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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 | .\" | |
a64f8307 | 37 | .\" $OpenBSD: ssh_config.5,v 1.110 2008/06/12 19:10:09 jmc 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. | |
f6748d7b | 106 | If more than one pattern is provided, they should be separated by whitepsace. |
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 | |
aff73c5f | 164 | .Dq fingerprint , |
a64f8307 | 165 | a fingerprint and an ASCII art representation of the key are printed, |
166 | in addition to the host IP address check. | |
aff73c5f | 167 | If the option is set to |
588df31a | 168 | .Dq no , |
169 | the check will not be executed. | |
170 | The default is | |
171 | .Dq yes . | |
172 | .It Cm Cipher | |
173 | Specifies the cipher to use for encrypting the session | |
174 | in protocol version 1. | |
175 | Currently, | |
176 | .Dq blowfish , | |
177 | .Dq 3des , | |
178 | and | |
179 | .Dq des | |
180 | are supported. | |
181 | .Ar des | |
182 | is only supported in the | |
c5786b30 | 183 | .Xr ssh 1 |
588df31a | 184 | client for interoperability with legacy protocol 1 implementations |
185 | that do not support the | |
186 | .Ar 3des | |
a4e5acef | 187 | cipher. |
188 | Its use is strongly discouraged due to cryptographic weaknesses. | |
588df31a | 189 | The default is |
190 | .Dq 3des . | |
191 | .It Cm Ciphers | |
192 | Specifies the ciphers allowed for protocol version 2 | |
193 | in order of preference. | |
194 | Multiple ciphers must be comma-separated. | |
3b9baa7b | 195 | The supported ciphers are |
196 | .Dq 3des-cbc , | |
197 | .Dq aes128-cbc , | |
198 | .Dq aes192-cbc , | |
199 | .Dq aes256-cbc , | |
200 | .Dq aes128-ctr , | |
201 | .Dq aes192-ctr , | |
202 | .Dq aes256-ctr , | |
74a66cc8 | 203 | .Dq arcfour128 , |
204 | .Dq arcfour256 , | |
3b9baa7b | 205 | .Dq arcfour , |
206 | .Dq blowfish-cbc , | |
207 | and | |
208 | .Dq cast128-cbc . | |
c5786b30 | 209 | The default is: |
210 | .Bd -literal -offset 3n | |
211 | aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128, | |
212 | arcfour256,arcfour,aes192-cbc,aes256-cbc,aes128-ctr, | |
213 | aes192-ctr,aes256-ctr | |
588df31a | 214 | .Ed |
215 | .It Cm ClearAllForwardings | |
c5786b30 | 216 | Specifies that all local, remote, and dynamic port forwardings |
588df31a | 217 | specified in the configuration files or on the command line be |
a4e5acef | 218 | cleared. |
219 | This option is primarily useful when used from the | |
c5786b30 | 220 | .Xr ssh 1 |
588df31a | 221 | command line to clear port forwardings set in |
222 | configuration files, and is automatically set by | |
223 | .Xr scp 1 | |
224 | and | |
225 | .Xr sftp 1 . | |
226 | The argument must be | |
227 | .Dq yes | |
228 | or | |
229 | .Dq no . | |
230 | The default is | |
231 | .Dq no . | |
232 | .It Cm Compression | |
233 | Specifies whether to use compression. | |
234 | The argument must be | |
235 | .Dq yes | |
236 | or | |
237 | .Dq no . | |
238 | The default is | |
239 | .Dq no . | |
240 | .It Cm CompressionLevel | |
241 | Specifies the compression level to use if compression is enabled. | |
242 | The argument must be an integer from 1 (fast) to 9 (slow, best). | |
243 | The default level is 6, which is good for most applications. | |
244 | The meaning of the values is the same as in | |
245 | .Xr gzip 1 . | |
246 | Note that this option applies to protocol version 1 only. | |
247 | .It Cm ConnectionAttempts | |
248 | Specifies the number of tries (one per second) to make before exiting. | |
249 | The argument must be an integer. | |
250 | This may be useful in scripts if the connection sometimes fails. | |
251 | The default is 1. | |
09ab3296 | 252 | .It Cm ConnectTimeout |
c5786b30 | 253 | Specifies the timeout (in seconds) used when connecting to the |
254 | SSH server, instead of using the default system TCP timeout. | |
3cbc677d | 255 | This value is used only when the target is down or really unreachable, |
256 | not when it refuses the connection. | |
5e96b616 | 257 | .It Cm ControlMaster |
258 | Enables the sharing of multiple sessions over a single network connection. | |
259 | When set to | |
c5786b30 | 260 | .Dq yes , |
261 | .Xr ssh 1 | |
5e96b616 | 262 | will listen for connections on a control socket specified using the |
263 | .Cm ControlPath | |
264 | argument. | |
265 | Additional sessions can connect to this socket using the same | |
266 | .Cm ControlPath | |
267 | with | |
268 | .Cm ControlMaster | |
269 | set to | |
270 | .Dq no | |
9a5cfb58 | 271 | (the default). |
db98627d | 272 | These sessions will try to reuse the master instance's network connection |
6b0b0d65 | 273 | rather than initiating new ones, but will fall back to connecting normally |
274 | if the control socket does not exist, or is not listening. | |
275 | .Pp | |
0d34d6ce | 276 | Setting this to |
277 | .Dq ask | |
c5786b30 | 278 | will cause ssh |
0d34d6ce | 279 | to listen for control connections, but require confirmation using the |
280 | .Ev SSH_ASKPASS | |
281 | program before they are accepted (see | |
282 | .Xr ssh-add 1 | |
9a5cfb58 | 283 | for details). |
cc8ca1e6 | 284 | If the |
285 | .Cm ControlPath | |
c5786b30 | 286 | cannot be opened, |
287 | ssh will continue without connecting to a master instance. | |
9dfd96d6 | 288 | .Pp |
ef07103c | 289 | X11 and |
d313869b | 290 | .Xr ssh-agent 1 |
ef07103c | 291 | forwarding is supported over these multiplexed connections, however the |
8918b906 | 292 | display and agent forwarded will be the one belonging to the master |
d313869b | 293 | connection i.e. it is not possible to forward multiple displays or agents. |
ef07103c | 294 | .Pp |
9dfd96d6 | 295 | Two additional options allow for opportunistic multiplexing: try to use a |
296 | master connection but fall back to creating a new one if one does not already | |
297 | exist. | |
298 | These options are: | |
299 | .Dq auto | |
300 | and | |
301 | .Dq autoask . | |
302 | The latter requires confirmation like the | |
303 | .Dq ask | |
304 | option. | |
5e96b616 | 305 | .It Cm ControlPath |
a980cbd7 | 306 | Specify the path to the control socket used for connection sharing as described |
307 | in the | |
5e96b616 | 308 | .Cm ControlMaster |
699255b5 | 309 | section above or the string |
310 | .Dq none | |
311 | to disable connection sharing. | |
a980cbd7 | 312 | In the path, |
f7b8224d | 313 | .Ql %l |
314 | will be substituted by the local host name, | |
a980cbd7 | 315 | .Ql %h |
316 | will be substituted by the target host name, | |
317 | .Ql %p | |
c5786b30 | 318 | the port, and |
a980cbd7 | 319 | .Ql %r |
320 | by the remote login username. | |
9dfd96d6 | 321 | It is recommended that any |
322 | .Cm ControlPath | |
323 | used for opportunistic connection sharing include | |
5e7007ea | 324 | at least %h, %p, and %r. |
9dfd96d6 | 325 | This ensures that shared connections are uniquely identified. |
9a5cfb58 | 326 | .It Cm DynamicForward |
0b3950af | 327 | Specifies that a TCP port on the local machine be forwarded |
9a5cfb58 | 328 | over the secure channel, and the application |
329 | protocol is then used to determine where to connect to from the | |
330 | remote machine. | |
5ddc5eb4 | 331 | .Pp |
332 | The argument must be | |
333 | .Sm off | |
334 | .Oo Ar bind_address : Oc Ar port . | |
335 | .Sm on | |
336 | IPv6 addresses can be specified by enclosing addresses in square brackets or | |
337 | by using an alternative syntax: | |
338 | .Oo Ar bind_address Ns / Oc Ns Ar port . | |
339 | By default, the local port is bound in accordance with the | |
340 | .Cm GatewayPorts | |
341 | setting. | |
342 | However, an explicit | |
343 | .Ar bind_address | |
344 | may be used to bind the connection to a specific address. | |
345 | The | |
346 | .Ar bind_address | |
347 | of | |
348 | .Dq localhost | |
349 | indicates that the listening port be bound for local use only, while an | |
350 | empty address or | |
351 | .Sq * | |
352 | indicates that the port should be available from all interfaces. | |
353 | .Pp | |
9a5cfb58 | 354 | Currently the SOCKS4 and SOCKS5 protocols are supported, and |
c5786b30 | 355 | .Xr ssh 1 |
9a5cfb58 | 356 | will act as a SOCKS server. |
357 | Multiple forwardings may be specified, and | |
358 | additional forwardings can be given on the command line. | |
359 | Only the superuser can forward privileged ports. | |
f0677b69 | 360 | .It Cm EnableSSHKeysign |
361 | Setting this option to | |
362 | .Dq yes | |
363 | in the global client configuration file | |
364 | .Pa /etc/ssh/ssh_config | |
365 | enables the use of the helper program | |
366 | .Xr ssh-keysign 8 | |
367 | during | |
368 | .Cm HostbasedAuthentication . | |
369 | The argument must be | |
370 | .Dq yes | |
371 | or | |
372 | .Dq no . | |
373 | The default is | |
374 | .Dq no . | |
246bb171 | 375 | This option should be placed in the non-hostspecific section. |
f0677b69 | 376 | See |
377 | .Xr ssh-keysign 8 | |
378 | for more information. | |
588df31a | 379 | .It Cm EscapeChar |
380 | Sets the escape character (default: | |
381 | .Ql ~ ) . | |
382 | The escape character can also | |
383 | be set on the command line. | |
384 | The argument should be a single character, | |
385 | .Ql ^ | |
386 | followed by a letter, or | |
387 | .Dq none | |
388 | to disable the escape | |
389 | character entirely (making the connection transparent for binary | |
390 | data). | |
42ea6f5e | 391 | .It Cm ExitOnForwardFailure |
392 | Specifies whether | |
393 | .Xr ssh 1 | |
394 | should terminate the connection if it cannot set up all requested | |
1ce8114b | 395 | dynamic, tunnel, local, and remote port forwardings. |
42ea6f5e | 396 | The argument must be |
397 | .Dq yes | |
398 | or | |
399 | .Dq no . | |
400 | The default is | |
401 | .Dq no . | |
588df31a | 402 | .It Cm ForwardAgent |
403 | Specifies whether the connection to the authentication agent (if any) | |
404 | will be forwarded to the remote machine. | |
405 | The argument must be | |
406 | .Dq yes | |
407 | or | |
408 | .Dq no . | |
409 | The default is | |
410 | .Dq no . | |
dbcdea68 | 411 | .Pp |
a4e5acef | 412 | Agent forwarding should be enabled with caution. |
413 | Users with the ability to bypass file permissions on the remote host | |
414 | (for the agent's Unix-domain socket) | |
415 | can access the local agent through the forwarded connection. | |
416 | An attacker cannot obtain key material from the agent, | |
dbcdea68 | 417 | however they can perform operations on the keys that enable them to |
418 | authenticate using the identities loaded into the agent. | |
588df31a | 419 | .It Cm ForwardX11 |
420 | Specifies whether X11 connections will be automatically redirected | |
421 | over the secure channel and | |
422 | .Ev DISPLAY | |
423 | set. | |
424 | The argument must be | |
425 | .Dq yes | |
426 | or | |
427 | .Dq no . | |
428 | The default is | |
429 | .Dq no . | |
dbcdea68 | 430 | .Pp |
a4e5acef | 431 | X11 forwarding should be enabled with caution. |
432 | Users with the ability to bypass file permissions on the remote host | |
d73a67d7 | 433 | (for the user's X11 authorization database) |
a4e5acef | 434 | can access the local X11 display through the forwarded connection. |
d73a67d7 | 435 | An attacker may then be able to perform activities such as keystroke monitoring |
436 | if the | |
437 | .Cm ForwardX11Trusted | |
438 | option is also enabled. | |
439 | .It Cm ForwardX11Trusted | |
b2e90ab5 | 440 | If this option is set to |
c5786b30 | 441 | .Dq yes , |
442 | remote X11 clients will have full access to the original X11 display. | |
9a6b3b7a | 443 | .Pp |
d73a67d7 | 444 | If this option is set to |
c5786b30 | 445 | .Dq no , |
446 | remote X11 clients will be considered untrusted and prevented | |
d73a67d7 | 447 | from stealing or tampering with data belonging to trusted X11 |
448 | clients. | |
9a6b3b7a | 449 | Furthermore, the |
450 | .Xr xauth 1 | |
451 | token used for the session will be set to expire after 20 minutes. | |
452 | Remote clients will be refused access after this time. | |
d73a67d7 | 453 | .Pp |
454 | The default is | |
455 | .Dq no . | |
456 | .Pp | |
457 | See the X11 SECURITY extension specification for full details on | |
458 | the restrictions imposed on untrusted clients. | |
588df31a | 459 | .It Cm GatewayPorts |
460 | Specifies whether remote hosts are allowed to connect to local | |
461 | forwarded ports. | |
462 | By default, | |
c5786b30 | 463 | .Xr ssh 1 |
a4e5acef | 464 | binds local port forwardings to the loopback address. |
465 | This prevents other remote hosts from connecting to forwarded ports. | |
588df31a | 466 | .Cm GatewayPorts |
c5786b30 | 467 | can be used to specify that ssh |
588df31a | 468 | should bind local port forwardings to the wildcard address, |
469 | thus allowing remote hosts to connect to forwarded ports. | |
470 | The argument must be | |
471 | .Dq yes | |
472 | or | |
473 | .Dq no . | |
474 | The default is | |
475 | .Dq no . | |
476 | .It Cm GlobalKnownHostsFile | |
477 | Specifies a file to use for the global | |
478 | host key database instead of | |
479 | .Pa /etc/ssh/ssh_known_hosts . | |
7364bd04 | 480 | .It Cm GSSAPIAuthentication |
e8dd24a8 | 481 | Specifies whether user authentication based on GSSAPI is allowed. |
d0445371 | 482 | The default is |
2ecb78df | 483 | .Dq no . |
7364bd04 | 484 | Note that this option applies to protocol version 2 only. |
485 | .It Cm GSSAPIDelegateCredentials | |
486 | Forward (delegate) credentials to the server. | |
487 | The default is | |
488 | .Dq no . | |
489 | Note that this option applies to protocol version 2 only. | |
5c63c2ab | 490 | .It Cm HashKnownHosts |
491 | Indicates that | |
c5786b30 | 492 | .Xr ssh 1 |
5c63c2ab | 493 | should hash host names and addresses when they are added to |
140e3e97 | 494 | .Pa ~/.ssh/known_hosts . |
5c63c2ab | 495 | These hashed names may be used normally by |
c5786b30 | 496 | .Xr ssh 1 |
5c63c2ab | 497 | and |
c5786b30 | 498 | .Xr sshd 8 , |
5c63c2ab | 499 | but they do not reveal identifying information should the file's contents |
500 | be disclosed. | |
501 | The default is | |
502 | .Dq no . | |
f0817fbb | 503 | Note that existing names and addresses in known hosts files |
504 | will not be converted automatically, | |
505 | but may be manually hashed using | |
bdffbcdc | 506 | .Xr ssh-keygen 1 . |
588df31a | 507 | .It Cm HostbasedAuthentication |
508 | Specifies whether to try rhosts based authentication with public key | |
509 | authentication. | |
510 | The argument must be | |
511 | .Dq yes | |
512 | or | |
513 | .Dq no . | |
514 | The default is | |
515 | .Dq no . | |
516 | This option applies to protocol version 2 only and | |
517 | is similar to | |
518 | .Cm RhostsRSAAuthentication . | |
519 | .It Cm HostKeyAlgorithms | |
520 | Specifies the protocol version 2 host key algorithms | |
521 | that the client wants to use in order of preference. | |
522 | The default for this option is: | |
523 | .Dq ssh-rsa,ssh-dss . | |
524 | .It Cm HostKeyAlias | |
525 | Specifies an alias that should be used instead of the | |
526 | real host name when looking up or saving the host key | |
527 | in the host key database files. | |
c5786b30 | 528 | This option is useful for tunneling SSH connections |
588df31a | 529 | or for multiple servers running on a single host. |
530 | .It Cm HostName | |
531 | Specifies the real host name to log into. | |
532 | This can be used to specify nicknames or abbreviations for hosts. | |
c5786b30 | 533 | The default is the name given on the command line. |
588df31a | 534 | Numeric IP addresses are also permitted (both on the command line and in |
535 | .Cm HostName | |
536 | specifications). | |
3a065ed0 | 537 | .It Cm IdentitiesOnly |
538 | Specifies that | |
c5786b30 | 539 | .Xr ssh 1 |
3a065ed0 | 540 | should only use the authentication identity files configured in the |
1e9b1b82 | 541 | .Nm |
3a065ed0 | 542 | files, |
c5786b30 | 543 | even if |
544 | .Xr ssh-agent 1 | |
3a065ed0 | 545 | offers more identities. |
546 | The argument to this keyword must be | |
547 | .Dq yes | |
548 | or | |
549 | .Dq no . | |
c5786b30 | 550 | This option is intended for situations where ssh-agent |
3a065ed0 | 551 | offers many different identities. |
552 | The default is | |
553 | .Dq no . | |
030723f9 | 554 | .It Cm IdentityFile |
555 | Specifies a file from which the user's RSA or DSA authentication identity | |
556 | is read. | |
557 | The default is | |
558 | .Pa ~/.ssh/identity | |
559 | for protocol version 1, and | |
560 | .Pa ~/.ssh/id_rsa | |
561 | and | |
562 | .Pa ~/.ssh/id_dsa | |
563 | for protocol version 2. | |
564 | Additionally, any identities represented by the authentication agent | |
565 | will be used for authentication. | |
8cffe22a | 566 | .Pp |
030723f9 | 567 | The file name may use the tilde |
99d18e3e | 568 | syntax to refer to a user's home directory or one of the following |
8cffe22a | 569 | escape characters: |
570 | .Ql %d | |
571 | (local user's home directory), | |
572 | .Ql %u | |
573 | (local user name), | |
574 | .Ql %l | |
575 | (local host name), | |
576 | .Ql %h | |
577 | (remote host name) or | |
b4d7dedd | 578 | .Ql %r |
8cffe22a | 579 | (remote user name). |
580 | .Pp | |
030723f9 | 581 | It is possible to have |
582 | multiple identity files specified in configuration files; all these | |
583 | identities will be tried in sequence. | |
530c2ec0 | 584 | .It Cm KbdInteractiveAuthentication |
585 | Specifies whether to use keyboard-interactive authentication. | |
586 | The argument to this keyword must be | |
587 | .Dq yes | |
588 | or | |
589 | .Dq no . | |
590 | The default is | |
591 | .Dq yes . | |
396070f8 | 592 | .It Cm KbdInteractiveDevices |
593 | Specifies the list of methods to use in keyboard-interactive authentication. | |
594 | Multiple method names must be comma-separated. | |
595 | The default is to use the server specified list. | |
2963b207 | 596 | The methods available vary depending on what the server supports. |
597 | For an OpenSSH server, | |
598 | it may be zero or more of: | |
599 | .Dq bsdauth , | |
600 | .Dq pam , | |
601 | and | |
602 | .Dq skey . | |
d20f3c9e | 603 | .It Cm LocalCommand |
604 | Specifies a command to execute on the local machine after successfully | |
605 | connecting to the server. | |
606 | The command string extends to the end of the line, and is executed with | |
eb86ca9d | 607 | the user's shell. |
e9d0b573 | 608 | The following escape character substitutions will be performed: |
609 | .Ql %d | |
610 | (local user's home directory), | |
611 | .Ql %h | |
612 | (remote host name), | |
613 | .Ql %l | |
614 | (local host name), | |
615 | .Ql %n | |
616 | (host name as provided on the command line), | |
617 | .Ql %p | |
618 | (remote port), | |
619 | .Ql %r | |
620 | (remote user name) or | |
621 | .Ql %u | |
622 | (local user name). | |
d20f3c9e | 623 | This directive is ignored unless |
624 | .Cm PermitLocalCommand | |
625 | has been enabled. | |
588df31a | 626 | .It Cm LocalForward |
0b3950af | 627 | Specifies that a TCP port on the local machine be forwarded over |
588df31a | 628 | the secure channel to the specified host and port from the remote machine. |
ecda4ffb | 629 | The first argument must be |
3867aa0a | 630 | .Sm off |
ecda4ffb | 631 | .Oo Ar bind_address : Oc Ar port |
3867aa0a | 632 | .Sm on |
ecda4ffb | 633 | and the second argument must be |
634 | .Ar host : Ns Ar hostport . | |
cd8f998c | 635 | IPv6 addresses can be specified by enclosing addresses in square brackets or |
3867aa0a | 636 | by using an alternative syntax: |
ecda4ffb | 637 | .Oo Ar bind_address Ns / Oc Ns Ar port |
638 | and | |
639 | .Ar host Ns / Ns Ar hostport . | |
cd8f998c | 640 | Multiple forwardings may be specified, and additional forwardings can be |
3867aa0a | 641 | given on the command line. |
588df31a | 642 | Only the superuser can forward privileged ports. |
3867aa0a | 643 | By default, the local port is bound in accordance with the |
644 | .Cm GatewayPorts | |
645 | setting. | |
646 | However, an explicit | |
647 | .Ar bind_address | |
648 | may be used to bind the connection to a specific address. | |
649 | The | |
650 | .Ar bind_address | |
651 | of | |
652 | .Dq localhost | |
cd8f998c | 653 | indicates that the listening port be bound for local use only, while an |
654 | empty address or | |
655 | .Sq * | |
3867aa0a | 656 | indicates that the port should be available from all interfaces. |
588df31a | 657 | .It Cm LogLevel |
658 | Gives the verbosity level that is used when logging messages from | |
c5786b30 | 659 | .Xr ssh 1 . |
588df31a | 660 | The possible values are: |
c5786b30 | 661 | QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. |
a4e5acef | 662 | The default is INFO. |
663 | DEBUG and DEBUG1 are equivalent. | |
664 | DEBUG2 and DEBUG3 each specify higher levels of verbose output. | |
588df31a | 665 | .It Cm MACs |
666 | Specifies the MAC (message authentication code) algorithms | |
667 | in order of preference. | |
668 | The MAC algorithm is used in protocol version 2 | |
669 | for data integrity protection. | |
670 | Multiple algorithms must be comma-separated. | |
c5786b30 | 671 | The default is: |
bbc77085 | 672 | .Bd -literal -offset indent |
673 | hmac-md5,hmac-sha1,umac-64@openssh.com, | |
674 | hmac-ripemd160,hmac-sha1-96,hmac-md5-96 | |
675 | .Ed | |
588df31a | 676 | .It Cm NoHostAuthenticationForLocalhost |
677 | This option can be used if the home directory is shared across machines. | |
678 | In this case localhost will refer to a different machine on each of | |
679 | the machines and the user will get many warnings about changed host keys. | |
680 | However, this option disables host authentication for localhost. | |
681 | The argument to this keyword must be | |
682 | .Dq yes | |
683 | or | |
684 | .Dq no . | |
685 | The default is to check the host key for localhost. | |
686 | .It Cm NumberOfPasswordPrompts | |
687 | Specifies the number of password prompts before giving up. | |
688 | The argument to this keyword must be an integer. | |
c5786b30 | 689 | The default is 3. |
588df31a | 690 | .It Cm PasswordAuthentication |
691 | Specifies whether to use password authentication. | |
692 | The argument to this keyword must be | |
693 | .Dq yes | |
694 | or | |
695 | .Dq no . | |
696 | The default is | |
697 | .Dq yes . | |
d20f3c9e | 698 | .It Cm PermitLocalCommand |
699 | Allow local command execution via the | |
700 | .Ic LocalCommand | |
701 | option or using the | |
64925c6d | 702 | .Ic !\& Ns Ar command |
d20f3c9e | 703 | escape sequence in |
704 | .Xr ssh 1 . | |
705 | The argument must be | |
706 | .Dq yes | |
707 | or | |
708 | .Dq no . | |
709 | The default is | |
710 | .Dq no . | |
030723f9 | 711 | .It Cm Port |
712 | Specifies the port number to connect on the remote host. | |
c5786b30 | 713 | The default is 22. |
588df31a | 714 | .It Cm PreferredAuthentications |
715 | Specifies the order in which the client should try protocol 2 | |
3cbc677d | 716 | authentication methods. |
4e5038f7 | 717 | This allows a client to prefer one method (e.g.\& |
588df31a | 718 | .Cm keyboard-interactive ) |
4e5038f7 | 719 | over another method (e.g.\& |
588df31a | 720 | .Cm password ) |
721 | The default for this option is: | |
f127d8a4 | 722 | .Do gssapi-with-mic , |
723 | hostbased, | |
724 | publickey, | |
725 | keyboard-interactive, | |
726 | password | |
727 | .Dc . | |
588df31a | 728 | .It Cm Protocol |
729 | Specifies the protocol versions | |
c5786b30 | 730 | .Xr ssh 1 |
588df31a | 731 | should support in order of preference. |
732 | The possible values are | |
c5786b30 | 733 | .Sq 1 |
588df31a | 734 | and |
c5786b30 | 735 | .Sq 2 . |
588df31a | 736 | Multiple versions must be comma-separated. |
737 | The default is | |
738 | .Dq 2,1 . | |
c5786b30 | 739 | This means that ssh |
588df31a | 740 | tries version 2 and falls back to version 1 |
741 | if version 2 is not available. | |
742 | .It Cm ProxyCommand | |
743 | Specifies the command to use to connect to the server. | |
744 | The command | |
745 | string extends to the end of the line, and is executed with | |
eb86ca9d | 746 | the user's shell. |
588df31a | 747 | In the command string, |
748 | .Ql %h | |
749 | will be substituted by the host name to | |
750 | connect and | |
751 | .Ql %p | |
752 | by the port. | |
753 | The command can be basically anything, | |
754 | and should read from its standard input and write to its standard output. | |
755 | It should eventually connect an | |
756 | .Xr sshd 8 | |
757 | server running on some machine, or execute | |
758 | .Ic sshd -i | |
759 | somewhere. | |
760 | Host key management will be done using the | |
761 | HostName of the host being connected (defaulting to the name typed by | |
762 | the user). | |
a4e5acef | 763 | Setting the command to |
764 | .Dq none | |
f78bde70 | 765 | disables this option entirely. |
588df31a | 766 | Note that |
767 | .Cm CheckHostIP | |
768 | is not available for connects with a proxy command. | |
769 | .Pp | |
2b610872 | 770 | This directive is useful in conjunction with |
771 | .Xr nc 1 | |
772 | and its proxy support. | |
9fa42d41 | 773 | For example, the following directive would connect via an HTTP proxy at |
2b610872 | 774 | 192.0.2.0: |
775 | .Bd -literal -offset 3n | |
776 | ProxyCommand /usr/bin/nc -X connect -x 192.0.2.0:8080 %h %p | |
777 | .Ed | |
588df31a | 778 | .It Cm PubkeyAuthentication |
779 | Specifies whether to try public key authentication. | |
780 | The argument to this keyword must be | |
781 | .Dq yes | |
782 | or | |
783 | .Dq no . | |
784 | The default is | |
785 | .Dq yes . | |
786 | This option applies to protocol version 2 only. | |
db175906 | 787 | .It Cm RekeyLimit |
788 | Specifies the maximum amount of data that may be transmitted before the | |
0ce89457 | 789 | session key is renegotiated. |
db175906 | 790 | The argument is the number of bytes, with an optional suffix of |
0ce89457 | 791 | .Sq K , |
792 | .Sq M , | |
db175906 | 793 | or |
0ce89457 | 794 | .Sq G |
db175906 | 795 | to indicate Kilobytes, Megabytes, or Gigabytes, respectively. |
796 | The default is between | |
c5786b30 | 797 | .Sq 1G |
db175906 | 798 | and |
c5786b30 | 799 | .Sq 4G , |
db175906 | 800 | depending on the cipher. |
0ce89457 | 801 | This option applies to protocol version 2 only. |
588df31a | 802 | .It Cm RemoteForward |
0b3950af | 803 | Specifies that a TCP port on the remote machine be forwarded over |
588df31a | 804 | the secure channel to the specified host and port from the local machine. |
ecda4ffb | 805 | The first argument must be |
3867aa0a | 806 | .Sm off |
ecda4ffb | 807 | .Oo Ar bind_address : Oc Ar port |
6d7a9e8f | 808 | .Sm on |
ecda4ffb | 809 | and the second argument must be |
810 | .Ar host : Ns Ar hostport . | |
811 | IPv6 addresses can be specified by enclosing addresses in square brackets | |
812 | or by using an alternative syntax: | |
813 | .Oo Ar bind_address Ns / Oc Ns Ar port | |
814 | and | |
815 | .Ar host Ns / Ns Ar hostport . | |
588df31a | 816 | Multiple forwardings may be specified, and additional |
817 | forwardings can be given on the command line. | |
818 | Only the superuser can forward privileged ports. | |
3867aa0a | 819 | .Pp |
820 | If the | |
821 | .Ar bind_address | |
822 | is not specified, the default is to only bind to loopback addresses. | |
823 | If the | |
824 | .Ar bind_address | |
825 | is | |
826 | .Ql * | |
827 | or an empty string, then the forwarding is requested to listen on all | |
828 | interfaces. | |
829 | Specifying a remote | |
830 | .Ar bind_address | |
cd8f998c | 831 | will only succeed if the server's |
832 | .Cm GatewayPorts | |
3867aa0a | 833 | option is enabled (see |
cd8f998c | 834 | .Xr sshd_config 5 ) . |
588df31a | 835 | .It Cm RhostsRSAAuthentication |
836 | Specifies whether to try rhosts based authentication with RSA host | |
837 | authentication. | |
838 | The argument must be | |
839 | .Dq yes | |
840 | or | |
841 | .Dq no . | |
842 | The default is | |
843 | .Dq no . | |
844 | This option applies to protocol version 1 only and requires | |
c5786b30 | 845 | .Xr ssh 1 |
588df31a | 846 | to be setuid root. |
847 | .It Cm RSAAuthentication | |
848 | Specifies whether to try RSA authentication. | |
849 | The argument to this keyword must be | |
850 | .Dq yes | |
851 | or | |
852 | .Dq no . | |
853 | RSA authentication will only be | |
854 | attempted if the identity file exists, or an authentication agent is | |
855 | running. | |
856 | The default is | |
857 | .Dq yes . | |
858 | Note that this option applies to protocol version 1 only. | |
61a2c1da | 859 | .It Cm SendEnv |
860 | Specifies what variables from the local | |
861 | .Xr environ 7 | |
862 | should be sent to the server. | |
c5786b30 | 863 | Note that environment passing is only supported for protocol 2. |
864 | The server must also support it, and the server must be configured to | |
b8b9f2e6 | 865 | accept these environment variables. |
61a2c1da | 866 | Refer to |
867 | .Cm AcceptEnv | |
868 | in | |
869 | .Xr sshd_config 5 | |
870 | for how to configure the server. | |
95d46d8f | 871 | Variables are specified by name, which may contain wildcard characters. |
b8b9f2e6 | 872 | Multiple environment variables may be separated by whitespace or spread |
61a2c1da | 873 | across multiple |
874 | .Cm SendEnv | |
875 | directives. | |
876 | The default is not to send any environment variables. | |
436a5ff9 | 877 | .Pp |
878 | See | |
879 | .Sx PATTERNS | |
880 | for more information on patterns. | |
5d8d32a3 | 881 | .It Cm ServerAliveCountMax |
79e46360 | 882 | Sets the number of server alive messages (see below) which may be |
5d8d32a3 | 883 | sent without |
c5786b30 | 884 | .Xr ssh 1 |
5d8d32a3 | 885 | receiving any messages back from the server. |
886 | If this threshold is reached while server alive messages are being sent, | |
c5786b30 | 887 | ssh will disconnect from the server, terminating the session. |
5d8d32a3 | 888 | It is important to note that the use of server alive messages is very |
889 | different from | |
890 | .Cm TCPKeepAlive | |
891 | (below). | |
892 | The server alive messages are sent through the encrypted channel | |
893 | and therefore will not be spoofable. | |
894 | The TCP keepalive option enabled by | |
895 | .Cm TCPKeepAlive | |
896 | is spoofable. | |
897 | The server alive mechanism is valuable when the client or | |
898 | server depend on knowing when a connection has become inactive. | |
899 | .Pp | |
900 | The default value is 3. | |
901 | If, for example, | |
902 | .Cm ServerAliveInterval | |
c5786b30 | 903 | (see below) is set to 15 and |
5d8d32a3 | 904 | .Cm ServerAliveCountMax |
c5786b30 | 905 | is left at the default, if the server becomes unresponsive, |
906 | ssh will disconnect after approximately 45 seconds. | |
2d762582 | 907 | This option applies to protocol version 2 only. |
030723f9 | 908 | .It Cm ServerAliveInterval |
909 | Sets a timeout interval in seconds after which if no data has been received | |
910 | from the server, | |
c5786b30 | 911 | .Xr ssh 1 |
030723f9 | 912 | will send a message through the encrypted |
913 | channel to request a response from the server. | |
914 | The default | |
915 | is 0, indicating that these messages will not be sent to the server. | |
916 | This option applies to protocol version 2 only. | |
588df31a | 917 | .It Cm SmartcardDevice |
3cbc677d | 918 | Specifies which smartcard device to use. |
919 | The argument to this keyword is the device | |
c5786b30 | 920 | .Xr ssh 1 |
588df31a | 921 | should use to communicate with a smartcard used for storing the user's |
3cbc677d | 922 | private RSA key. |
923 | By default, no device is specified and smartcard support is not activated. | |
588df31a | 924 | .It Cm StrictHostKeyChecking |
925 | If this flag is set to | |
926 | .Dq yes , | |
c5786b30 | 927 | .Xr ssh 1 |
588df31a | 928 | will never automatically add host keys to the |
140e3e97 | 929 | .Pa ~/.ssh/known_hosts |
588df31a | 930 | file, and refuses to connect to hosts whose host key has changed. |
931 | This provides maximum protection against trojan horse attacks, | |
c5786b30 | 932 | though it can be annoying when the |
588df31a | 933 | .Pa /etc/ssh/ssh_known_hosts |
c5786b30 | 934 | file is poorly maintained or when connections to new hosts are |
588df31a | 935 | frequently made. |
936 | This option forces the user to manually | |
937 | add all new hosts. | |
938 | If this flag is set to | |
939 | .Dq no , | |
c5786b30 | 940 | ssh will automatically add new host keys to the |
588df31a | 941 | user known hosts files. |
942 | If this flag is set to | |
943 | .Dq ask , | |
944 | new host keys | |
945 | will be added to the user known host files only after the user | |
946 | has confirmed that is what they really want to do, and | |
c5786b30 | 947 | ssh will refuse to connect to hosts whose host key has changed. |
588df31a | 948 | The host keys of |
949 | known hosts will be verified automatically in all cases. | |
950 | The argument must be | |
951 | .Dq yes , | |
c5786b30 | 952 | .Dq no , |
588df31a | 953 | or |
954 | .Dq ask . | |
955 | The default is | |
956 | .Dq ask . | |
fd573618 | 957 | .It Cm TCPKeepAlive |
958 | Specifies whether the system should send TCP keepalive messages to the | |
959 | other side. | |
960 | If they are sent, death of the connection or crash of one | |
961 | of the machines will be properly noticed. | |
962 | However, this means that | |
963 | connections will die if the route is down temporarily, and some people | |
964 | find it annoying. | |
965 | .Pp | |
966 | The default is | |
967 | .Dq yes | |
968 | (to send TCP keepalive messages), and the client will notice | |
969 | if the network goes down or the remote host dies. | |
970 | This is important in scripts, and many users want it too. | |
971 | .Pp | |
972 | To disable TCP keepalive messages, the value should be set to | |
973 | .Dq no . | |
d20f3c9e | 974 | .It Cm Tunnel |
06fa4ac1 | 975 | Request |
d20f3c9e | 976 | .Xr tun 4 |
a274ba38 | 977 | device forwarding between the client and the server. |
d20f3c9e | 978 | The argument must be |
a4f24bf8 | 979 | .Dq yes , |
06fa4ac1 | 980 | .Dq point-to-point |
981 | (layer 3), | |
982 | .Dq ethernet | |
983 | (layer 2), | |
d20f3c9e | 984 | or |
985 | .Dq no . | |
06fa4ac1 | 986 | Specifying |
987 | .Dq yes | |
988 | requests the default tunnel mode, which is | |
989 | .Dq point-to-point . | |
d20f3c9e | 990 | The default is |
991 | .Dq no . | |
992 | .It Cm TunnelDevice | |
06fa4ac1 | 993 | Specifies the |
d20f3c9e | 994 | .Xr tun 4 |
06fa4ac1 | 995 | devices to open on the client |
996 | .Pq Ar local_tun | |
997 | and the server | |
998 | .Pq Ar remote_tun . | |
999 | .Pp | |
1000 | The argument must be | |
1001 | .Sm off | |
1002 | .Ar local_tun Op : Ar remote_tun . | |
1003 | .Sm on | |
1004 | The devices may be specified by numerical ID or the keyword | |
1005 | .Dq any , | |
1006 | which uses the next available tunnel device. | |
1007 | If | |
1008 | .Ar remote_tun | |
1009 | is not specified, it defaults to | |
1010 | .Dq any . | |
1011 | The default is | |
1012 | .Dq any:any . | |
0c9851b1 | 1013 | .It Cm UsePrivilegedPort |
1014 | Specifies whether to use a privileged port for outgoing connections. | |
1015 | The argument must be | |
1016 | .Dq yes | |
1017 | or | |
1018 | .Dq no . | |
1019 | The default is | |
1020 | .Dq no . | |
1021 | If set to | |
c5786b30 | 1022 | .Dq yes , |
1023 | .Xr ssh 1 | |
0c9851b1 | 1024 | must be setuid root. |
1025 | Note that this option must be set to | |
1026 | .Dq yes | |
1027 | for | |
1028 | .Cm RhostsRSAAuthentication | |
1029 | with older servers. | |
588df31a | 1030 | .It Cm User |
1031 | Specifies the user to log in as. | |
1032 | This can be useful when a different user name is used on different machines. | |
1033 | This saves the trouble of | |
1034 | having to remember to give the user name on the command line. | |
1035 | .It Cm UserKnownHostsFile | |
1036 | Specifies a file to use for the user | |
1037 | host key database instead of | |
140e3e97 | 1038 | .Pa ~/.ssh/known_hosts . |
21289cd0 | 1039 | .It Cm VerifyHostKeyDNS |
1040 | Specifies whether to verify the remote key using DNS and SSHFP resource | |
1041 | records. | |
0161a13d | 1042 | If this option is set to |
1043 | .Dq yes , | |
dd376e92 | 1044 | the client will implicitly trust keys that match a secure fingerprint |
0161a13d | 1045 | from DNS. |
1046 | Insecure fingerprints will be handled as if this option was set to | |
1047 | .Dq ask . | |
1048 | If this option is set to | |
1049 | .Dq ask , | |
1050 | information on fingerprint match will be displayed, but the user will still | |
1051 | need to confirm new host keys according to the | |
1052 | .Cm StrictHostKeyChecking | |
1053 | option. | |
1054 | The argument must be | |
1055 | .Dq yes , | |
c5786b30 | 1056 | .Dq no , |
dd376e92 | 1057 | or |
1058 | .Dq ask . | |
21289cd0 | 1059 | The default is |
1060 | .Dq no . | |
0f92946c | 1061 | Note that this option applies to protocol version 2 only. |
c5786b30 | 1062 | .Pp |
1063 | See also | |
1064 | .Sx VERIFYING HOST KEYS | |
1065 | in | |
1066 | .Xr ssh 1 . | |
588df31a | 1067 | .It Cm XAuthLocation |
57ff5eeb | 1068 | Specifies the full pathname of the |
588df31a | 1069 | .Xr xauth 1 |
1070 | program. | |
1071 | The default is | |
1072 | .Pa /usr/X11R6/bin/xauth . | |
1073 | .El | |
de4f5093 | 1074 | .Sh PATTERNS |
1075 | A | |
1076 | .Em pattern | |
1077 | consists of zero or more non-whitespace characters, | |
1078 | .Sq * | |
1079 | (a wildcard that matches zero or more characters), | |
1080 | or | |
1081 | .Sq ?\& | |
1082 | (a wildcard that matches exactly one character). | |
1083 | For example, to specify a set of declarations for any host in the | |
1084 | .Dq .co.uk | |
1085 | set of domains, | |
1086 | the following pattern could be used: | |
1087 | .Pp | |
1088 | .Dl Host *.co.uk | |
1089 | .Pp | |
1090 | The following pattern | |
1091 | would match any host in the 192.168.0.[0-9] network range: | |
1092 | .Pp | |
1093 | .Dl Host 192.168.0.? | |
1094 | .Pp | |
1095 | A | |
1096 | .Em pattern-list | |
1097 | is a comma-separated list of patterns. | |
1098 | Patterns within pattern-lists may be negated | |
1099 | by preceding them with an exclamation mark | |
1100 | .Pq Sq !\& . | |
1101 | For example, | |
1102 | to allow a key to be used from anywhere within an organisation | |
1103 | except from the | |
1104 | .Dq dialup | |
1105 | pool, | |
1106 | the following entry (in authorized_keys) could be used: | |
1107 | .Pp | |
1108 | .Dl from=\&"!*.dialup.example.com,*.example.com\&" | |
588df31a | 1109 | .Sh FILES |
1110 | .Bl -tag -width Ds | |
140e3e97 | 1111 | .It Pa ~/.ssh/config |
588df31a | 1112 | This is the per-user configuration file. |
1113 | The format of this file is described above. | |
c5786b30 | 1114 | This file is used by the SSH client. |
e1520719 | 1115 | Because of the potential for abuse, this file must have strict permissions: |
1116 | read/write for the user, and not accessible by others. | |
588df31a | 1117 | .It Pa /etc/ssh/ssh_config |
1118 | Systemwide configuration file. | |
1119 | This file provides defaults for those | |
1120 | values that are not specified in the user's configuration file, and | |
1121 | for those users who do not have a configuration file. | |
1122 | This file must be world-readable. | |
1123 | .El | |
be193d89 | 1124 | .Sh SEE ALSO |
1125 | .Xr ssh 1 | |
588df31a | 1126 | .Sh AUTHORS |
1127 | OpenSSH is a derivative of the original and free | |
1128 | ssh 1.2.12 release by Tatu Ylonen. | |
1129 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, | |
1130 | Theo de Raadt and Dug Song | |
1131 | removed many bugs, re-added newer features and | |
1132 | created OpenSSH. | |
1133 | Markus Friedl contributed the support for SSH | |
1134 | protocol versions 1.5 and 2.0. |