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ff2d7a98 | 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 | .\" | |
2e437378 | 37 | .\" $OpenBSD: ssh_config.5,v 1.97 2006/07/27 08:00:50 jmc Exp $ |
ff2d7a98 | 38 | .Dd September 25, 1999 |
39 | .Dt SSH_CONFIG 5 | |
40 | .Os | |
41 | .Sh NAME | |
42 | .Nm ssh_config | |
43 | .Nd OpenSSH SSH client configuration files | |
44 | .Sh SYNOPSIS | |
45 | .Bl -tag -width Ds -compact | |
34fee935 | 46 | .It Pa ~/.ssh/config |
ff2d7a98 | 47 | .It Pa /etc/ssh/ssh_config |
48 | .El | |
49 | .Sh DESCRIPTION | |
2e437378 | 50 | .Xr ssh 1 |
ff2d7a98 | 51 | obtains configuration data from the following sources in |
52 | the following order: | |
2e437378 | 53 | .Pp |
e54b3d7c | 54 | .Bl -enum -offset indent -compact |
55 | .It | |
56 | command-line options | |
57 | .It | |
ff2d7a98 | 58 | user's configuration file |
34fee935 | 59 | .Pq Pa ~/.ssh/config |
e54b3d7c | 60 | .It |
61 | GSSAPI configuration file | |
62 | .Pq Pa $HOME/.ssh/config.gssapi | |
63 | .It | |
64 | Kerberos configuration file | |
65 | .Pq Pa $HOME/.ssh/config.krb | |
66 | .It | |
e54b3d7c | 67 | system-wide configuration file |
68 | .Pq Pa /etc/ssh/ssh_config | |
ff2d7a98 | 69 | .El |
70 | .Pp | |
71 | For each parameter, the first obtained value | |
72 | will be used. | |
34fee935 | 73 | The configuration files contain sections separated by |
ff2d7a98 | 74 | .Dq Host |
75 | specifications, and that section is only applied for hosts that | |
76 | match one of the patterns given in the specification. | |
77 | The matched host name is the one given on the command line. | |
78 | .Pp | |
79 | Since the first obtained value for each parameter is used, more | |
80 | host-specific declarations should be given near the beginning of the | |
81 | file, and general defaults at the end. | |
82 | .Pp | |
83 | The configuration file has the following format: | |
84 | .Pp | |
85 | Empty lines and lines starting with | |
86 | .Ql # | |
87 | are comments. | |
ff2d7a98 | 88 | Otherwise a line is of the format |
89 | .Dq keyword arguments . | |
90 | Configuration options may be separated by whitespace or | |
91 | optional whitespace and exactly one | |
92 | .Ql = ; | |
93 | the latter format is useful to avoid the need to quote whitespace | |
94 | when specifying configuration options using the | |
95 | .Nm ssh , | |
2e437378 | 96 | .Nm scp , |
ff2d7a98 | 97 | and |
98 | .Nm sftp | |
99 | .Fl o | |
100 | option. | |
2e437378 | 101 | Arguments may optionally be enclosed in double quotes |
102 | .Pq \&" | |
103 | in order to represent arguments containing spaces. | |
ff2d7a98 | 104 | .Pp |
105 | The possible | |
106 | keywords and their meanings are as follows (note that | |
107 | keywords are case-insensitive and arguments are case-sensitive): | |
108 | .Bl -tag -width Ds | |
109 | .It Cm Host | |
110 | Restricts the following declarations (up to the next | |
111 | .Cm Host | |
112 | keyword) to be only for those hosts that match one of the patterns | |
113 | given after the keyword. | |
ff2d7a98 | 114 | A single |
2e437378 | 115 | .Ql * |
ff2d7a98 | 116 | as a pattern can be used to provide global |
117 | defaults for all hosts. | |
118 | The host is the | |
119 | .Ar hostname | |
2e437378 | 120 | argument given on the command line (i.e. the name is not converted to |
ff2d7a98 | 121 | a canonicalized host name before matching). |
2e437378 | 122 | .Pp |
123 | See | |
124 | .Sx PATTERNS | |
125 | for more information on patterns. | |
70791e56 | 126 | .It Cm AddressFamily |
127 | Specifies which address family to use when connecting. | |
128 | Valid arguments are | |
129 | .Dq any , | |
130 | .Dq inet | |
2e437378 | 131 | (use IPv4 only), or |
70791e56 | 132 | .Dq inet6 |
34fee935 | 133 | (use IPv6 only). |
ff2d7a98 | 134 | .It Cm BatchMode |
135 | If set to | |
136 | .Dq yes , | |
137 | passphrase/password querying will be disabled. | |
138 | This option is useful in scripts and other batch jobs where no user | |
139 | is present to supply the password. | |
140 | The argument must be | |
141 | .Dq yes | |
142 | or | |
143 | .Dq no . | |
144 | The default is | |
145 | .Dq no . | |
146 | .It Cm BindAddress | |
34fee935 | 147 | Use the specified address on the local machine as the source address of |
148 | the connection. | |
149 | Only useful on systems with more than one address. | |
ff2d7a98 | 150 | Note that this option does not work if |
151 | .Cm UsePrivilegedPort | |
152 | is set to | |
153 | .Dq yes . | |
154 | .It Cm ChallengeResponseAuthentication | |
2e437378 | 155 | Specifies whether to use challenge-response authentication. |
ff2d7a98 | 156 | The argument to this keyword must be |
157 | .Dq yes | |
158 | or | |
159 | .Dq no . | |
160 | The default is | |
161 | .Dq yes . | |
162 | .It Cm CheckHostIP | |
163 | If this flag is set to | |
164 | .Dq yes , | |
2e437378 | 165 | .Xr ssh 1 |
166 | will additionally check the host IP address in the | |
ff2d7a98 | 167 | .Pa known_hosts |
168 | file. | |
169 | This allows ssh to detect if a host key changed due to DNS spoofing. | |
170 | If the option is set to | |
171 | .Dq no , | |
172 | the check will not be executed. | |
173 | The default is | |
174 | .Dq yes . | |
175 | .It Cm Cipher | |
176 | Specifies the cipher to use for encrypting the session | |
177 | in protocol version 1. | |
178 | Currently, | |
179 | .Dq blowfish , | |
180 | .Dq 3des , | |
181 | and | |
182 | .Dq des | |
183 | are supported. | |
184 | .Ar des | |
185 | is only supported in the | |
2e437378 | 186 | .Xr ssh 1 |
ff2d7a98 | 187 | client for interoperability with legacy protocol 1 implementations |
188 | that do not support the | |
189 | .Ar 3des | |
1c14df9e | 190 | cipher. |
191 | Its use is strongly discouraged due to cryptographic weaknesses. | |
ff2d7a98 | 192 | The default is |
193 | .Dq 3des . | |
194 | .It Cm Ciphers | |
195 | Specifies the ciphers allowed for protocol version 2 | |
196 | in order of preference. | |
197 | Multiple ciphers must be comma-separated. | |
1b56ff3d | 198 | The supported ciphers are |
199 | .Dq 3des-cbc , | |
200 | .Dq aes128-cbc , | |
201 | .Dq aes192-cbc , | |
202 | .Dq aes256-cbc , | |
203 | .Dq aes128-ctr , | |
204 | .Dq aes192-ctr , | |
205 | .Dq aes256-ctr , | |
34fee935 | 206 | .Dq arcfour128 , |
207 | .Dq arcfour256 , | |
1b56ff3d | 208 | .Dq arcfour , |
209 | .Dq blowfish-cbc , | |
210 | and | |
211 | .Dq cast128-cbc . | |
2e437378 | 212 | The default is: |
213 | .Bd -literal -offset 3n | |
214 | aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128, | |
215 | arcfour256,arcfour,aes192-cbc,aes256-cbc,aes128-ctr, | |
216 | aes192-ctr,aes256-ctr | |
ff2d7a98 | 217 | .Ed |
218 | .It Cm ClearAllForwardings | |
2e437378 | 219 | Specifies that all local, remote, and dynamic port forwardings |
ff2d7a98 | 220 | specified in the configuration files or on the command line be |
1c14df9e | 221 | cleared. |
222 | This option is primarily useful when used from the | |
2e437378 | 223 | .Xr ssh 1 |
ff2d7a98 | 224 | command line to clear port forwardings set in |
225 | configuration files, and is automatically set by | |
226 | .Xr scp 1 | |
227 | and | |
228 | .Xr sftp 1 . | |
229 | The argument must be | |
230 | .Dq yes | |
231 | or | |
232 | .Dq no . | |
233 | The default is | |
234 | .Dq no . | |
235 | .It Cm Compression | |
236 | Specifies whether to use compression. | |
237 | The argument must be | |
238 | .Dq yes | |
239 | or | |
240 | .Dq no . | |
241 | The default is | |
242 | .Dq no . | |
243 | .It Cm CompressionLevel | |
244 | Specifies the compression level to use if compression is enabled. | |
245 | The argument must be an integer from 1 (fast) to 9 (slow, best). | |
246 | The default level is 6, which is good for most applications. | |
247 | The meaning of the values is the same as in | |
248 | .Xr gzip 1 . | |
249 | Note that this option applies to protocol version 1 only. | |
250 | .It Cm ConnectionAttempts | |
251 | Specifies the number of tries (one per second) to make before exiting. | |
252 | The argument must be an integer. | |
253 | This may be useful in scripts if the connection sometimes fails. | |
254 | The default is 1. | |
70791e56 | 255 | .It Cm ConnectTimeout |
2e437378 | 256 | Specifies the timeout (in seconds) used when connecting to the |
257 | SSH server, instead of using the default system TCP timeout. | |
70791e56 | 258 | This value is used only when the target is down or really unreachable, |
259 | not when it refuses the connection. | |
1b56ff3d | 260 | .It Cm ControlMaster |
261 | Enables the sharing of multiple sessions over a single network connection. | |
262 | When set to | |
2e437378 | 263 | .Dq yes , |
264 | .Xr ssh 1 | |
1b56ff3d | 265 | will listen for connections on a control socket specified using the |
266 | .Cm ControlPath | |
267 | argument. | |
268 | Additional sessions can connect to this socket using the same | |
269 | .Cm ControlPath | |
270 | with | |
271 | .Cm ControlMaster | |
272 | set to | |
273 | .Dq no | |
274 | (the default). | |
e00da40d | 275 | These sessions will try to reuse the master instance's network connection |
276 | rather than initiating new ones, but will fall back to connecting normally | |
277 | if the control socket does not exist, or is not listening. | |
278 | .Pp | |
1b56ff3d | 279 | Setting this to |
280 | .Dq ask | |
2e437378 | 281 | will cause ssh |
1b56ff3d | 282 | to listen for control connections, but require confirmation using the |
283 | .Ev SSH_ASKPASS | |
284 | program before they are accepted (see | |
285 | .Xr ssh-add 1 | |
286 | for details). | |
34fee935 | 287 | If the |
288 | .Cm ControlPath | |
2e437378 | 289 | cannot be opened, |
290 | ssh will continue without connecting to a master instance. | |
34fee935 | 291 | .Pp |
292 | X11 and | |
293 | .Xr ssh-agent 1 | |
294 | forwarding is supported over these multiplexed connections, however the | |
e00da40d | 295 | display and agent forwarded will be the one belonging to the master |
34fee935 | 296 | connection i.e. it is not possible to forward multiple displays or agents. |
297 | .Pp | |
298 | Two additional options allow for opportunistic multiplexing: try to use a | |
299 | master connection but fall back to creating a new one if one does not already | |
300 | exist. | |
301 | These options are: | |
302 | .Dq auto | |
303 | and | |
304 | .Dq autoask . | |
305 | The latter requires confirmation like the | |
306 | .Dq ask | |
307 | option. | |
1b56ff3d | 308 | .It Cm ControlPath |
34fee935 | 309 | Specify the path to the control socket used for connection sharing as described |
310 | in the | |
1b56ff3d | 311 | .Cm ControlMaster |
34fee935 | 312 | section above or the string |
313 | .Dq none | |
314 | to disable connection sharing. | |
315 | In the path, | |
2e437378 | 316 | .Ql %l |
317 | will be substituted by the local host name, | |
34fee935 | 318 | .Ql %h |
319 | will be substituted by the target host name, | |
320 | .Ql %p | |
2e437378 | 321 | the port, and |
34fee935 | 322 | .Ql %r |
323 | by the remote login username. | |
324 | It is recommended that any | |
325 | .Cm ControlPath | |
326 | used for opportunistic connection sharing include | |
2e437378 | 327 | at least %h, %p, and %r. |
34fee935 | 328 | This ensures that shared connections are uniquely identified. |
ff2d7a98 | 329 | .It Cm DynamicForward |
e00da40d | 330 | Specifies that a TCP port on the local machine be forwarded |
ff2d7a98 | 331 | over the secure channel, and the application |
332 | protocol is then used to determine where to connect to from the | |
1c14df9e | 333 | remote machine. |
e00da40d | 334 | .Pp |
335 | The argument must be | |
336 | .Sm off | |
337 | .Oo Ar bind_address : Oc Ar port . | |
338 | .Sm on | |
339 | IPv6 addresses can be specified by enclosing addresses in square brackets or | |
340 | by using an alternative syntax: | |
341 | .Oo Ar bind_address Ns / Oc Ns Ar port . | |
342 | By default, the local port is bound in accordance with the | |
343 | .Cm GatewayPorts | |
344 | setting. | |
345 | However, an explicit | |
346 | .Ar bind_address | |
347 | may be used to bind the connection to a specific address. | |
348 | The | |
349 | .Ar bind_address | |
350 | of | |
351 | .Dq localhost | |
352 | indicates that the listening port be bound for local use only, while an | |
353 | empty address or | |
354 | .Sq * | |
355 | indicates that the port should be available from all interfaces. | |
356 | .Pp | |
70791e56 | 357 | Currently the SOCKS4 and SOCKS5 protocols are supported, and |
2e437378 | 358 | .Xr ssh 1 |
70791e56 | 359 | will act as a SOCKS server. |
ff2d7a98 | 360 | Multiple forwardings may be specified, and |
1c14df9e | 361 | additional forwardings can be given on the command line. |
362 | Only the superuser can forward privileged ports. | |
70791e56 | 363 | .It Cm EnableSSHKeysign |
364 | Setting this option to | |
365 | .Dq yes | |
366 | in the global client configuration file | |
367 | .Pa /etc/ssh/ssh_config | |
368 | enables the use of the helper program | |
369 | .Xr ssh-keysign 8 | |
370 | during | |
371 | .Cm HostbasedAuthentication . | |
372 | The argument must be | |
373 | .Dq yes | |
374 | or | |
375 | .Dq no . | |
376 | The default is | |
377 | .Dq no . | |
416fd2a8 | 378 | This option should be placed in the non-hostspecific section. |
70791e56 | 379 | See |
380 | .Xr ssh-keysign 8 | |
381 | for more information. | |
ff2d7a98 | 382 | .It Cm EscapeChar |
383 | Sets the escape character (default: | |
384 | .Ql ~ ) . | |
385 | The escape character can also | |
386 | be set on the command line. | |
387 | The argument should be a single character, | |
388 | .Ql ^ | |
389 | followed by a letter, or | |
390 | .Dq none | |
391 | to disable the escape | |
392 | character entirely (making the connection transparent for binary | |
393 | data). | |
2e437378 | 394 | .It Cm ExitOnForwardFailure |
395 | Specifies whether | |
396 | .Xr ssh 1 | |
397 | should terminate the connection if it cannot set up all requested | |
398 | dynamic, local, and remote port forwardings. | |
399 | The argument must be | |
400 | .Dq yes | |
401 | or | |
402 | .Dq no . | |
403 | The default is | |
404 | .Dq no . | |
ff2d7a98 | 405 | .It Cm ForwardAgent |
406 | Specifies whether the connection to the authentication agent (if any) | |
407 | will be forwarded to the remote machine. | |
408 | The argument must be | |
409 | .Dq yes | |
410 | or | |
411 | .Dq no . | |
412 | The default is | |
413 | .Dq no . | |
e54b3d7c | 414 | .Pp |
1c14df9e | 415 | Agent forwarding should be enabled with caution. |
416 | Users with the ability to bypass file permissions on the remote host | |
417 | (for the agent's Unix-domain socket) | |
418 | can access the local agent through the forwarded connection. | |
419 | An attacker cannot obtain key material from the agent, | |
e54b3d7c | 420 | however they can perform operations on the keys that enable them to |
421 | authenticate using the identities loaded into the agent. | |
ff2d7a98 | 422 | .It Cm ForwardX11 |
423 | Specifies whether X11 connections will be automatically redirected | |
424 | over the secure channel and | |
425 | .Ev DISPLAY | |
426 | set. | |
427 | The argument must be | |
428 | .Dq yes | |
429 | or | |
430 | .Dq no . | |
431 | The default is | |
432 | .Dq no . | |
e54b3d7c | 433 | .Pp |
1c14df9e | 434 | X11 forwarding should be enabled with caution. |
435 | Users with the ability to bypass file permissions on the remote host | |
416fd2a8 | 436 | (for the user's X11 authorization database) |
1c14df9e | 437 | can access the local X11 display through the forwarded connection. |
416fd2a8 | 438 | An attacker may then be able to perform activities such as keystroke monitoring |
439 | if the | |
440 | .Cm ForwardX11Trusted | |
441 | option is also enabled. | |
442 | .It Cm ForwardX11Trusted | |
1b56ff3d | 443 | If this option is set to |
2e437378 | 444 | .Dq yes , |
445 | remote X11 clients will have full access to the original X11 display. | |
34fee935 | 446 | .Pp |
416fd2a8 | 447 | If this option is set to |
2e437378 | 448 | .Dq no , |
449 | remote X11 clients will be considered untrusted and prevented | |
416fd2a8 | 450 | from stealing or tampering with data belonging to trusted X11 |
451 | clients. | |
34fee935 | 452 | Furthermore, the |
453 | .Xr xauth 1 | |
454 | token used for the session will be set to expire after 20 minutes. | |
455 | Remote clients will be refused access after this time. | |
416fd2a8 | 456 | .Pp |
457 | The default is | |
458 | .Dq no . | |
459 | .Pp | |
460 | See the X11 SECURITY extension specification for full details on | |
461 | the restrictions imposed on untrusted clients. | |
ff2d7a98 | 462 | .It Cm GatewayPorts |
463 | Specifies whether remote hosts are allowed to connect to local | |
464 | forwarded ports. | |
465 | By default, | |
2e437378 | 466 | .Xr ssh 1 |
1c14df9e | 467 | binds local port forwardings to the loopback address. |
468 | This prevents other remote hosts from connecting to forwarded ports. | |
ff2d7a98 | 469 | .Cm GatewayPorts |
2e437378 | 470 | can be used to specify that ssh |
ff2d7a98 | 471 | should bind local port forwardings to the wildcard address, |
472 | thus allowing remote hosts to connect to forwarded ports. | |
473 | The argument must be | |
474 | .Dq yes | |
475 | or | |
476 | .Dq no . | |
477 | The default is | |
478 | .Dq no . | |
479 | .It Cm GlobalKnownHostsFile | |
480 | Specifies a file to use for the global | |
481 | host key database instead of | |
482 | .Pa /etc/ssh/ssh_known_hosts . | |
70791e56 | 483 | .It Cm GSSAPIAuthentication |
416fd2a8 | 484 | Specifies whether user authentication based on GSSAPI is allowed. |
2e437378 | 485 | The default is |
ff2d7a98 | 486 | .Dq yes . |
70791e56 | 487 | Note that this option applies to protocol version 2 only. |
488 | .It Cm GSSAPIKeyExchange | |
98f19977 | 489 | Specifies whether key exchange based on GSSAPI may be used. When using |
490 | GSSAPI key exchange the server need not have a host key. | |
491 | The default is | |
492 | .Dq yes . | |
70791e56 | 493 | Note that this option applies to protocol version 2 only. |
494 | .It Cm GSSAPIDelegateCredentials | |
495 | Forward (delegate) credentials to the server. | |
ff2d7a98 | 496 | The default is |
497 | .Dq yes . | |
70791e56 | 498 | Note that this option applies to protocol version 2 only. |
34fee935 | 499 | .It Cm GSSAPITrustDns |
500 | Set to | |
2e437378 | 501 | .Dq yes |
502 | to indicate that the DNS is trusted to securely canonicalize | |
34fee935 | 503 | the name of the host being connected to. If |
2e437378 | 504 | .Dq no , |
505 | the hostname entered on the | |
34fee935 | 506 | command line will be passed untouched to the GSSAPI library. |
507 | The default is | |
508 | .Dq yes . | |
2e437378 | 509 | This option only applies to protocol version 2 connections using GSSAPI. |
34fee935 | 510 | .It Cm HashKnownHosts |
511 | Indicates that | |
2e437378 | 512 | .Xr ssh 1 |
34fee935 | 513 | should hash host names and addresses when they are added to |
514 | .Pa ~/.ssh/known_hosts . | |
515 | These hashed names may be used normally by | |
2e437378 | 516 | .Xr ssh 1 |
34fee935 | 517 | and |
2e437378 | 518 | .Xr sshd 8 , |
34fee935 | 519 | but they do not reveal identifying information should the file's contents |
520 | be disclosed. | |
521 | The default is | |
522 | .Dq no . | |
2e437378 | 523 | Note that existing names and addresses in known hosts files |
524 | will not be converted automatically, | |
525 | but may be manually hashed using | |
34fee935 | 526 | .Xr ssh-keygen 1 . |
ff2d7a98 | 527 | .It Cm HostbasedAuthentication |
528 | Specifies whether to try rhosts based authentication with public key | |
529 | authentication. | |
530 | The argument must be | |
531 | .Dq yes | |
532 | or | |
533 | .Dq no . | |
534 | The default is | |
535 | .Dq no . | |
536 | This option applies to protocol version 2 only and | |
537 | is similar to | |
538 | .Cm RhostsRSAAuthentication . | |
539 | .It Cm HostKeyAlgorithms | |
540 | Specifies the protocol version 2 host key algorithms | |
541 | that the client wants to use in order of preference. | |
542 | The default for this option is: | |
543 | .Dq ssh-rsa,ssh-dss . | |
544 | .It Cm HostKeyAlias | |
545 | Specifies an alias that should be used instead of the | |
546 | real host name when looking up or saving the host key | |
547 | in the host key database files. | |
2e437378 | 548 | This option is useful for tunneling SSH connections |
ff2d7a98 | 549 | or for multiple servers running on a single host. |
550 | .It Cm HostName | |
551 | Specifies the real host name to log into. | |
552 | This can be used to specify nicknames or abbreviations for hosts. | |
2e437378 | 553 | The default is the name given on the command line. |
ff2d7a98 | 554 | Numeric IP addresses are also permitted (both on the command line and in |
555 | .Cm HostName | |
556 | specifications). | |
2a304a95 | 557 | .It Cm IdentitiesOnly |
558 | Specifies that | |
2e437378 | 559 | .Xr ssh 1 |
2a304a95 | 560 | should only use the authentication identity files configured in the |
1b56ff3d | 561 | .Nm |
2a304a95 | 562 | files, |
2e437378 | 563 | even if |
564 | .Xr ssh-agent 1 | |
2a304a95 | 565 | offers more identities. |
566 | The argument to this keyword must be | |
567 | .Dq yes | |
568 | or | |
569 | .Dq no . | |
2e437378 | 570 | This option is intended for situations where ssh-agent |
2a304a95 | 571 | offers many different identities. |
572 | The default is | |
573 | .Dq no . | |
e00da40d | 574 | .It Cm IdentityFile |
575 | Specifies a file from which the user's RSA or DSA authentication identity | |
576 | is read. | |
577 | The default is | |
578 | .Pa ~/.ssh/identity | |
579 | for protocol version 1, and | |
580 | .Pa ~/.ssh/id_rsa | |
581 | and | |
582 | .Pa ~/.ssh/id_dsa | |
583 | for protocol version 2. | |
584 | Additionally, any identities represented by the authentication agent | |
585 | will be used for authentication. | |
2e437378 | 586 | .Pp |
e00da40d | 587 | The file name may use the tilde |
2e437378 | 588 | syntax to refer to a user's home directory or one of the following |
589 | escape characters: | |
590 | .Ql %d | |
591 | (local user's home directory), | |
592 | .Ql %u | |
593 | (local user name), | |
594 | .Ql %l | |
595 | (local host name), | |
596 | .Ql %h | |
597 | (remote host name) or | |
598 | .Ql %r | |
599 | (remote user name). | |
600 | .Pp | |
e00da40d | 601 | It is possible to have |
602 | multiple identity files specified in configuration files; all these | |
603 | identities will be tried in sequence. | |
34fee935 | 604 | .It Cm KbdInteractiveDevices |
605 | Specifies the list of methods to use in keyboard-interactive authentication. | |
606 | Multiple method names must be comma-separated. | |
607 | The default is to use the server specified list. | |
2e437378 | 608 | The methods available vary depending on what the server supports. |
609 | For an OpenSSH server, | |
610 | it may be zero or more of: | |
611 | .Dq bsdauth , | |
612 | .Dq pam , | |
613 | and | |
614 | .Dq skey . | |
e00da40d | 615 | .It Cm LocalCommand |
616 | Specifies a command to execute on the local machine after successfully | |
617 | connecting to the server. | |
618 | The command string extends to the end of the line, and is executed with | |
619 | .Pa /bin/sh . | |
620 | This directive is ignored unless | |
621 | .Cm PermitLocalCommand | |
622 | has been enabled. | |
ff2d7a98 | 623 | .It Cm LocalForward |
e00da40d | 624 | Specifies that a TCP port on the local machine be forwarded over |
ff2d7a98 | 625 | the secure channel to the specified host and port from the remote machine. |
34fee935 | 626 | The first argument must be |
627 | .Sm off | |
628 | .Oo Ar bind_address : Oc Ar port | |
629 | .Sm on | |
630 | and the second argument must be | |
631 | .Ar host : Ns Ar hostport . | |
632 | IPv6 addresses can be specified by enclosing addresses in square brackets or | |
633 | by using an alternative syntax: | |
634 | .Oo Ar bind_address Ns / Oc Ns Ar port | |
635 | and | |
636 | .Ar host Ns / Ns Ar hostport . | |
637 | Multiple forwardings may be specified, and additional forwardings can be | |
638 | given on the command line. | |
ff2d7a98 | 639 | Only the superuser can forward privileged ports. |
34fee935 | 640 | By default, the local port is bound in accordance with the |
641 | .Cm GatewayPorts | |
642 | setting. | |
643 | However, an explicit | |
644 | .Ar bind_address | |
645 | may be used to bind the connection to a specific address. | |
646 | The | |
647 | .Ar bind_address | |
648 | of | |
649 | .Dq localhost | |
650 | indicates that the listening port be bound for local use only, while an | |
651 | empty address or | |
652 | .Sq * | |
653 | indicates that the port should be available from all interfaces. | |
ff2d7a98 | 654 | .It Cm LogLevel |
655 | Gives the verbosity level that is used when logging messages from | |
2e437378 | 656 | .Xr ssh 1 . |
ff2d7a98 | 657 | The possible values are: |
2e437378 | 658 | QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. |
1c14df9e | 659 | The default is INFO. |
660 | DEBUG and DEBUG1 are equivalent. | |
661 | DEBUG2 and DEBUG3 each specify higher levels of verbose output. | |
ff2d7a98 | 662 | .It Cm MACs |
663 | Specifies the MAC (message authentication code) algorithms | |
664 | in order of preference. | |
665 | The MAC algorithm is used in protocol version 2 | |
666 | for data integrity protection. | |
667 | Multiple algorithms must be comma-separated. | |
2e437378 | 668 | The default is: |
ff2d7a98 | 669 | .Dq hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 . |
670 | .It Cm NoHostAuthenticationForLocalhost | |
671 | This option can be used if the home directory is shared across machines. | |
672 | In this case localhost will refer to a different machine on each of | |
673 | the machines and the user will get many warnings about changed host keys. | |
674 | However, this option disables host authentication for localhost. | |
675 | The argument to this keyword must be | |
676 | .Dq yes | |
677 | or | |
678 | .Dq no . | |
679 | The default is to check the host key for localhost. | |
680 | .It Cm NumberOfPasswordPrompts | |
681 | Specifies the number of password prompts before giving up. | |
682 | The argument to this keyword must be an integer. | |
2e437378 | 683 | The default is 3. |
ff2d7a98 | 684 | .It Cm PasswordAuthentication |
685 | Specifies whether to use password authentication. | |
686 | The argument to this keyword must be | |
687 | .Dq yes | |
688 | or | |
689 | .Dq no . | |
690 | The default is | |
691 | .Dq yes . | |
e00da40d | 692 | .It Cm PermitLocalCommand |
693 | Allow local command execution via the | |
694 | .Ic LocalCommand | |
695 | option or using the | |
696 | .Ic !\& Ns Ar command | |
697 | escape sequence in | |
698 | .Xr ssh 1 . | |
699 | The argument must be | |
700 | .Dq yes | |
701 | or | |
702 | .Dq no . | |
703 | The default is | |
704 | .Dq no . | |
ff2d7a98 | 705 | .It Cm Port |
706 | Specifies the port number to connect on the remote host. | |
2e437378 | 707 | The default is 22. |
ff2d7a98 | 708 | .It Cm PreferredAuthentications |
709 | Specifies the order in which the client should try protocol 2 | |
70791e56 | 710 | authentication methods. |
34fee935 | 711 | This allows a client to prefer one method (e.g.\& |
ff2d7a98 | 712 | .Cm keyboard-interactive ) |
34fee935 | 713 | over another method (e.g.\& |
ff2d7a98 | 714 | .Cm password ) |
715 | The default for this option is: | |
2e437378 | 716 | .Do gssapi-keyex , |
717 | external-keyx, | |
718 | gssapi-with-mic, | |
719 | hostbased, | |
720 | publickey, | |
721 | keyboard-interactive, | |
722 | password | |
723 | .Dc . | |
ff2d7a98 | 724 | .It Cm Protocol |
725 | Specifies the protocol versions | |
2e437378 | 726 | .Xr ssh 1 |
ff2d7a98 | 727 | should support in order of preference. |
728 | The possible values are | |
2e437378 | 729 | .Sq 1 |
ff2d7a98 | 730 | and |
2e437378 | 731 | .Sq 2 . |
ff2d7a98 | 732 | Multiple versions must be comma-separated. |
733 | The default is | |
734 | .Dq 2,1 . | |
2e437378 | 735 | This means that ssh |
ff2d7a98 | 736 | tries version 2 and falls back to version 1 |
737 | if version 2 is not available. | |
738 | .It Cm ProxyCommand | |
739 | Specifies the command to use to connect to the server. | |
740 | The command | |
741 | string extends to the end of the line, and is executed with | |
742 | .Pa /bin/sh . | |
743 | In the command string, | |
744 | .Ql %h | |
745 | will be substituted by the host name to | |
746 | connect and | |
747 | .Ql %p | |
748 | by the port. | |
749 | The command can be basically anything, | |
750 | and should read from its standard input and write to its standard output. | |
751 | It should eventually connect an | |
752 | .Xr sshd 8 | |
753 | server running on some machine, or execute | |
754 | .Ic sshd -i | |
755 | somewhere. | |
756 | Host key management will be done using the | |
757 | HostName of the host being connected (defaulting to the name typed by | |
758 | the user). | |
1c14df9e | 759 | Setting the command to |
760 | .Dq none | |
761 | disables this option entirely. | |
ff2d7a98 | 762 | Note that |
763 | .Cm CheckHostIP | |
764 | is not available for connects with a proxy command. | |
765 | .Pp | |
34fee935 | 766 | This directive is useful in conjunction with |
767 | .Xr nc 1 | |
768 | and its proxy support. | |
769 | For example, the following directive would connect via an HTTP proxy at | |
770 | 192.0.2.0: | |
771 | .Bd -literal -offset 3n | |
772 | ProxyCommand /usr/bin/nc -X connect -x 192.0.2.0:8080 %h %p | |
773 | .Ed | |
ff2d7a98 | 774 | .It Cm PubkeyAuthentication |
775 | Specifies whether to try public key authentication. | |
776 | The argument to this keyword must be | |
777 | .Dq yes | |
778 | or | |
779 | .Dq no . | |
780 | The default is | |
781 | .Dq yes . | |
782 | This option applies to protocol version 2 only. | |
e00da40d | 783 | .It Cm RekeyLimit |
784 | Specifies the maximum amount of data that may be transmitted before the | |
785 | session key is renegotiated. | |
786 | The argument is the number of bytes, with an optional suffix of | |
787 | .Sq K , | |
788 | .Sq M , | |
789 | or | |
790 | .Sq G | |
791 | to indicate Kilobytes, Megabytes, or Gigabytes, respectively. | |
792 | The default is between | |
2e437378 | 793 | .Sq 1G |
e00da40d | 794 | and |
2e437378 | 795 | .Sq 4G , |
e00da40d | 796 | depending on the cipher. |
797 | This option applies to protocol version 2 only. | |
ff2d7a98 | 798 | .It Cm RemoteForward |
e00da40d | 799 | Specifies that a TCP port on the remote machine be forwarded over |
ff2d7a98 | 800 | the secure channel to the specified host and port from the local machine. |
34fee935 | 801 | The first argument must be |
802 | .Sm off | |
803 | .Oo Ar bind_address : Oc Ar port | |
804 | .Sm on | |
805 | and the second argument must be | |
806 | .Ar host : Ns Ar hostport . | |
807 | IPv6 addresses can be specified by enclosing addresses in square brackets | |
808 | or by using an alternative syntax: | |
809 | .Oo Ar bind_address Ns / Oc Ns Ar port | |
810 | and | |
811 | .Ar host Ns / Ns Ar hostport . | |
ff2d7a98 | 812 | Multiple forwardings may be specified, and additional |
813 | forwardings can be given on the command line. | |
814 | Only the superuser can forward privileged ports. | |
34fee935 | 815 | .Pp |
816 | If the | |
817 | .Ar bind_address | |
818 | is not specified, the default is to only bind to loopback addresses. | |
819 | If the | |
820 | .Ar bind_address | |
821 | is | |
822 | .Ql * | |
823 | or an empty string, then the forwarding is requested to listen on all | |
824 | interfaces. | |
825 | Specifying a remote | |
826 | .Ar bind_address | |
827 | will only succeed if the server's | |
828 | .Cm GatewayPorts | |
829 | option is enabled (see | |
830 | .Xr sshd_config 5 ) . | |
ff2d7a98 | 831 | .It Cm RhostsRSAAuthentication |
832 | Specifies whether to try rhosts based authentication with RSA host | |
833 | authentication. | |
834 | The argument must be | |
835 | .Dq yes | |
836 | or | |
837 | .Dq no . | |
838 | The default is | |
839 | .Dq no . | |
840 | This option applies to protocol version 1 only and requires | |
2e437378 | 841 | .Xr ssh 1 |
ff2d7a98 | 842 | to be setuid root. |
843 | .It Cm RSAAuthentication | |
844 | Specifies whether to try RSA authentication. | |
845 | The argument to this keyword must be | |
846 | .Dq yes | |
847 | or | |
848 | .Dq no . | |
849 | RSA authentication will only be | |
850 | attempted if the identity file exists, or an authentication agent is | |
851 | running. | |
852 | The default is | |
853 | .Dq yes . | |
854 | Note that this option applies to protocol version 1 only. | |
1b56ff3d | 855 | .It Cm SendEnv |
856 | Specifies what variables from the local | |
857 | .Xr environ 7 | |
858 | should be sent to the server. | |
2e437378 | 859 | Note that environment passing is only supported for protocol 2. |
860 | The server must also support it, and the server must be configured to | |
1b56ff3d | 861 | accept these environment variables. |
862 | Refer to | |
863 | .Cm AcceptEnv | |
864 | in | |
865 | .Xr sshd_config 5 | |
866 | for how to configure the server. | |
2e437378 | 867 | Variables are specified by name, which may contain wildcard characters. |
1b56ff3d | 868 | Multiple environment variables may be separated by whitespace or spread |
869 | across multiple | |
870 | .Cm SendEnv | |
871 | directives. | |
872 | The default is not to send any environment variables. | |
2e437378 | 873 | .Pp |
874 | See | |
875 | .Sx PATTERNS | |
876 | for more information on patterns. | |
416fd2a8 | 877 | .It Cm ServerAliveCountMax |
e00da40d | 878 | Sets the number of server alive messages (see below) which may be |
416fd2a8 | 879 | sent without |
2e437378 | 880 | .Xr ssh 1 |
416fd2a8 | 881 | receiving any messages back from the server. |
882 | If this threshold is reached while server alive messages are being sent, | |
2e437378 | 883 | ssh will disconnect from the server, terminating the session. |
416fd2a8 | 884 | It is important to note that the use of server alive messages is very |
885 | different from | |
886 | .Cm TCPKeepAlive | |
887 | (below). | |
888 | The server alive messages are sent through the encrypted channel | |
889 | and therefore will not be spoofable. | |
890 | The TCP keepalive option enabled by | |
891 | .Cm TCPKeepAlive | |
892 | is spoofable. | |
893 | The server alive mechanism is valuable when the client or | |
894 | server depend on knowing when a connection has become inactive. | |
895 | .Pp | |
896 | The default value is 3. | |
897 | If, for example, | |
898 | .Cm ServerAliveInterval | |
2e437378 | 899 | (see below) is set to 15 and |
416fd2a8 | 900 | .Cm ServerAliveCountMax |
2e437378 | 901 | is left at the default, if the server becomes unresponsive, |
902 | ssh will disconnect after approximately 45 seconds. | |
903 | This option applies to protocol version 2 only. | |
e00da40d | 904 | .It Cm ServerAliveInterval |
905 | Sets a timeout interval in seconds after which if no data has been received | |
906 | from the server, | |
2e437378 | 907 | .Xr ssh 1 |
e00da40d | 908 | will send a message through the encrypted |
909 | channel to request a response from the server. | |
910 | The default | |
911 | is 0, indicating that these messages will not be sent to the server. | |
912 | This option applies to protocol version 2 only. | |
ff2d7a98 | 913 | .It Cm SmartcardDevice |
70791e56 | 914 | Specifies which smartcard device to use. |
915 | The argument to this keyword is the device | |
2e437378 | 916 | .Xr ssh 1 |
ff2d7a98 | 917 | should use to communicate with a smartcard used for storing the user's |
70791e56 | 918 | private RSA key. |
919 | By default, no device is specified and smartcard support is not activated. | |
ff2d7a98 | 920 | .It Cm StrictHostKeyChecking |
921 | If this flag is set to | |
922 | .Dq yes , | |
2e437378 | 923 | .Xr ssh 1 |
ff2d7a98 | 924 | will never automatically add host keys to the |
34fee935 | 925 | .Pa ~/.ssh/known_hosts |
ff2d7a98 | 926 | file, and refuses to connect to hosts whose host key has changed. |
927 | This provides maximum protection against trojan horse attacks, | |
2e437378 | 928 | though it can be annoying when the |
ff2d7a98 | 929 | .Pa /etc/ssh/ssh_known_hosts |
2e437378 | 930 | file is poorly maintained or when connections to new hosts are |
ff2d7a98 | 931 | frequently made. |
932 | This option forces the user to manually | |
933 | add all new hosts. | |
934 | If this flag is set to | |
935 | .Dq no , | |
2e437378 | 936 | ssh will automatically add new host keys to the |
ff2d7a98 | 937 | user known hosts files. |
938 | If this flag is set to | |
939 | .Dq ask , | |
940 | new host keys | |
941 | will be added to the user known host files only after the user | |
942 | has confirmed that is what they really want to do, and | |
2e437378 | 943 | ssh will refuse to connect to hosts whose host key has changed. |
ff2d7a98 | 944 | The host keys of |
945 | known hosts will be verified automatically in all cases. | |
946 | The argument must be | |
947 | .Dq yes , | |
2e437378 | 948 | .Dq no , |
ff2d7a98 | 949 | or |
950 | .Dq ask . | |
951 | The default is | |
952 | .Dq ask . | |
416fd2a8 | 953 | .It Cm TCPKeepAlive |
954 | Specifies whether the system should send TCP keepalive messages to the | |
955 | other side. | |
956 | If they are sent, death of the connection or crash of one | |
957 | of the machines will be properly noticed. | |
958 | However, this means that | |
959 | connections will die if the route is down temporarily, and some people | |
960 | find it annoying. | |
961 | .Pp | |
962 | The default is | |
963 | .Dq yes | |
964 | (to send TCP keepalive messages), and the client will notice | |
965 | if the network goes down or the remote host dies. | |
966 | This is important in scripts, and many users want it too. | |
967 | .Pp | |
968 | To disable TCP keepalive messages, the value should be set to | |
969 | .Dq no . | |
e00da40d | 970 | .It Cm Tunnel |
2e437378 | 971 | Request |
e00da40d | 972 | .Xr tun 4 |
973 | device forwarding between the client and the server. | |
e00da40d | 974 | The argument must be |
975 | .Dq yes , | |
2e437378 | 976 | .Dq point-to-point |
977 | (layer 3), | |
e00da40d | 978 | .Dq ethernet |
2e437378 | 979 | (layer 2), |
e00da40d | 980 | or |
981 | .Dq no . | |
2e437378 | 982 | Specifying |
983 | .Dq yes | |
984 | requests the default tunnel mode, which is | |
985 | .Dq point-to-point . | |
e00da40d | 986 | The default is |
987 | .Dq no . | |
988 | .It Cm TunnelDevice | |
2e437378 | 989 | Specifies the |
e00da40d | 990 | .Xr tun 4 |
2e437378 | 991 | devices to open on the client |
992 | .Pq Ar local_tun | |
993 | and the server | |
994 | .Pq Ar remote_tun . | |
995 | .Pp | |
996 | The argument must be | |
997 | .Sm off | |
998 | .Ar local_tun Op : Ar remote_tun . | |
999 | .Sm on | |
1000 | The devices may be specified by numerical ID or the keyword | |
1001 | .Dq any , | |
1002 | which uses the next available tunnel device. | |
1003 | If | |
1004 | .Ar remote_tun | |
1005 | is not specified, it defaults to | |
1006 | .Dq any . | |
1007 | The default is | |
1008 | .Dq any:any . | |
ff2d7a98 | 1009 | .It Cm UsePrivilegedPort |
1010 | Specifies whether to use a privileged port for outgoing connections. | |
1011 | The argument must be | |
1012 | .Dq yes | |
1013 | or | |
1014 | .Dq no . | |
1015 | The default is | |
1016 | .Dq no . | |
e54b3d7c | 1017 | If set to |
2e437378 | 1018 | .Dq yes , |
1019 | .Xr ssh 1 | |
e54b3d7c | 1020 | must be setuid root. |
ff2d7a98 | 1021 | Note that this option must be set to |
1022 | .Dq yes | |
70791e56 | 1023 | for |
ff2d7a98 | 1024 | .Cm RhostsRSAAuthentication |
70791e56 | 1025 | with older servers. |
ff2d7a98 | 1026 | .It Cm User |
1027 | Specifies the user to log in as. | |
1028 | This can be useful when a different user name is used on different machines. | |
1029 | This saves the trouble of | |
1030 | having to remember to give the user name on the command line. | |
1031 | .It Cm UserKnownHostsFile | |
1032 | Specifies a file to use for the user | |
1033 | host key database instead of | |
34fee935 | 1034 | .Pa ~/.ssh/known_hosts . |
70791e56 | 1035 | .It Cm VerifyHostKeyDNS |
1036 | Specifies whether to verify the remote key using DNS and SSHFP resource | |
1037 | records. | |
416fd2a8 | 1038 | If this option is set to |
1039 | .Dq yes , | |
1040 | the client will implicitly trust keys that match a secure fingerprint | |
1041 | from DNS. | |
1042 | Insecure fingerprints will be handled as if this option was set to | |
1043 | .Dq ask . | |
1044 | If this option is set to | |
1045 | .Dq ask , | |
1046 | information on fingerprint match will be displayed, but the user will still | |
1047 | need to confirm new host keys according to the | |
1048 | .Cm StrictHostKeyChecking | |
1049 | option. | |
1050 | The argument must be | |
1051 | .Dq yes , | |
2e437378 | 1052 | .Dq no , |
416fd2a8 | 1053 | or |
1054 | .Dq ask . | |
70791e56 | 1055 | The default is |
1056 | .Dq no . | |
1057 | Note that this option applies to protocol version 2 only. | |
2e437378 | 1058 | .Pp |
1059 | See also | |
1060 | .Sx VERIFYING HOST KEYS | |
1061 | in | |
1062 | .Xr ssh 1 . | |
ff2d7a98 | 1063 | .It Cm XAuthLocation |
e54b3d7c | 1064 | Specifies the full pathname of the |
ff2d7a98 | 1065 | .Xr xauth 1 |
1066 | program. | |
1067 | The default is | |
1068 | .Pa /usr/X11R6/bin/xauth . | |
1069 | .El | |
2e437378 | 1070 | .Sh PATTERNS |
1071 | A | |
1072 | .Em pattern | |
1073 | consists of zero or more non-whitespace characters, | |
1074 | .Sq * | |
1075 | (a wildcard that matches zero or more characters), | |
1076 | or | |
1077 | .Sq ?\& | |
1078 | (a wildcard that matches exactly one character). | |
1079 | For example, to specify a set of declarations for any host in the | |
1080 | .Dq .co.uk | |
1081 | set of domains, | |
1082 | the following pattern could be used: | |
1083 | .Pp | |
1084 | .Dl Host *.co.uk | |
1085 | .Pp | |
1086 | The following pattern | |
1087 | would match any host in the 192.168.0.[0-9] network range: | |
1088 | .Pp | |
1089 | .Dl Host 192.168.0.? | |
1090 | .Pp | |
1091 | A | |
1092 | .Em pattern-list | |
1093 | is a comma-separated list of patterns. | |
1094 | Patterns within pattern-lists may be negated | |
1095 | by preceding them with an exclamation mark | |
1096 | .Pq Sq !\& . | |
1097 | For example, | |
1098 | to allow a key to be used from anywhere within an organisation | |
1099 | except from the | |
1100 | .Dq dialup | |
1101 | pool, | |
1102 | the following entry (in authorized_keys) could be used: | |
1103 | .Pp | |
1104 | .Dl from=\&"!*.dialup.example.com,*.example.com\&" | |
ff2d7a98 | 1105 | .Sh FILES |
1106 | .Bl -tag -width Ds | |
34fee935 | 1107 | .It Pa ~/.ssh/config |
ff2d7a98 | 1108 | This is the per-user configuration file. |
1109 | The format of this file is described above. | |
2e437378 | 1110 | This file is used by the SSH client. |
1b56ff3d | 1111 | Because of the potential for abuse, this file must have strict permissions: |
1112 | read/write for the user, and not accessible by others. | |
ff2d7a98 | 1113 | .It Pa /etc/ssh/ssh_config |
1114 | Systemwide configuration file. | |
1115 | This file provides defaults for those | |
1116 | values that are not specified in the user's configuration file, and | |
1117 | for those users who do not have a configuration file. | |
1118 | This file must be world-readable. | |
1119 | .El | |
70791e56 | 1120 | .Sh SEE ALSO |
1121 | .Xr ssh 1 | |
ff2d7a98 | 1122 | .Sh AUTHORS |
1123 | OpenSSH is a derivative of the original and free | |
1124 | ssh 1.2.12 release by Tatu Ylonen. | |
1125 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, | |
1126 | Theo de Raadt and Dug Song | |
1127 | removed many bugs, re-added newer features and | |
1128 | created OpenSSH. | |
1129 | Markus Friedl contributed the support for SSH | |
1130 | protocol versions 1.5 and 2.0. |