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884dc78b | 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 | .\" | |
fa0f0f45 | 37 | .\" $OpenBSD: ssh_config.5,v 1.102 2007/08/15 12:13:41 stevesk Exp $ |
38 | .Dd $Mdocdate: August 15 2007 $ | |
884dc78b | 39 | .Dt SSH_CONFIG 5 |
40 | .Os | |
41 | .Sh NAME | |
42 | .Nm ssh_config | |
43 | .Nd OpenSSH SSH client configuration files | |
44 | .Sh SYNOPSIS | |
0b90ac93 | 45 | .Nm ~/.ssh/config |
46 | .Nm /etc/ssh/ssh_config | |
884dc78b | 47 | .Sh DESCRIPTION |
30460aeb | 48 | .Xr ssh 1 |
884dc78b | 49 | obtains configuration data from the following sources in |
50 | the following order: | |
30460aeb | 51 | .Pp |
d03f4262 | 52 | .Bl -enum -offset indent -compact |
53 | .It | |
54 | command-line options | |
55 | .It | |
44a053a3 | 56 | user's configuration file |
2ce0bfe4 | 57 | .Pq Pa ~/.ssh/config |
d03f4262 | 58 | .It |
d6862c36 | 59 | GSSAPI configuration file |
d03f4262 | 60 | .Pq Pa $HOME/.ssh/config.gssapi |
61 | .It | |
d6862c36 | 62 | Kerberos configuration file |
d03f4262 | 63 | .Pq Pa $HOME/.ssh/config.krb |
64 | .It | |
d03f4262 | 65 | system-wide configuration file |
66 | .Pq Pa /etc/ssh/ssh_config | |
44a053a3 | 67 | .El |
884dc78b | 68 | .Pp |
69 | For each parameter, the first obtained value | |
70 | will be used. | |
dfddba3d | 71 | The configuration files contain sections separated by |
884dc78b | 72 | .Dq Host |
73 | specifications, and that section is only applied for hosts that | |
74 | match one of the patterns given in the specification. | |
75 | The matched host name is the one given on the command line. | |
76 | .Pp | |
77 | Since the first obtained value for each parameter is used, more | |
78 | host-specific declarations should be given near the beginning of the | |
79 | file, and general defaults at the end. | |
80 | .Pp | |
81 | The configuration file has the following format: | |
82 | .Pp | |
83 | Empty lines and lines starting with | |
84 | .Ql # | |
85 | are comments. | |
884dc78b | 86 | Otherwise a line is of the format |
87 | .Dq keyword arguments . | |
88 | Configuration options may be separated by whitespace or | |
89 | optional whitespace and exactly one | |
90 | .Ql = ; | |
91 | the latter format is useful to avoid the need to quote whitespace | |
92 | when specifying configuration options using the | |
93 | .Nm ssh , | |
30460aeb | 94 | .Nm scp , |
884dc78b | 95 | and |
96 | .Nm sftp | |
97 | .Fl o | |
98 | option. | |
30460aeb | 99 | Arguments may optionally be enclosed in double quotes |
100 | .Pq \&" | |
101 | in order to represent arguments containing spaces. | |
884dc78b | 102 | .Pp |
103 | The possible | |
104 | keywords and their meanings are as follows (note that | |
105 | keywords are case-insensitive and arguments are case-sensitive): | |
106 | .Bl -tag -width Ds | |
107 | .It Cm Host | |
108 | Restricts the following declarations (up to the next | |
109 | .Cm Host | |
110 | keyword) to be only for those hosts that match one of the patterns | |
111 | given after the keyword. | |
884dc78b | 112 | A single |
30460aeb | 113 | .Ql * |
884dc78b | 114 | as a pattern can be used to provide global |
115 | defaults for all hosts. | |
116 | The host is the | |
117 | .Ar hostname | |
30460aeb | 118 | argument given on the command line (i.e. the name is not converted to |
884dc78b | 119 | a canonicalized host name before matching). |
30460aeb | 120 | .Pp |
121 | See | |
122 | .Sx PATTERNS | |
123 | for more information on patterns. | |
7cac2b65 | 124 | .It Cm AddressFamily |
125 | Specifies which address family to use when connecting. | |
126 | Valid arguments are | |
127 | .Dq any , | |
128 | .Dq inet | |
30460aeb | 129 | (use IPv4 only), or |
7cac2b65 | 130 | .Dq inet6 |
dfddba3d | 131 | (use IPv6 only). |
884dc78b | 132 | .It Cm BatchMode |
133 | If set to | |
134 | .Dq yes , | |
135 | passphrase/password querying will be disabled. | |
136 | This option is useful in scripts and other batch jobs where no user | |
137 | is present to supply the password. | |
138 | The argument must be | |
139 | .Dq yes | |
140 | or | |
141 | .Dq no . | |
142 | The default is | |
143 | .Dq no . | |
144 | .It Cm BindAddress | |
2ce0bfe4 | 145 | Use the specified address on the local machine as the source address of |
146 | the connection. | |
147 | Only useful on systems with more than one address. | |
884dc78b | 148 | Note that this option does not work if |
149 | .Cm UsePrivilegedPort | |
150 | is set to | |
151 | .Dq yes . | |
152 | .It Cm ChallengeResponseAuthentication | |
30460aeb | 153 | Specifies whether to use challenge-response authentication. |
884dc78b | 154 | The argument to this keyword must be |
155 | .Dq yes | |
156 | or | |
157 | .Dq no . | |
158 | The default is | |
159 | .Dq yes . | |
160 | .It Cm CheckHostIP | |
161 | If this flag is set to | |
162 | .Dq yes , | |
30460aeb | 163 | .Xr ssh 1 |
164 | will additionally check the host IP address in the | |
884dc78b | 165 | .Pa known_hosts |
166 | file. | |
167 | This allows ssh to detect if a host key changed due to DNS spoofing. | |
168 | If the option is set to | |
169 | .Dq no , | |
170 | the check will not be executed. | |
171 | The default is | |
172 | .Dq yes . | |
173 | .It Cm Cipher | |
174 | Specifies the cipher to use for encrypting the session | |
175 | in protocol version 1. | |
176 | Currently, | |
177 | .Dq blowfish , | |
178 | .Dq 3des , | |
179 | and | |
180 | .Dq des | |
181 | are supported. | |
182 | .Ar des | |
183 | is only supported in the | |
30460aeb | 184 | .Xr ssh 1 |
884dc78b | 185 | client for interoperability with legacy protocol 1 implementations |
186 | that do not support the | |
187 | .Ar 3des | |
bfe49944 | 188 | cipher. |
189 | Its use is strongly discouraged due to cryptographic weaknesses. | |
884dc78b | 190 | The default is |
191 | .Dq 3des . | |
192 | .It Cm Ciphers | |
193 | Specifies the ciphers allowed for protocol version 2 | |
194 | in order of preference. | |
195 | Multiple ciphers must be comma-separated. | |
7e82606e | 196 | The supported ciphers are |
197 | .Dq 3des-cbc , | |
198 | .Dq aes128-cbc , | |
199 | .Dq aes192-cbc , | |
200 | .Dq aes256-cbc , | |
201 | .Dq aes128-ctr , | |
202 | .Dq aes192-ctr , | |
203 | .Dq aes256-ctr , | |
2ce0bfe4 | 204 | .Dq arcfour128 , |
205 | .Dq arcfour256 , | |
7e82606e | 206 | .Dq arcfour , |
207 | .Dq blowfish-cbc , | |
208 | and | |
209 | .Dq cast128-cbc . | |
30460aeb | 210 | The default is: |
211 | .Bd -literal -offset 3n | |
212 | aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128, | |
213 | arcfour256,arcfour,aes192-cbc,aes256-cbc,aes128-ctr, | |
214 | aes192-ctr,aes256-ctr | |
884dc78b | 215 | .Ed |
216 | .It Cm ClearAllForwardings | |
30460aeb | 217 | Specifies that all local, remote, and dynamic port forwardings |
884dc78b | 218 | specified in the configuration files or on the command line be |
bfe49944 | 219 | cleared. |
220 | This option is primarily useful when used from the | |
30460aeb | 221 | .Xr ssh 1 |
884dc78b | 222 | command line to clear port forwardings set in |
223 | configuration files, and is automatically set by | |
224 | .Xr scp 1 | |
225 | and | |
226 | .Xr sftp 1 . | |
227 | The argument must be | |
228 | .Dq yes | |
229 | or | |
230 | .Dq no . | |
231 | The default is | |
232 | .Dq no . | |
233 | .It Cm Compression | |
234 | Specifies whether to use compression. | |
235 | The argument must be | |
236 | .Dq yes | |
237 | or | |
238 | .Dq no . | |
239 | The default is | |
240 | .Dq no . | |
241 | .It Cm CompressionLevel | |
242 | Specifies the compression level to use if compression is enabled. | |
243 | The argument must be an integer from 1 (fast) to 9 (slow, best). | |
244 | The default level is 6, which is good for most applications. | |
245 | The meaning of the values is the same as in | |
246 | .Xr gzip 1 . | |
247 | Note that this option applies to protocol version 1 only. | |
248 | .It Cm ConnectionAttempts | |
249 | Specifies the number of tries (one per second) to make before exiting. | |
250 | The argument must be an integer. | |
251 | This may be useful in scripts if the connection sometimes fails. | |
252 | The default is 1. | |
7cac2b65 | 253 | .It Cm ConnectTimeout |
30460aeb | 254 | Specifies the timeout (in seconds) used when connecting to the |
255 | SSH server, instead of using the default system TCP timeout. | |
7cac2b65 | 256 | This value is used only when the target is down or really unreachable, |
257 | not when it refuses the connection. | |
7e82606e | 258 | .It Cm ControlMaster |
259 | Enables the sharing of multiple sessions over a single network connection. | |
260 | When set to | |
30460aeb | 261 | .Dq yes , |
262 | .Xr ssh 1 | |
7e82606e | 263 | will listen for connections on a control socket specified using the |
264 | .Cm ControlPath | |
265 | argument. | |
266 | Additional sessions can connect to this socket using the same | |
267 | .Cm ControlPath | |
268 | with | |
269 | .Cm ControlMaster | |
270 | set to | |
271 | .Dq no | |
272 | (the default). | |
08822d99 | 273 | These sessions will try to reuse the master instance's network connection |
274 | rather than initiating new ones, but will fall back to connecting normally | |
275 | if the control socket does not exist, or is not listening. | |
276 | .Pp | |
7e82606e | 277 | Setting this to |
278 | .Dq ask | |
30460aeb | 279 | will cause ssh |
7e82606e | 280 | to listen for control connections, but require confirmation using the |
281 | .Ev SSH_ASKPASS | |
282 | program before they are accepted (see | |
283 | .Xr ssh-add 1 | |
284 | for details). | |
2ce0bfe4 | 285 | If the |
286 | .Cm ControlPath | |
30460aeb | 287 | cannot be opened, |
288 | ssh will continue without connecting to a master instance. | |
2ce0bfe4 | 289 | .Pp |
290 | X11 and | |
291 | .Xr ssh-agent 1 | |
292 | forwarding is supported over these multiplexed connections, however the | |
08822d99 | 293 | display and agent forwarded will be the one belonging to the master |
2ce0bfe4 | 294 | connection i.e. it is not possible to forward multiple displays or agents. |
295 | .Pp | |
296 | Two additional options allow for opportunistic multiplexing: try to use a | |
297 | master connection but fall back to creating a new one if one does not already | |
298 | exist. | |
299 | These options are: | |
300 | .Dq auto | |
301 | and | |
302 | .Dq autoask . | |
303 | The latter requires confirmation like the | |
304 | .Dq ask | |
305 | option. | |
7e82606e | 306 | .It Cm ControlPath |
2ce0bfe4 | 307 | Specify the path to the control socket used for connection sharing as described |
308 | in the | |
7e82606e | 309 | .Cm ControlMaster |
2ce0bfe4 | 310 | section above or the string |
311 | .Dq none | |
312 | to disable connection sharing. | |
313 | In the path, | |
30460aeb | 314 | .Ql %l |
315 | will be substituted by the local host name, | |
2ce0bfe4 | 316 | .Ql %h |
317 | will be substituted by the target host name, | |
318 | .Ql %p | |
30460aeb | 319 | the port, and |
2ce0bfe4 | 320 | .Ql %r |
321 | by the remote login username. | |
322 | It is recommended that any | |
323 | .Cm ControlPath | |
324 | used for opportunistic connection sharing include | |
30460aeb | 325 | at least %h, %p, and %r. |
2ce0bfe4 | 326 | This ensures that shared connections are uniquely identified. |
884dc78b | 327 | .It Cm DynamicForward |
08822d99 | 328 | Specifies that a TCP port on the local machine be forwarded |
884dc78b | 329 | over the secure channel, and the application |
330 | protocol is then used to determine where to connect to from the | |
bfe49944 | 331 | remote machine. |
08822d99 | 332 | .Pp |
333 | The argument must be | |
334 | .Sm off | |
335 | .Oo Ar bind_address : Oc Ar port . | |
336 | .Sm on | |
337 | IPv6 addresses can be specified by enclosing addresses in square brackets or | |
338 | by using an alternative syntax: | |
339 | .Oo Ar bind_address Ns / Oc Ns Ar port . | |
340 | By default, the local port is bound in accordance with the | |
341 | .Cm GatewayPorts | |
342 | setting. | |
343 | However, an explicit | |
344 | .Ar bind_address | |
345 | may be used to bind the connection to a specific address. | |
346 | The | |
347 | .Ar bind_address | |
348 | of | |
349 | .Dq localhost | |
350 | indicates that the listening port be bound for local use only, while an | |
351 | empty address or | |
352 | .Sq * | |
353 | indicates that the port should be available from all interfaces. | |
354 | .Pp | |
7cac2b65 | 355 | Currently the SOCKS4 and SOCKS5 protocols are supported, and |
30460aeb | 356 | .Xr ssh 1 |
7cac2b65 | 357 | will act as a SOCKS server. |
884dc78b | 358 | Multiple forwardings may be specified, and |
bfe49944 | 359 | additional forwardings can be given on the command line. |
360 | Only the superuser can forward privileged ports. | |
7cac2b65 | 361 | .It Cm EnableSSHKeysign |
362 | Setting this option to | |
363 | .Dq yes | |
364 | in the global client configuration file | |
365 | .Pa /etc/ssh/ssh_config | |
366 | enables the use of the helper program | |
367 | .Xr ssh-keysign 8 | |
368 | during | |
369 | .Cm HostbasedAuthentication . | |
370 | The argument must be | |
371 | .Dq yes | |
372 | or | |
373 | .Dq no . | |
374 | The default is | |
375 | .Dq no . | |
540d72c3 | 376 | This option should be placed in the non-hostspecific section. |
7cac2b65 | 377 | See |
378 | .Xr ssh-keysign 8 | |
379 | for more information. | |
884dc78b | 380 | .It Cm EscapeChar |
381 | Sets the escape character (default: | |
382 | .Ql ~ ) . | |
383 | The escape character can also | |
384 | be set on the command line. | |
385 | The argument should be a single character, | |
386 | .Ql ^ | |
387 | followed by a letter, or | |
388 | .Dq none | |
389 | to disable the escape | |
390 | character entirely (making the connection transparent for binary | |
391 | data). | |
30460aeb | 392 | .It Cm ExitOnForwardFailure |
393 | Specifies whether | |
394 | .Xr ssh 1 | |
395 | should terminate the connection if it cannot set up all requested | |
fa0f0f45 | 396 | dynamic, tunnel, local, and remote port forwardings. |
30460aeb | 397 | The argument must be |
398 | .Dq yes | |
399 | or | |
400 | .Dq no . | |
401 | The default is | |
402 | .Dq no . | |
884dc78b | 403 | .It Cm ForwardAgent |
404 | Specifies whether the connection to the authentication agent (if any) | |
405 | will be forwarded to the remote machine. | |
406 | The argument must be | |
407 | .Dq yes | |
408 | or | |
409 | .Dq no . | |
410 | The default is | |
411 | .Dq no . | |
d03f4262 | 412 | .Pp |
bfe49944 | 413 | Agent forwarding should be enabled with caution. |
414 | Users with the ability to bypass file permissions on the remote host | |
415 | (for the agent's Unix-domain socket) | |
416 | can access the local agent through the forwarded connection. | |
417 | An attacker cannot obtain key material from the agent, | |
d03f4262 | 418 | however they can perform operations on the keys that enable them to |
419 | authenticate using the identities loaded into the agent. | |
884dc78b | 420 | .It Cm ForwardX11 |
421 | Specifies whether X11 connections will be automatically redirected | |
422 | over the secure channel and | |
423 | .Ev DISPLAY | |
424 | set. | |
425 | The argument must be | |
426 | .Dq yes | |
427 | or | |
428 | .Dq no . | |
429 | The default is | |
430 | .Dq no . | |
d03f4262 | 431 | .Pp |
bfe49944 | 432 | X11 forwarding should be enabled with caution. |
433 | Users with the ability to bypass file permissions on the remote host | |
540d72c3 | 434 | (for the user's X11 authorization database) |
bfe49944 | 435 | can access the local X11 display through the forwarded connection. |
540d72c3 | 436 | An attacker may then be able to perform activities such as keystroke monitoring |
437 | if the | |
438 | .Cm ForwardX11Trusted | |
439 | option is also enabled. | |
440 | .It Cm ForwardX11Trusted | |
7e82606e | 441 | If this option is set to |
30460aeb | 442 | .Dq yes , |
443 | remote X11 clients will have full access to the original X11 display. | |
dfddba3d | 444 | .Pp |
540d72c3 | 445 | If this option is set to |
30460aeb | 446 | .Dq no , |
447 | remote X11 clients will be considered untrusted and prevented | |
540d72c3 | 448 | from stealing or tampering with data belonging to trusted X11 |
449 | clients. | |
dfddba3d | 450 | Furthermore, the |
451 | .Xr xauth 1 | |
452 | token used for the session will be set to expire after 20 minutes. | |
453 | Remote clients will be refused access after this time. | |
540d72c3 | 454 | .Pp |
455 | The default is | |
456 | .Dq no . | |
457 | .Pp | |
458 | See the X11 SECURITY extension specification for full details on | |
459 | the restrictions imposed on untrusted clients. | |
884dc78b | 460 | .It Cm GatewayPorts |
461 | Specifies whether remote hosts are allowed to connect to local | |
462 | forwarded ports. | |
463 | By default, | |
30460aeb | 464 | .Xr ssh 1 |
bfe49944 | 465 | binds local port forwardings to the loopback address. |
466 | This prevents other remote hosts from connecting to forwarded ports. | |
884dc78b | 467 | .Cm GatewayPorts |
30460aeb | 468 | can be used to specify that ssh |
884dc78b | 469 | should bind local port forwardings to the wildcard address, |
470 | thus allowing remote hosts to connect to forwarded ports. | |
471 | The argument must be | |
472 | .Dq yes | |
473 | or | |
474 | .Dq no . | |
475 | The default is | |
476 | .Dq no . | |
477 | .It Cm GlobalKnownHostsFile | |
478 | Specifies a file to use for the global | |
479 | host key database instead of | |
480 | .Pa /etc/ssh/ssh_known_hosts . | |
7cac2b65 | 481 | .It Cm GSSAPIAuthentication |
540d72c3 | 482 | Specifies whether user authentication based on GSSAPI is allowed. |
f713db99 | 483 | The default is |
44a053a3 | 484 | .Dq yes . |
85740ad2 | 485 | Note that this option applies to protocol version 2 only. |
7cac2b65 | 486 | .It Cm GSSAPIKeyExchange |
7a056ed1 | 487 | Specifies whether key exchange based on GSSAPI may be used. When using |
488 | GSSAPI key exchange the server need not have a host key. | |
489 | The default is | |
490 | .Dq yes . | |
85740ad2 | 491 | Note that this option applies to protocol version 2 only. |
7cac2b65 | 492 | .It Cm GSSAPIDelegateCredentials |
85740ad2 | 493 | Forward (delegate) credentials to the server. |
44a053a3 | 494 | The default is |
495 | .Dq yes . | |
85740ad2 | 496 | Note that this option applies to protocol version 2 only. |
fe4ad273 | 497 | .It Cm GSSAPITrustDns |
498 | Set to | |
f713db99 | 499 | .Dq yes |
500 | to indicate that the DNS is trusted to securely canonicalize | |
fe4ad273 | 501 | the name of the host being connected to. If |
9c0efabd | 502 | .Dq no , |
f713db99 | 503 | the hostname entered on the |
fe4ad273 | 504 | command line will be passed untouched to the GSSAPI library. |
505 | The default is | |
506 | .Dq yes . | |
f713db99 | 507 | This option only applies to protocol version 2 connections using GSSAPI. |
dfddba3d | 508 | .It Cm HashKnownHosts |
509 | Indicates that | |
30460aeb | 510 | .Xr ssh 1 |
dfddba3d | 511 | should hash host names and addresses when they are added to |
2ce0bfe4 | 512 | .Pa ~/.ssh/known_hosts . |
dfddba3d | 513 | These hashed names may be used normally by |
30460aeb | 514 | .Xr ssh 1 |
dfddba3d | 515 | and |
30460aeb | 516 | .Xr sshd 8 , |
dfddba3d | 517 | but they do not reveal identifying information should the file's contents |
518 | be disclosed. | |
519 | The default is | |
520 | .Dq no . | |
30460aeb | 521 | Note that existing names and addresses in known hosts files |
522 | will not be converted automatically, | |
523 | but may be manually hashed using | |
dfddba3d | 524 | .Xr ssh-keygen 1 . |
884dc78b | 525 | .It Cm HostbasedAuthentication |
526 | Specifies whether to try rhosts based authentication with public key | |
527 | authentication. | |
528 | The argument must be | |
529 | .Dq yes | |
530 | or | |
531 | .Dq no . | |
532 | The default is | |
533 | .Dq no . | |
534 | This option applies to protocol version 2 only and | |
535 | is similar to | |
536 | .Cm RhostsRSAAuthentication . | |
537 | .It Cm HostKeyAlgorithms | |
538 | Specifies the protocol version 2 host key algorithms | |
539 | that the client wants to use in order of preference. | |
540 | The default for this option is: | |
541 | .Dq ssh-rsa,ssh-dss . | |
542 | .It Cm HostKeyAlias | |
543 | Specifies an alias that should be used instead of the | |
544 | real host name when looking up or saving the host key | |
545 | in the host key database files. | |
30460aeb | 546 | This option is useful for tunneling SSH connections |
884dc78b | 547 | or for multiple servers running on a single host. |
548 | .It Cm HostName | |
549 | Specifies the real host name to log into. | |
550 | This can be used to specify nicknames or abbreviations for hosts. | |
30460aeb | 551 | The default is the name given on the command line. |
884dc78b | 552 | Numeric IP addresses are also permitted (both on the command line and in |
553 | .Cm HostName | |
554 | specifications). | |
12a403af | 555 | .It Cm IdentitiesOnly |
556 | Specifies that | |
30460aeb | 557 | .Xr ssh 1 |
12a403af | 558 | should only use the authentication identity files configured in the |
7e82606e | 559 | .Nm |
12a403af | 560 | files, |
30460aeb | 561 | even if |
562 | .Xr ssh-agent 1 | |
12a403af | 563 | offers more identities. |
564 | The argument to this keyword must be | |
565 | .Dq yes | |
566 | or | |
567 | .Dq no . | |
30460aeb | 568 | This option is intended for situations where ssh-agent |
12a403af | 569 | offers many different identities. |
570 | The default is | |
571 | .Dq no . | |
08822d99 | 572 | .It Cm IdentityFile |
573 | Specifies a file from which the user's RSA or DSA authentication identity | |
574 | is read. | |
575 | The default is | |
576 | .Pa ~/.ssh/identity | |
577 | for protocol version 1, and | |
578 | .Pa ~/.ssh/id_rsa | |
579 | and | |
580 | .Pa ~/.ssh/id_dsa | |
581 | for protocol version 2. | |
582 | Additionally, any identities represented by the authentication agent | |
583 | will be used for authentication. | |
30460aeb | 584 | .Pp |
08822d99 | 585 | The file name may use the tilde |
30460aeb | 586 | syntax to refer to a user's home directory or one of the following |
587 | escape characters: | |
588 | .Ql %d | |
589 | (local user's home directory), | |
590 | .Ql %u | |
591 | (local user name), | |
592 | .Ql %l | |
593 | (local host name), | |
594 | .Ql %h | |
595 | (remote host name) or | |
596 | .Ql %r | |
597 | (remote user name). | |
598 | .Pp | |
08822d99 | 599 | It is possible to have |
600 | multiple identity files specified in configuration files; all these | |
601 | identities will be tried in sequence. | |
dfddba3d | 602 | .It Cm KbdInteractiveDevices |
603 | Specifies the list of methods to use in keyboard-interactive authentication. | |
604 | Multiple method names must be comma-separated. | |
605 | The default is to use the server specified list. | |
30460aeb | 606 | The methods available vary depending on what the server supports. |
607 | For an OpenSSH server, | |
608 | it may be zero or more of: | |
609 | .Dq bsdauth , | |
610 | .Dq pam , | |
611 | and | |
612 | .Dq skey . | |
08822d99 | 613 | .It Cm LocalCommand |
614 | Specifies a command to execute on the local machine after successfully | |
615 | connecting to the server. | |
616 | The command string extends to the end of the line, and is executed with | |
617 | .Pa /bin/sh . | |
618 | This directive is ignored unless | |
619 | .Cm PermitLocalCommand | |
620 | has been enabled. | |
884dc78b | 621 | .It Cm LocalForward |
08822d99 | 622 | Specifies that a TCP port on the local machine be forwarded over |
884dc78b | 623 | the secure channel to the specified host and port from the remote machine. |
8b32eddc | 624 | The first argument must be |
dfddba3d | 625 | .Sm off |
8b32eddc | 626 | .Oo Ar bind_address : Oc Ar port |
dfddba3d | 627 | .Sm on |
8b32eddc | 628 | and the second argument must be |
629 | .Ar host : Ns Ar hostport . | |
dfddba3d | 630 | IPv6 addresses can be specified by enclosing addresses in square brackets or |
631 | by using an alternative syntax: | |
8b32eddc | 632 | .Oo Ar bind_address Ns / Oc Ns Ar port |
633 | and | |
634 | .Ar host Ns / Ns Ar hostport . | |
dfddba3d | 635 | Multiple forwardings may be specified, and additional forwardings can be |
636 | given on the command line. | |
884dc78b | 637 | Only the superuser can forward privileged ports. |
dfddba3d | 638 | By default, the local port is bound in accordance with the |
639 | .Cm GatewayPorts | |
640 | setting. | |
641 | However, an explicit | |
642 | .Ar bind_address | |
643 | may be used to bind the connection to a specific address. | |
644 | The | |
645 | .Ar bind_address | |
646 | of | |
647 | .Dq localhost | |
648 | indicates that the listening port be bound for local use only, while an | |
649 | empty address or | |
650 | .Sq * | |
651 | indicates that the port should be available from all interfaces. | |
884dc78b | 652 | .It Cm LogLevel |
653 | Gives the verbosity level that is used when logging messages from | |
30460aeb | 654 | .Xr ssh 1 . |
884dc78b | 655 | The possible values are: |
30460aeb | 656 | QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. |
bfe49944 | 657 | The default is INFO. |
658 | DEBUG and DEBUG1 are equivalent. | |
659 | DEBUG2 and DEBUG3 each specify higher levels of verbose output. | |
884dc78b | 660 | .It Cm MACs |
661 | Specifies the MAC (message authentication code) algorithms | |
662 | in order of preference. | |
663 | The MAC algorithm is used in protocol version 2 | |
664 | for data integrity protection. | |
665 | Multiple algorithms must be comma-separated. | |
30460aeb | 666 | The default is: |
fa0f0f45 | 667 | .Bd -literal -offset indent |
668 | hmac-md5,hmac-sha1,umac-64@openssh.com, | |
669 | hmac-ripemd160,hmac-sha1-96,hmac-md5-96 | |
670 | .Ed | |
884dc78b | 671 | .It Cm NoHostAuthenticationForLocalhost |
672 | This option can be used if the home directory is shared across machines. | |
673 | In this case localhost will refer to a different machine on each of | |
674 | the machines and the user will get many warnings about changed host keys. | |
675 | However, this option disables host authentication for localhost. | |
676 | The argument to this keyword must be | |
677 | .Dq yes | |
678 | or | |
679 | .Dq no . | |
680 | The default is to check the host key for localhost. | |
681 | .It Cm NumberOfPasswordPrompts | |
682 | Specifies the number of password prompts before giving up. | |
683 | The argument to this keyword must be an integer. | |
30460aeb | 684 | The default is 3. |
884dc78b | 685 | .It Cm PasswordAuthentication |
686 | Specifies whether to use password authentication. | |
687 | The argument to this keyword must be | |
688 | .Dq yes | |
689 | or | |
690 | .Dq no . | |
691 | The default is | |
692 | .Dq yes . | |
08822d99 | 693 | .It Cm PermitLocalCommand |
694 | Allow local command execution via the | |
695 | .Ic LocalCommand | |
696 | option or using the | |
697 | .Ic !\& Ns Ar command | |
698 | escape sequence in | |
699 | .Xr ssh 1 . | |
700 | The argument must be | |
701 | .Dq yes | |
702 | or | |
703 | .Dq no . | |
704 | The default is | |
705 | .Dq no . | |
884dc78b | 706 | .It Cm Port |
707 | Specifies the port number to connect on the remote host. | |
30460aeb | 708 | The default is 22. |
884dc78b | 709 | .It Cm PreferredAuthentications |
710 | Specifies the order in which the client should try protocol 2 | |
7cac2b65 | 711 | authentication methods. |
8b32eddc | 712 | This allows a client to prefer one method (e.g.\& |
884dc78b | 713 | .Cm keyboard-interactive ) |
8b32eddc | 714 | over another method (e.g.\& |
884dc78b | 715 | .Cm password ) |
716 | The default for this option is: | |
30460aeb | 717 | .Do gssapi-keyex , |
718 | external-keyx, | |
719 | gssapi-with-mic, | |
720 | hostbased, | |
721 | publickey, | |
722 | keyboard-interactive, | |
723 | password | |
724 | .Dc . | |
884dc78b | 725 | .It Cm Protocol |
726 | Specifies the protocol versions | |
30460aeb | 727 | .Xr ssh 1 |
884dc78b | 728 | should support in order of preference. |
729 | The possible values are | |
30460aeb | 730 | .Sq 1 |
884dc78b | 731 | and |
30460aeb | 732 | .Sq 2 . |
884dc78b | 733 | Multiple versions must be comma-separated. |
734 | The default is | |
735 | .Dq 2,1 . | |
30460aeb | 736 | This means that ssh |
884dc78b | 737 | tries version 2 and falls back to version 1 |
738 | if version 2 is not available. | |
739 | .It Cm ProxyCommand | |
740 | Specifies the command to use to connect to the server. | |
741 | The command | |
742 | string extends to the end of the line, and is executed with | |
743 | .Pa /bin/sh . | |
744 | In the command string, | |
745 | .Ql %h | |
746 | will be substituted by the host name to | |
747 | connect and | |
748 | .Ql %p | |
749 | by the port. | |
750 | The command can be basically anything, | |
751 | and should read from its standard input and write to its standard output. | |
752 | It should eventually connect an | |
753 | .Xr sshd 8 | |
754 | server running on some machine, or execute | |
755 | .Ic sshd -i | |
756 | somewhere. | |
757 | Host key management will be done using the | |
758 | HostName of the host being connected (defaulting to the name typed by | |
759 | the user). | |
bfe49944 | 760 | Setting the command to |
761 | .Dq none | |
762 | disables this option entirely. | |
884dc78b | 763 | Note that |
764 | .Cm CheckHostIP | |
765 | is not available for connects with a proxy command. | |
766 | .Pp | |
2ce0bfe4 | 767 | This directive is useful in conjunction with |
768 | .Xr nc 1 | |
769 | and its proxy support. | |
770 | For example, the following directive would connect via an HTTP proxy at | |
771 | 192.0.2.0: | |
772 | .Bd -literal -offset 3n | |
773 | ProxyCommand /usr/bin/nc -X connect -x 192.0.2.0:8080 %h %p | |
774 | .Ed | |
884dc78b | 775 | .It Cm PubkeyAuthentication |
776 | Specifies whether to try public key authentication. | |
777 | The argument to this keyword must be | |
778 | .Dq yes | |
779 | or | |
780 | .Dq no . | |
781 | The default is | |
782 | .Dq yes . | |
783 | This option applies to protocol version 2 only. | |
08822d99 | 784 | .It Cm RekeyLimit |
785 | Specifies the maximum amount of data that may be transmitted before the | |
786 | session key is renegotiated. | |
787 | The argument is the number of bytes, with an optional suffix of | |
788 | .Sq K , | |
789 | .Sq M , | |
790 | or | |
791 | .Sq G | |
792 | to indicate Kilobytes, Megabytes, or Gigabytes, respectively. | |
793 | The default is between | |
30460aeb | 794 | .Sq 1G |
08822d99 | 795 | and |
30460aeb | 796 | .Sq 4G , |
08822d99 | 797 | depending on the cipher. |
798 | This option applies to protocol version 2 only. | |
884dc78b | 799 | .It Cm RemoteForward |
08822d99 | 800 | Specifies that a TCP port on the remote machine be forwarded over |
884dc78b | 801 | the secure channel to the specified host and port from the local machine. |
8b32eddc | 802 | The first argument must be |
dfddba3d | 803 | .Sm off |
8b32eddc | 804 | .Oo Ar bind_address : Oc Ar port |
dfddba3d | 805 | .Sm on |
8b32eddc | 806 | and the second argument must be |
807 | .Ar host : Ns Ar hostport . | |
808 | IPv6 addresses can be specified by enclosing addresses in square brackets | |
809 | or by using an alternative syntax: | |
810 | .Oo Ar bind_address Ns / Oc Ns Ar port | |
811 | and | |
812 | .Ar host Ns / Ns Ar hostport . | |
884dc78b | 813 | Multiple forwardings may be specified, and additional |
814 | forwardings can be given on the command line. | |
815 | Only the superuser can forward privileged ports. | |
dfddba3d | 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 | |
828 | will only succeed if the server's | |
829 | .Cm GatewayPorts | |
830 | option is enabled (see | |
831 | .Xr sshd_config 5 ) . | |
884dc78b | 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 | |
30460aeb | 842 | .Xr ssh 1 |
884dc78b | 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. | |
7e82606e | 856 | .It Cm SendEnv |
857 | Specifies what variables from the local | |
858 | .Xr environ 7 | |
859 | should be sent to the server. | |
30460aeb | 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 | |
7e82606e | 862 | accept these environment variables. |
863 | Refer to | |
864 | .Cm AcceptEnv | |
865 | in | |
866 | .Xr sshd_config 5 | |
867 | for how to configure the server. | |
30460aeb | 868 | Variables are specified by name, which may contain wildcard characters. |
7e82606e | 869 | Multiple environment variables may be separated by whitespace or spread |
870 | across multiple | |
871 | .Cm SendEnv | |
872 | directives. | |
873 | The default is not to send any environment variables. | |
30460aeb | 874 | .Pp |
875 | See | |
876 | .Sx PATTERNS | |
877 | for more information on patterns. | |
540d72c3 | 878 | .It Cm ServerAliveCountMax |
08822d99 | 879 | Sets the number of server alive messages (see below) which may be |
540d72c3 | 880 | sent without |
30460aeb | 881 | .Xr ssh 1 |
540d72c3 | 882 | receiving any messages back from the server. |
883 | If this threshold is reached while server alive messages are being sent, | |
30460aeb | 884 | ssh will disconnect from the server, terminating the session. |
540d72c3 | 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 | |
30460aeb | 900 | (see below) is set to 15 and |
540d72c3 | 901 | .Cm ServerAliveCountMax |
30460aeb | 902 | is left at the default, if the server becomes unresponsive, |
903 | ssh will disconnect after approximately 45 seconds. | |
904 | This option applies to protocol version 2 only. | |
08822d99 | 905 | .It Cm ServerAliveInterval |
906 | Sets a timeout interval in seconds after which if no data has been received | |
907 | from the server, | |
30460aeb | 908 | .Xr ssh 1 |
08822d99 | 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. | |
884dc78b | 914 | .It Cm SmartcardDevice |
7cac2b65 | 915 | Specifies which smartcard device to use. |
916 | The argument to this keyword is the device | |
30460aeb | 917 | .Xr ssh 1 |
884dc78b | 918 | should use to communicate with a smartcard used for storing the user's |
7cac2b65 | 919 | private RSA key. |
920 | By default, no device is specified and smartcard support is not activated. | |
884dc78b | 921 | .It Cm StrictHostKeyChecking |
922 | If this flag is set to | |
923 | .Dq yes , | |
30460aeb | 924 | .Xr ssh 1 |
884dc78b | 925 | will never automatically add host keys to the |
2ce0bfe4 | 926 | .Pa ~/.ssh/known_hosts |
884dc78b | 927 | file, and refuses to connect to hosts whose host key has changed. |
928 | This provides maximum protection against trojan horse attacks, | |
30460aeb | 929 | though it can be annoying when the |
884dc78b | 930 | .Pa /etc/ssh/ssh_known_hosts |
30460aeb | 931 | file is poorly maintained or when connections to new hosts are |
884dc78b | 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 , | |
30460aeb | 937 | ssh will automatically add new host keys to the |
884dc78b | 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 | |
30460aeb | 944 | ssh will refuse to connect to hosts whose host key has changed. |
884dc78b | 945 | The host keys of |
946 | known hosts will be verified automatically in all cases. | |
947 | The argument must be | |
948 | .Dq yes , | |
30460aeb | 949 | .Dq no , |
884dc78b | 950 | or |
951 | .Dq ask . | |
952 | The default is | |
953 | .Dq ask . | |
540d72c3 | 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 . | |
08822d99 | 971 | .It Cm Tunnel |
30460aeb | 972 | Request |
08822d99 | 973 | .Xr tun 4 |
974 | device forwarding between the client and the server. | |
08822d99 | 975 | The argument must be |
976 | .Dq yes , | |
30460aeb | 977 | .Dq point-to-point |
978 | (layer 3), | |
08822d99 | 979 | .Dq ethernet |
30460aeb | 980 | (layer 2), |
08822d99 | 981 | or |
982 | .Dq no . | |
30460aeb | 983 | Specifying |
984 | .Dq yes | |
985 | requests the default tunnel mode, which is | |
986 | .Dq point-to-point . | |
08822d99 | 987 | The default is |
988 | .Dq no . | |
989 | .It Cm TunnelDevice | |
30460aeb | 990 | Specifies the |
08822d99 | 991 | .Xr tun 4 |
30460aeb | 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 . | |
884dc78b | 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 . | |
d03f4262 | 1018 | If set to |
30460aeb | 1019 | .Dq yes , |
1020 | .Xr ssh 1 | |
d03f4262 | 1021 | must be setuid root. |
884dc78b | 1022 | Note that this option must be set to |
1023 | .Dq yes | |
7cac2b65 | 1024 | for |
884dc78b | 1025 | .Cm RhostsRSAAuthentication |
7cac2b65 | 1026 | with older servers. |
884dc78b | 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 | |
2ce0bfe4 | 1035 | .Pa ~/.ssh/known_hosts . |
7cac2b65 | 1036 | .It Cm VerifyHostKeyDNS |
1037 | Specifies whether to verify the remote key using DNS and SSHFP resource | |
1038 | records. | |
540d72c3 | 1039 | If this option is set to |
1040 | .Dq yes , | |
1041 | the client will implicitly trust keys that match a secure fingerprint | |
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 , | |
30460aeb | 1053 | .Dq no , |
540d72c3 | 1054 | or |
1055 | .Dq ask . | |
7cac2b65 | 1056 | The default is |
1057 | .Dq no . | |
1058 | Note that this option applies to protocol version 2 only. | |
30460aeb | 1059 | .Pp |
1060 | See also | |
1061 | .Sx VERIFYING HOST KEYS | |
1062 | in | |
1063 | .Xr ssh 1 . | |
884dc78b | 1064 | .It Cm XAuthLocation |
d03f4262 | 1065 | Specifies the full pathname of the |
884dc78b | 1066 | .Xr xauth 1 |
1067 | program. | |
1068 | The default is | |
1069 | .Pa /usr/X11R6/bin/xauth . | |
1070 | .El | |
30460aeb | 1071 | .Sh PATTERNS |
1072 | A | |
1073 | .Em pattern | |
1074 | consists of zero or more non-whitespace characters, | |
1075 | .Sq * | |
1076 | (a wildcard that matches zero or more characters), | |
1077 | or | |
1078 | .Sq ?\& | |
1079 | (a wildcard that matches exactly one character). | |
1080 | For example, to specify a set of declarations for any host in the | |
1081 | .Dq .co.uk | |
1082 | set of domains, | |
1083 | the following pattern could be used: | |
1084 | .Pp | |
1085 | .Dl Host *.co.uk | |
1086 | .Pp | |
1087 | The following pattern | |
1088 | would match any host in the 192.168.0.[0-9] network range: | |
1089 | .Pp | |
1090 | .Dl Host 192.168.0.? | |
1091 | .Pp | |
1092 | A | |
1093 | .Em pattern-list | |
1094 | is a comma-separated list of patterns. | |
1095 | Patterns within pattern-lists may be negated | |
1096 | by preceding them with an exclamation mark | |
1097 | .Pq Sq !\& . | |
1098 | For example, | |
1099 | to allow a key to be used from anywhere within an organisation | |
1100 | except from the | |
1101 | .Dq dialup | |
1102 | pool, | |
1103 | the following entry (in authorized_keys) could be used: | |
1104 | .Pp | |
1105 | .Dl from=\&"!*.dialup.example.com,*.example.com\&" | |
884dc78b | 1106 | .Sh FILES |
1107 | .Bl -tag -width Ds | |
2ce0bfe4 | 1108 | .It Pa ~/.ssh/config |
884dc78b | 1109 | This is the per-user configuration file. |
1110 | The format of this file is described above. | |
30460aeb | 1111 | This file is used by the SSH client. |
7e82606e | 1112 | Because of the potential for abuse, this file must have strict permissions: |
1113 | read/write for the user, and not accessible by others. | |
884dc78b | 1114 | .It Pa /etc/ssh/ssh_config |
1115 | Systemwide configuration file. | |
1116 | This file provides defaults for those | |
1117 | values that are not specified in the user's configuration file, and | |
1118 | for those users who do not have a configuration file. | |
1119 | This file must be world-readable. | |
1120 | .El | |
7cac2b65 | 1121 | .Sh SEE ALSO |
1122 | .Xr ssh 1 | |
884dc78b | 1123 | .Sh AUTHORS |
1124 | OpenSSH is a derivative of the original and free | |
1125 | ssh 1.2.12 release by Tatu Ylonen. | |
1126 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, | |
1127 | Theo de Raadt and Dug Song | |
1128 | removed many bugs, re-added newer features and | |
1129 | created OpenSSH. | |
1130 | Markus Friedl contributed the support for SSH | |
1131 | protocol versions 1.5 and 2.0. |