618 | 954 | .It Cm TCPKeepAlive |
955 | Specifies whether the system should send TCP keepalive messages to the | |
956 | other side. | |
957 | If they are sent, death of the connection or crash of one | |
958 | of the machines will be properly noticed. | |
959 | However, this means that | |
960 | connections will die if the route is down temporarily, and some people | |
961 | find it annoying. | |
962 | .Pp | |
963 | The default is | |
964 | .Dq yes | |
965 | (to send TCP keepalive messages), and the client will notice | |
966 | if the network goes down or the remote host dies. | |
967 | This is important in scripts, and many users want it too. | |
968 | .Pp | |
969 | To disable TCP keepalive messages, the value should be set to | |
970 | .Dq no . | |
d20f3c9e | 971 | .It Cm Tunnel |
06fa4ac1 | 972 | Request |
d20f3c9e | 973 | .Xr tun 4 |
a274ba38 | 974 | device forwarding between the client and the server. |
d20f3c9e | 975 | The argument must be |
a4f24bf8 | 976 | .Dq yes , |
06fa4ac1 | 977 | .Dq point-to-point |
978 | (layer 3), | |
979 | .Dq ethernet | |
980 | (layer 2), | |
d20f3c9e | 981 | or |
982 | .Dq no . | |
06fa4ac1 | 983 | Specifying |
984 | .Dq yes | |
985 | requests the default tunnel mode, which is | |
986 | .Dq point-to-point . | |
d20f3c9e | 987 | The default is |
988 | .Dq no . | |
989 | .It Cm TunnelDevice | |
06fa4ac1 | 990 | Specifies the |
d20f3c9e | 991 | .Xr tun 4 |
06fa4ac1 | 992 | devices to open on the client |
993 | .Pq Ar local_tun | |
994 | and the server | |
995 | .Pq Ar remote_tun . | |
996 | .Pp | |
997 | The argument must be | |
998 | .Sm off | |
999 | .Ar local_tun Op : Ar remote_tun . | |
1000 | .Sm on | |
1001 | The devices may be specified by numerical ID or the keyword | |
1002 | .Dq any , | |
1003 | which uses the next available tunnel device. | |
1004 | If | |
1005 | .Ar remote_tun | |
1006 | is not specified, it defaults to | |
1007 | .Dq any . | |
1008 | The default is | |
1009 | .Dq any:any . | |
0c9851b1 | 1010 | .It Cm UsePrivilegedPort |
1011 | Specifies whether to use a privileged port for outgoing connections. | |
1012 | The argument must be | |
1013 | .Dq yes | |
1014 | or | |
1015 | .Dq no . | |
1016 | The default is | |
1017 | .Dq no . | |
1018 | If set to | |
c5786b30 | 1019 | .Dq yes , |
1020 | .Xr ssh 1 | |
0c9851b1 | 1021 | must be setuid root. |
1022 | Note that this option must be set to | |
1023 | .Dq yes | |
1024 | for | |
1025 | .Cm RhostsRSAAuthentication | |
1026 | with older servers. | |
588df31a | 1027 | .It Cm User |
1028 | Specifies the user to log in as. | |
1029 | This can be useful when a different user name is used on different machines. | |
1030 | This saves the trouble of | |
1031 | having to remember to give the user name on the command line. | |
1032 | .It Cm UserKnownHostsFile | |
1033 | Specifies a file to use for the user | |
1034 | host key database instead of | |
140e3e97 | 1035 | .Pa ~/.ssh/known_hosts . |
21289cd0 | 1036 | .It Cm VerifyHostKeyDNS |
1037 | Specifies whether to verify the remote key using DNS and SSHFP resource | |
1038 | records. | |
0161a13d | 1039 | If this option is set to |
1040 | .Dq yes , | |
dd376e92 | 1041 | the client will implicitly trust keys that match a secure fingerprint |
0161a13d | 1042 | from DNS. |
1043 | Insecure fingerprints will be handled as if this option was set to | |
1044 | .Dq ask . | |
1045 | If this option is set to | |
1046 | .Dq ask , | |
1047 | information on fingerprint match will be displayed, but the user will still | |
1048 | need to confirm new host keys according to the | |
1049 | .Cm StrictHostKeyChecking | |
1050 | option. | |
1051 | The argument must be | |
1052 | .Dq yes , | |
c5786b30 | 1053 | .Dq no , |
dd376e92 | 1054 | or |
1055 | .Dq ask . | |
21289cd0 | 1056 | The default is |
1057 | .Dq no . | |
0f92946c | 1058 | Note that this option applies to protocol version 2 only. |
c5786b30 | 1059 | .Pp |
1060 | See also | |
1061 | .Sx VERIFYING HOST KEYS | |
1062 | in | |
1063 | .Xr ssh 1 . | |
7b3999b8 | 1064 | .It Cm VisualHostKey |
1065 | If this flag is set to | |
1066 | .Dq yes , | |
1067 | an ASCII art representation of the remote host key fingerprint is | |
8d20b087 | 1068 | printed in addition to the hex fingerprint string at login and |
1069 | for unknown host keys. | |
7b3999b8 | 1070 | If this flag is set to |
1071 | .Dq no , | |
8d20b087 | 1072 | no fingerprint strings are printed at login and |
1073 | only the hex fingerprint string will be printed for unknown host keys. | |
7b3999b8 | 1074 | The default is |
1075 | .Dq no . | |
588df31a | 1076 | .It Cm XAuthLocation |
57ff5eeb | 1077 | Specifies the full pathname of the |
588df31a | 1078 | .Xr xauth 1 |
1079 | program. | |
1080 | The default is | |
1081 | .Pa /usr/X11R6/bin/xauth . | |
5adf6b9a | 1082 | .It Cm ZeroKnowledgePasswordAuthentication |
1083 | Specifies whether to use zero knowledge password authentication. | |
1084 | This authentication method avoids exposure of password to untrusted | |
1085 | hosts. | |
1086 | The argument to this keyword must be | |
1087 | .Dq yes | |
1088 | or | |
1089 | .Dq no . | |
1090 | The default is currently | |
1091 | .Dq no | |
1092 | as this method is considered experimental. | |
588df31a | 1093 | .El |
de4f5093 | 1094 | .Sh PATTERNS |
1095 | A | |
1096 | .Em pattern | |
1097 | consists of zero or more non-whitespace characters, | |
1098 | .Sq * | |
1099 | (a wildcard that matches zero or more characters), | |
1100 | or | |
1101 | .Sq ?\& | |
1102 | (a wildcard that matches exactly one character). | |
1103 | For example, to specify a set of declarations for any host in the | |
1104 | .Dq .co.uk | |
1105 | set of domains, | |
1106 | the following pattern could be used: | |
1107 | .Pp | |
1108 | .Dl Host *.co.uk | |
1109 | .Pp | |
1110 | The following pattern | |
1111 | would match any host in the 192.168.0.[0-9] network range: | |
1112 | .Pp | |
1113 | .Dl Host 192.168.0.? | |
1114 | .Pp | |
1115 | A | |
1116 | .Em pattern-list | |
1117 | is a comma-separated list of patterns. | |
1118 | Patterns within pattern-lists may be negated | |
1119 | by preceding them with an exclamation mark | |
1120 | .Pq Sq !\& . | |
1121 | For example, | |
1122 | to allow a key to be used from anywhere within an organisation | |
1123 | except from the | |
1124 | .Dq dialup | |
1125 | pool, | |
1126 | the following entry (in authorized_keys) could be used: | |
1127 | .Pp | |
1128 | .Dl from=\&"!*.dialup.example.com,*.example.com\&" | |
588df31a | 1129 | .Sh FILES |
1130 | .Bl -tag -width Ds | |
140e3e97 | 1131 | .It Pa ~/.ssh/config |
588df31a | 1132 | This is the per-user configuration file. |
1133 | The format of this file is described above. | |
c5786b30 | 1134 | This file is used by the SSH client. |
e1520719 | 1135 | Because of the potential for abuse, this file must have strict permissions: |
1136 | read/write for the user, and not accessible by others. | |
588df31a | 1137 | .It Pa /etc/ssh/ssh_config |
1138 | Systemwide configuration file. | |
1139 | This file provides defaults for those | |
1140 | values that are not specified in the user's configuration file, and | |
1141 | for those users who do not have a configuration file. | |
1142 | This file must be world-readable. | |
1143 | .El | |
be193d89 | 1144 | .Sh SEE ALSO |
1145 | .Xr ssh 1 | |
588df31a | 1146 | .Sh AUTHORS |
1147 | OpenSSH is a derivative of the original and free | |
1148 | ssh 1.2.12 release by Tatu Ylonen. | |
1149 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, | |
1150 | Theo de Raadt and Dug Song | |
1151 | removed many bugs, re-added newer features and | |
1152 | created OpenSSH. | |
1153 | Markus Friedl contributed the support for SSH | |
1154 | protocol versions 1.5 and 2.0. |