]>
Commit | Line | Data |
---|---|---|
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 | .\" | |
5262cbfb | 37 | .\" $OpenBSD: sshd_config.5,v 1.102 2009/02/22 23:59:25 djm Exp $ |
38 | .Dd $Mdocdate: February 22 2009 $ | |
884dc78b | 39 | .Dt SSHD_CONFIG 5 |
40 | .Os | |
41 | .Sh NAME | |
42 | .Nm sshd_config | |
43 | .Nd OpenSSH SSH daemon configuration file | |
44 | .Sh SYNOPSIS | |
0b90ac93 | 45 | .Nm /etc/ssh/sshd_config |
884dc78b | 46 | .Sh DESCRIPTION |
30460aeb | 47 | .Xr sshd 8 |
884dc78b | 48 | reads configuration data from |
49 | .Pa /etc/ssh/sshd_config | |
50 | (or the file specified with | |
51 | .Fl f | |
52 | on the command line). | |
53 | The file contains keyword-argument pairs, one per line. | |
54 | Lines starting with | |
55 | .Ql # | |
56 | and empty lines are interpreted as comments. | |
30460aeb | 57 | Arguments may optionally be enclosed in double quotes |
58 | .Pq \&" | |
59 | in order to represent arguments containing spaces. | |
884dc78b | 60 | .Pp |
61 | The possible | |
62 | keywords and their meanings are as follows (note that | |
63 | keywords are case-insensitive and arguments are case-sensitive): | |
64 | .Bl -tag -width Ds | |
7e82606e | 65 | .It Cm AcceptEnv |
66 | Specifies what environment variables sent by the client will be copied into | |
67 | the session's | |
68 | .Xr environ 7 . | |
69 | See | |
70 | .Cm SendEnv | |
71 | in | |
72 | .Xr ssh_config 5 | |
73 | for how to configure the client. | |
74 | Note that environment passing is only supported for protocol 2. | |
75 | Variables are specified by name, which may contain the wildcard characters | |
30460aeb | 76 | .Ql * |
7e82606e | 77 | and |
78 | .Ql \&? . | |
79 | Multiple environment variables may be separated by whitespace or spread | |
80 | across multiple | |
81 | .Cm AcceptEnv | |
82 | directives. | |
83 | Be warned that some environment variables could be used to bypass restricted | |
84 | user environments. | |
85 | For this reason, care should be taken in the use of this directive. | |
86 | The default is not to accept any environment variables. | |
dfddba3d | 87 | .It Cm AddressFamily |
88 | Specifies which address family should be used by | |
30460aeb | 89 | .Xr sshd 8 . |
dfddba3d | 90 | Valid arguments are |
91 | .Dq any , | |
92 | .Dq inet | |
30460aeb | 93 | (use IPv4 only), or |
dfddba3d | 94 | .Dq inet6 |
95 | (use IPv6 only). | |
96 | The default is | |
97 | .Dq any . | |
5156b1a1 | 98 | .It Cm AllowAgentForwarding |
99 | Specifies whether | |
100 | .Xr ssh-agent 1 | |
101 | forwarding is permitted. | |
102 | The default is | |
103 | .Dq yes . | |
104 | Note that disabling agent forwarding does not improve security | |
105 | unless users are also denied shell access, as they can always install | |
106 | their own forwarders. | |
884dc78b | 107 | .It Cm AllowGroups |
108 | This keyword can be followed by a list of group name patterns, separated | |
109 | by spaces. | |
110 | If specified, login is allowed only for users whose primary | |
111 | group or supplementary group list matches one of the patterns. | |
884dc78b | 112 | Only group names are valid; a numerical group ID is not recognized. |
113 | By default, login is allowed for all groups. | |
30460aeb | 114 | The allow/deny directives are processed in the following order: |
115 | .Cm DenyUsers , | |
116 | .Cm AllowUsers , | |
117 | .Cm DenyGroups , | |
118 | and finally | |
119 | .Cm AllowGroups . | |
120 | .Pp | |
121 | See | |
122 | .Sx PATTERNS | |
123 | in | |
124 | .Xr ssh_config 5 | |
125 | for more information on patterns. | |
884dc78b | 126 | .It Cm AllowTcpForwarding |
127 | Specifies whether TCP forwarding is permitted. | |
128 | The default is | |
129 | .Dq yes . | |
130 | Note that disabling TCP forwarding does not improve security unless | |
131 | users are also denied shell access, as they can always install their | |
132 | own forwarders. | |
884dc78b | 133 | .It Cm AllowUsers |
134 | This keyword can be followed by a list of user name patterns, separated | |
135 | by spaces. | |
bfe49944 | 136 | If specified, login is allowed only for user names that |
884dc78b | 137 | match one of the patterns. |
884dc78b | 138 | Only user names are valid; a numerical user ID is not recognized. |
139 | By default, login is allowed for all users. | |
140 | If the pattern takes the form USER@HOST then USER and HOST | |
141 | are separately checked, restricting logins to particular | |
142 | users from particular hosts. | |
30460aeb | 143 | The allow/deny directives are processed in the following order: |
144 | .Cm DenyUsers , | |
145 | .Cm AllowUsers , | |
146 | .Cm DenyGroups , | |
147 | and finally | |
148 | .Cm AllowGroups . | |
149 | .Pp | |
150 | See | |
151 | .Sx PATTERNS | |
152 | in | |
153 | .Xr ssh_config 5 | |
154 | for more information on patterns. | |
884dc78b | 155 | .It Cm AuthorizedKeysFile |
156 | Specifies the file that contains the public keys that can be used | |
157 | for user authentication. | |
158 | .Cm AuthorizedKeysFile | |
159 | may contain tokens of the form %T which are substituted during connection | |
30460aeb | 160 | setup. |
7cac2b65 | 161 | The following tokens are defined: %% is replaced by a literal '%', |
30460aeb | 162 | %h is replaced by the home directory of the user being authenticated, and |
884dc78b | 163 | %u is replaced by the username of that user. |
164 | After expansion, | |
165 | .Cm AuthorizedKeysFile | |
166 | is taken to be an absolute path or one relative to the user's home | |
167 | directory. | |
168 | The default is | |
169 | .Dq .ssh/authorized_keys . | |
170 | .It Cm Banner | |
884dc78b | 171 | The contents of the specified file are sent to the remote user before |
172 | authentication is allowed. | |
e74dc197 | 173 | If the argument is |
174 | .Dq none | |
175 | then no banner is displayed. | |
884dc78b | 176 | This option is only available for protocol version 2. |
177 | By default, no banner is displayed. | |
884dc78b | 178 | .It Cm ChallengeResponseAuthentication |
30460aeb | 179 | Specifies whether challenge-response authentication is allowed. |
884dc78b | 180 | All authentication styles from |
181 | .Xr login.conf 5 | |
182 | are supported. | |
183 | The default is | |
184 | .Dq yes . | |
e74dc197 | 185 | .It Cm ChrootDirectory |
186 | Specifies a path to | |
187 | .Xr chroot 2 | |
188 | to after authentication. | |
189 | This path, and all its components, must be root-owned directories that are | |
190 | not writable by any other user or group. | |
191 | .Pp | |
192 | The path may contain the following tokens that are expanded at runtime once | |
193 | the connecting user has been authenticated: %% is replaced by a literal '%', | |
194 | %h is replaced by the home directory of the user being authenticated, and | |
195 | %u is replaced by the username of that user. | |
196 | .Pp | |
197 | The | |
198 | .Cm ChrootDirectory | |
199 | must contain the necessary files and directories to support the | |
200 | users' session. | |
201 | For an interactive session this requires at least a shell, typically | |
202 | .Xr sh 1 , | |
203 | and basic | |
204 | .Pa /dev | |
205 | nodes such as | |
206 | .Xr null 4 , | |
207 | .Xr zero 4 , | |
208 | .Xr stdin 4 , | |
209 | .Xr stdout 4 , | |
210 | .Xr stderr 4 , | |
211 | .Xr arandom 4 | |
212 | and | |
213 | .Xr tty 4 | |
214 | devices. | |
215 | For file transfer sessions using | |
216 | .Dq sftp , | |
217 | no additional configuration of the environment is necessary if the | |
218 | in-process sftp server is used (see | |
219 | .Cm Subsystem | |
220 | for details). | |
221 | .Pp | |
222 | The default is not to | |
223 | .Xr chroot 2 . | |
884dc78b | 224 | .It Cm Ciphers |
225 | Specifies the ciphers allowed for protocol version 2. | |
226 | Multiple ciphers must be comma-separated. | |
7e82606e | 227 | The supported ciphers are |
228 | .Dq 3des-cbc , | |
229 | .Dq aes128-cbc , | |
230 | .Dq aes192-cbc , | |
231 | .Dq aes256-cbc , | |
232 | .Dq aes128-ctr , | |
233 | .Dq aes192-ctr , | |
234 | .Dq aes256-ctr , | |
2ce0bfe4 | 235 | .Dq arcfour128 , |
236 | .Dq arcfour256 , | |
7e82606e | 237 | .Dq arcfour , |
238 | .Dq blowfish-cbc , | |
239 | and | |
240 | .Dq cast128-cbc . | |
30460aeb | 241 | The default is: |
242 | .Bd -literal -offset 3n | |
5262cbfb | 243 | aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128, |
244 | aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc, | |
245 | aes256-cbc,arcfour | |
884dc78b | 246 | .Ed |
884dc78b | 247 | .It Cm ClientAliveCountMax |
08822d99 | 248 | Sets the number of client alive messages (see below) which may be |
884dc78b | 249 | sent without |
30460aeb | 250 | .Xr sshd 8 |
7cac2b65 | 251 | receiving any messages back from the client. |
252 | If this threshold is reached while client alive messages are being sent, | |
30460aeb | 253 | sshd will disconnect the client, terminating the session. |
7cac2b65 | 254 | It is important to note that the use of client alive messages is very |
255 | different from | |
540d72c3 | 256 | .Cm TCPKeepAlive |
7cac2b65 | 257 | (below). |
258 | The client alive messages are sent through the encrypted channel | |
259 | and therefore will not be spoofable. | |
260 | The TCP keepalive option enabled by | |
540d72c3 | 261 | .Cm TCPKeepAlive |
7cac2b65 | 262 | is spoofable. |
263 | The client alive mechanism is valuable when the client or | |
884dc78b | 264 | server depend on knowing when a connection has become inactive. |
265 | .Pp | |
7cac2b65 | 266 | The default value is 3. |
267 | If | |
884dc78b | 268 | .Cm ClientAliveInterval |
08822d99 | 269 | (see below) is set to 15, and |
884dc78b | 270 | .Cm ClientAliveCountMax |
30460aeb | 271 | is left at the default, unresponsive SSH clients |
884dc78b | 272 | will be disconnected after approximately 45 seconds. |
30460aeb | 273 | This option applies to protocol version 2 only. |
2ce0bfe4 | 274 | .It Cm ClientAliveInterval |
275 | Sets a timeout interval in seconds after which if no data has been received | |
276 | from the client, | |
30460aeb | 277 | .Xr sshd 8 |
2ce0bfe4 | 278 | will send a message through the encrypted |
279 | channel to request a response from the client. | |
280 | The default | |
281 | is 0, indicating that these messages will not be sent to the client. | |
282 | This option applies to protocol version 2 only. | |
884dc78b | 283 | .It Cm Compression |
2ce0bfe4 | 284 | Specifies whether compression is allowed, or delayed until |
285 | the user has authenticated successfully. | |
884dc78b | 286 | The argument must be |
2ce0bfe4 | 287 | .Dq yes , |
288 | .Dq delayed , | |
884dc78b | 289 | or |
290 | .Dq no . | |
291 | The default is | |
2ce0bfe4 | 292 | .Dq delayed . |
884dc78b | 293 | .It Cm DenyGroups |
294 | This keyword can be followed by a list of group name patterns, separated | |
295 | by spaces. | |
296 | Login is disallowed for users whose primary group or supplementary | |
297 | group list matches one of the patterns. | |
884dc78b | 298 | Only group names are valid; a numerical group ID is not recognized. |
299 | By default, login is allowed for all groups. | |
30460aeb | 300 | The allow/deny directives are processed in the following order: |
301 | .Cm DenyUsers , | |
302 | .Cm AllowUsers , | |
303 | .Cm DenyGroups , | |
304 | and finally | |
305 | .Cm AllowGroups . | |
306 | .Pp | |
307 | See | |
308 | .Sx PATTERNS | |
309 | in | |
310 | .Xr ssh_config 5 | |
311 | for more information on patterns. | |
884dc78b | 312 | .It Cm DenyUsers |
313 | This keyword can be followed by a list of user name patterns, separated | |
314 | by spaces. | |
315 | Login is disallowed for user names that match one of the patterns. | |
884dc78b | 316 | Only user names are valid; a numerical user ID is not recognized. |
317 | By default, login is allowed for all users. | |
318 | If the pattern takes the form USER@HOST then USER and HOST | |
319 | are separately checked, restricting logins to particular | |
320 | users from particular hosts. | |
30460aeb | 321 | The allow/deny directives are processed in the following order: |
322 | .Cm DenyUsers , | |
323 | .Cm AllowUsers , | |
324 | .Cm DenyGroups , | |
325 | and finally | |
326 | .Cm AllowGroups . | |
327 | .Pp | |
328 | See | |
329 | .Sx PATTERNS | |
330 | in | |
331 | .Xr ssh_config 5 | |
332 | for more information on patterns. | |
333 | .It Cm ForceCommand | |
334 | Forces the execution of the command specified by | |
335 | .Cm ForceCommand , | |
e74dc197 | 336 | ignoring any command supplied by the client and |
337 | .Pa ~/.ssh/rc | |
338 | if present. | |
30460aeb | 339 | The command is invoked by using the user's login shell with the -c option. |
340 | This applies to shell, command, or subsystem execution. | |
341 | It is most useful inside a | |
342 | .Cm Match | |
343 | block. | |
344 | The command originally supplied by the client is available in the | |
345 | .Ev SSH_ORIGINAL_COMMAND | |
346 | environment variable. | |
e74dc197 | 347 | Specifying a command of |
348 | .Dq internal-sftp | |
349 | will force the use of an in-process sftp server that requires no support | |
350 | files when used with | |
351 | .Cm ChrootDirectory . | |
884dc78b | 352 | .It Cm GatewayPorts |
353 | Specifies whether remote hosts are allowed to connect to ports | |
354 | forwarded for the client. | |
355 | By default, | |
30460aeb | 356 | .Xr sshd 8 |
bfe49944 | 357 | binds remote port forwardings to the loopback address. |
358 | This prevents other remote hosts from connecting to forwarded ports. | |
884dc78b | 359 | .Cm GatewayPorts |
30460aeb | 360 | can be used to specify that sshd |
dfddba3d | 361 | should allow remote port forwardings to bind to non-loopback addresses, thus |
362 | allowing other hosts to connect. | |
363 | The argument may be | |
364 | .Dq no | |
365 | to force remote port forwardings to be available to the local host only, | |
884dc78b | 366 | .Dq yes |
dfddba3d | 367 | to force remote port forwardings to bind to the wildcard address, or |
368 | .Dq clientspecified | |
369 | to allow the client to select the address to which the forwarding is bound. | |
884dc78b | 370 | The default is |
371 | .Dq no . | |
7cac2b65 | 372 | .It Cm GSSAPIAuthentication |
373 | Specifies whether user authentication based on GSSAPI is allowed. | |
540d72c3 | 374 | The default is |
c5448518 | 375 | .Dq yes . |
7cac2b65 | 376 | Note that this option applies to protocol version 2 only. |
05ed7e1e | 377 | .It Cm GSSAPIDelegateCredentials |
378 | Specifies whether delegated credentials are stored in the user's environment. | |
379 | The default is | |
380 | .Dq yes . | |
c5448518 | 381 | .It Cm GSSAPIKeyExchange |
fe4ad273 | 382 | Specifies whether key exchange based on GSSAPI is allowed. GSSAPI key exchange |
383 | doesn't rely on ssh keys to verify host identity. | |
44a053a3 | 384 | The default is |
385 | .Dq yes . | |
c5448518 | 386 | Note that this option applies to protocol version 2 only. |
fe4ad273 | 387 | .It Cm GSSAPICleanupCredentials |
388 | Specifies whether to automatically destroy the user's credentials cache | |
389 | on logout. | |
44a053a3 | 390 | The default is |
391 | .Dq yes . | |
c5448518 | 392 | Note that this option applies to protocol version 2 only. |
f713db99 | 393 | .It Cm GSSAPIStrictAcceptorCheck |
394 | Determines whether to be strict about the identity of the GSSAPI acceptor | |
395 | a client authenticates against. If | |
396 | .Dq yes | |
397 | then the client must authenticate against the | |
398 | .Pa host | |
399 | service on the current hostname. If | |
400 | .Dq no | |
401 | then the client may authenticate against any service key stored in the | |
402 | machine's default store. This facility is provided to assist with operation | |
403 | on multi homed machines. | |
404 | The default is | |
405 | .Dq yes . | |
406 | Note that this option applies only to protocol version 2 GSSAPI connections, | |
407 | and setting it to | |
408 | .Dq no | |
409 | may only work with recent Kerberos GSSAPI libraries. | |
ae82558b | 410 | .It Cm GSSAPICredentialsPath |
411 | If specified, the delegated GSSAPI credential is stored in the | |
412 | given path, overwriting any existing credentials. | |
413 | Paths can be specified with syntax similar to the AuthorizedKeysFile | |
414 | option (i.e., accepting %h and %u tokens). | |
415 | When using this option, | |
416 | setting 'GssapiCleanupCredentials no' is recommended, | |
417 | so logging out of one session | |
418 | doesn't remove the credentials in use by another session of | |
419 | the same user. | |
420 | Currently only implemented for the GSI mechanism. | |
826a9049 | 421 | .It Cm GSIAllowLimitedProxy |
422 | Specifies whether to accept limited proxy credentials for | |
423 | authentication. | |
424 | The default is | |
425 | .Dq no . | |
c5448518 | 426 | .It Cm HostbasedAuthentication |
427 | Specifies whether rhosts or /etc/hosts.equiv authentication together | |
428 | with successful public key client host authentication is allowed | |
30460aeb | 429 | (host-based authentication). |
c5448518 | 430 | This option is similar to |
431 | .Cm RhostsRSAAuthentication | |
432 | and applies to protocol version 2 only. | |
52b36949 | 433 | The default is |
c5448518 | 434 | .Dq no . |
30460aeb | 435 | .It Cm HostbasedUsesNameFromPacketOnly |
436 | Specifies whether or not the server will attempt to perform a reverse | |
437 | name lookup when matching the name in the | |
438 | .Pa ~/.shosts , | |
439 | .Pa ~/.rhosts , | |
440 | and | |
441 | .Pa /etc/hosts.equiv | |
442 | files during | |
443 | .Cm HostbasedAuthentication . | |
444 | A setting of | |
445 | .Dq yes | |
446 | means that | |
447 | .Xr sshd 8 | |
448 | uses the name supplied by the client rather than | |
449 | attempting to resolve the name from the TCP connection itself. | |
450 | The default is | |
451 | .Dq no . | |
884dc78b | 452 | .It Cm HostKey |
453 | Specifies a file containing a private host key | |
454 | used by SSH. | |
455 | The default is | |
456 | .Pa /etc/ssh/ssh_host_key | |
457 | for protocol version 1, and | |
458 | .Pa /etc/ssh/ssh_host_rsa_key | |
459 | and | |
460 | .Pa /etc/ssh/ssh_host_dsa_key | |
461 | for protocol version 2. | |
462 | Note that | |
30460aeb | 463 | .Xr sshd 8 |
884dc78b | 464 | will refuse to use a file if it is group/world-accessible. |
465 | It is possible to have multiple host key files. | |
466 | .Dq rsa1 | |
467 | keys are used for version 1 and | |
468 | .Dq dsa | |
469 | or | |
470 | .Dq rsa | |
471 | are used for version 2 of the SSH protocol. | |
472 | .It Cm IgnoreRhosts | |
473 | Specifies that | |
474 | .Pa .rhosts | |
475 | and | |
476 | .Pa .shosts | |
477 | files will not be used in | |
884dc78b | 478 | .Cm RhostsRSAAuthentication |
479 | or | |
480 | .Cm HostbasedAuthentication . | |
481 | .Pp | |
482 | .Pa /etc/hosts.equiv | |
483 | and | |
484 | .Pa /etc/shosts.equiv | |
485 | are still used. | |
486 | The default is | |
487 | .Dq yes . | |
488 | .It Cm IgnoreUserKnownHosts | |
489 | Specifies whether | |
30460aeb | 490 | .Xr sshd 8 |
884dc78b | 491 | should ignore the user's |
2ce0bfe4 | 492 | .Pa ~/.ssh/known_hosts |
884dc78b | 493 | during |
494 | .Cm RhostsRSAAuthentication | |
495 | or | |
496 | .Cm HostbasedAuthentication . | |
497 | The default is | |
498 | .Dq no . | |
884dc78b | 499 | .It Cm KerberosAuthentication |
7cac2b65 | 500 | Specifies whether the password provided by the user for |
884dc78b | 501 | .Cm PasswordAuthentication |
7cac2b65 | 502 | will be validated through the Kerberos KDC. |
884dc78b | 503 | To use this option, the server needs a |
504 | Kerberos servtab which allows the verification of the KDC's identity. | |
30460aeb | 505 | The default is |
884dc78b | 506 | .Dq no . |
12a403af | 507 | .It Cm KerberosGetAFSToken |
08822d99 | 508 | If AFS is active and the user has a Kerberos 5 TGT, attempt to acquire |
12a403af | 509 | an AFS token before accessing the user's home directory. |
30460aeb | 510 | The default is |
12a403af | 511 | .Dq no . |
884dc78b | 512 | .It Cm KerberosOrLocalPasswd |
30460aeb | 513 | If password authentication through Kerberos fails then |
884dc78b | 514 | the password will be validated via any additional local mechanism |
515 | such as | |
516 | .Pa /etc/passwd . | |
30460aeb | 517 | The default is |
884dc78b | 518 | .Dq yes . |
884dc78b | 519 | .It Cm KerberosTicketCleanup |
520 | Specifies whether to automatically destroy the user's ticket cache | |
521 | file on logout. | |
30460aeb | 522 | The default is |
884dc78b | 523 | .Dq yes . |
524 | .It Cm KeyRegenerationInterval | |
525 | In protocol version 1, the ephemeral server key is automatically regenerated | |
526 | after this many seconds (if it has been used). | |
527 | The purpose of regeneration is to prevent | |
528 | decrypting captured sessions by later breaking into the machine and | |
529 | stealing the keys. | |
530 | The key is never stored anywhere. | |
531 | If the value is 0, the key is never regenerated. | |
532 | The default is 3600 (seconds). | |
533 | .It Cm ListenAddress | |
534 | Specifies the local addresses | |
30460aeb | 535 | .Xr sshd 8 |
884dc78b | 536 | should listen on. |
537 | The following forms may be used: | |
538 | .Pp | |
539 | .Bl -item -offset indent -compact | |
540 | .It | |
541 | .Cm ListenAddress | |
542 | .Sm off | |
543 | .Ar host No | Ar IPv4_addr No | Ar IPv6_addr | |
544 | .Sm on | |
545 | .It | |
546 | .Cm ListenAddress | |
547 | .Sm off | |
548 | .Ar host No | Ar IPv4_addr No : Ar port | |
549 | .Sm on | |
550 | .It | |
551 | .Cm ListenAddress | |
552 | .Sm off | |
553 | .Oo | |
554 | .Ar host No | Ar IPv6_addr Oc : Ar port | |
555 | .Sm on | |
556 | .El | |
557 | .Pp | |
558 | If | |
559 | .Ar port | |
560 | is not specified, | |
30460aeb | 561 | sshd will listen on the address and all prior |
884dc78b | 562 | .Cm Port |
7cac2b65 | 563 | options specified. |
564 | The default is to listen on all local addresses. | |
bfe49944 | 565 | Multiple |
884dc78b | 566 | .Cm ListenAddress |
7cac2b65 | 567 | options are permitted. |
568 | Additionally, any | |
884dc78b | 569 | .Cm Port |
30460aeb | 570 | options must precede this option for non-port qualified addresses. |
884dc78b | 571 | .It Cm LoginGraceTime |
572 | The server disconnects after this time if the user has not | |
573 | successfully logged in. | |
574 | If the value is 0, there is no time limit. | |
d03f4262 | 575 | The default is 120 seconds. |
884dc78b | 576 | .It Cm LogLevel |
577 | Gives the verbosity level that is used when logging messages from | |
30460aeb | 578 | .Xr sshd 8 . |
884dc78b | 579 | The possible values are: |
30460aeb | 580 | QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3. |
bfe49944 | 581 | The default is INFO. |
582 | DEBUG and DEBUG1 are equivalent. | |
583 | DEBUG2 and DEBUG3 each specify higher levels of debugging output. | |
584 | Logging with a DEBUG level violates the privacy of users and is not recommended. | |
884dc78b | 585 | .It Cm MACs |
586 | Specifies the available MAC (message authentication code) algorithms. | |
587 | The MAC algorithm is used in protocol version 2 | |
588 | for data integrity protection. | |
589 | Multiple algorithms must be comma-separated. | |
30460aeb | 590 | The default is: |
fa0f0f45 | 591 | .Bd -literal -offset indent |
592 | hmac-md5,hmac-sha1,umac-64@openssh.com, | |
593 | hmac-ripemd160,hmac-sha1-96,hmac-md5-96 | |
594 | .Ed | |
30460aeb | 595 | .It Cm Match |
596 | Introduces a conditional block. | |
597 | If all of the criteria on the | |
598 | .Cm Match | |
599 | line are satisfied, the keywords on the following lines override those | |
600 | set in the global section of the config file, until either another | |
601 | .Cm Match | |
602 | line or the end of the file. | |
5156b1a1 | 603 | .Pp |
30460aeb | 604 | The arguments to |
605 | .Cm Match | |
606 | are one or more criteria-pattern pairs. | |
607 | The available criteria are | |
608 | .Cm User , | |
609 | .Cm Group , | |
610 | .Cm Host , | |
611 | and | |
612 | .Cm Address . | |
5156b1a1 | 613 | The match patterns may consist of single entries or comma-separated |
614 | lists and may use the wildcard and negation operators described in the | |
615 | .Sx PATTERNS | |
616 | section of | |
617 | .Xr ssh_config 5 . | |
618 | .Pp | |
619 | The patterns in an | |
620 | .Cm Address | |
621 | criteria may additionally contain addresses to match in CIDR | |
622 | address/masklen format, e.g.\& | |
623 | .Dq 192.0.2.0/24 | |
624 | or | |
625 | .Dq 3ffe:ffff::/32 . | |
626 | Note that the mask length provided must be consistent with the address - | |
627 | it is an error to specify a mask length that is too long for the address | |
628 | or one with bits set in this host portion of the address. | |
629 | For example, | |
630 | .Dq 192.0.2.0/33 | |
631 | and | |
632 | .Dq 192.0.2.0/8 | |
633 | respectively. | |
634 | .Pp | |
30460aeb | 635 | Only a subset of keywords may be used on the lines following a |
636 | .Cm Match | |
637 | keyword. | |
638 | Available keywords are | |
5262cbfb | 639 | .Cm AllowAgentForwarding , |
30460aeb | 640 | .Cm AllowTcpForwarding , |
0b90ac93 | 641 | .Cm Banner , |
5156b1a1 | 642 | .Cm ChrootDirectory , |
30460aeb | 643 | .Cm ForceCommand , |
644 | .Cm GatewayPorts , | |
5156b1a1 | 645 | .Cm GSSAPIAuthentication , |
646 | .Cm HostbasedAuthentication , | |
0b90ac93 | 647 | .Cm KbdInteractiveAuthentication , |
648 | .Cm KerberosAuthentication , | |
5156b1a1 | 649 | .Cm MaxAuthTries , |
650 | .Cm MaxSessions , | |
0b90ac93 | 651 | .Cm PasswordAuthentication , |
5262cbfb | 652 | .Cm PermitEmptyPasswords , |
30460aeb | 653 | .Cm PermitOpen , |
e74dc197 | 654 | .Cm PermitRootLogin , |
0b90ac93 | 655 | .Cm RhostsRSAAuthentication , |
656 | .Cm RSAAuthentication , | |
30460aeb | 657 | .Cm X11DisplayOffset , |
5262cbfb | 658 | .Cm X11Forwarding |
30460aeb | 659 | and |
660 | .Cm X11UseLocalHost . | |
7e82606e | 661 | .It Cm MaxAuthTries |
662 | Specifies the maximum number of authentication attempts permitted per | |
663 | connection. | |
664 | Once the number of failures reaches half this value, | |
665 | additional failures are logged. | |
666 | The default is 6. | |
5156b1a1 | 667 | .It Cm MaxSessions |
668 | Specifies the maximum number of open sessions permitted per network connection. | |
669 | The default is 10. | |
884dc78b | 670 | .It Cm MaxStartups |
671 | Specifies the maximum number of concurrent unauthenticated connections to the | |
30460aeb | 672 | SSH daemon. |
884dc78b | 673 | Additional connections will be dropped until authentication succeeds or the |
674 | .Cm LoginGraceTime | |
675 | expires for a connection. | |
676 | The default is 10. | |
677 | .Pp | |
678 | Alternatively, random early drop can be enabled by specifying | |
679 | the three colon separated values | |
680 | .Dq start:rate:full | |
30460aeb | 681 | (e.g. "10:30:60"). |
682 | .Xr sshd 8 | |
884dc78b | 683 | will refuse connection attempts with a probability of |
684 | .Dq rate/100 | |
685 | (30%) | |
686 | if there are currently | |
687 | .Dq start | |
688 | (10) | |
689 | unauthenticated connections. | |
690 | The probability increases linearly and all connection attempts | |
691 | are refused if the number of unauthenticated connections reaches | |
692 | .Dq full | |
693 | (60). | |
694 | .It Cm PasswordAuthentication | |
695 | Specifies whether password authentication is allowed. | |
696 | The default is | |
697 | .Dq yes . | |
698 | .It Cm PermitEmptyPasswords | |
699 | When password authentication is allowed, it specifies whether the | |
700 | server allows login to accounts with empty password strings. | |
701 | The default is | |
702 | .Dq no . | |
30460aeb | 703 | .It Cm PermitOpen |
704 | Specifies the destinations to which TCP port forwarding is permitted. | |
705 | The forwarding specification must be one of the following forms: | |
706 | .Pp | |
707 | .Bl -item -offset indent -compact | |
708 | .It | |
709 | .Cm PermitOpen | |
710 | .Sm off | |
711 | .Ar host : port | |
712 | .Sm on | |
713 | .It | |
714 | .Cm PermitOpen | |
715 | .Sm off | |
716 | .Ar IPv4_addr : port | |
717 | .Sm on | |
718 | .It | |
719 | .Cm PermitOpen | |
720 | .Sm off | |
721 | .Ar \&[ IPv6_addr \&] : port | |
722 | .Sm on | |
723 | .El | |
724 | .Pp | |
725 | Multiple forwards may be specified by separating them with whitespace. | |
726 | An argument of | |
727 | .Dq any | |
728 | can be used to remove all restrictions and permit any forwarding requests. | |
729 | By default all port forwarding requests are permitted. | |
884dc78b | 730 | .It Cm PermitRootLogin |
dfddba3d | 731 | Specifies whether root can log in using |
884dc78b | 732 | .Xr ssh 1 . |
733 | The argument must be | |
734 | .Dq yes , | |
735 | .Dq without-password , | |
30460aeb | 736 | .Dq forced-commands-only , |
884dc78b | 737 | or |
738 | .Dq no . | |
739 | The default is | |
740 | .Dq yes . | |
741 | .Pp | |
742 | If this option is set to | |
30460aeb | 743 | .Dq without-password , |
dfddba3d | 744 | password authentication is disabled for root. |
884dc78b | 745 | .Pp |
746 | If this option is set to | |
30460aeb | 747 | .Dq forced-commands-only , |
884dc78b | 748 | root login with public key authentication will be allowed, |
749 | but only if the | |
750 | .Ar command | |
751 | option has been specified | |
752 | (which may be useful for taking remote backups even if root login is | |
7cac2b65 | 753 | normally not allowed). |
754 | All other authentication methods are disabled for root. | |
884dc78b | 755 | .Pp |
756 | If this option is set to | |
30460aeb | 757 | .Dq no , |
dfddba3d | 758 | root is not allowed to log in. |
08822d99 | 759 | .It Cm PermitTunnel |
760 | Specifies whether | |
761 | .Xr tun 4 | |
762 | device forwarding is allowed. | |
763 | The argument must be | |
764 | .Dq yes , | |
30460aeb | 765 | .Dq point-to-point |
766 | (layer 3), | |
08822d99 | 767 | .Dq ethernet |
30460aeb | 768 | (layer 2), or |
08822d99 | 769 | .Dq no . |
30460aeb | 770 | Specifying |
771 | .Dq yes | |
772 | permits both | |
773 | .Dq point-to-point | |
774 | and | |
775 | .Dq ethernet . | |
08822d99 | 776 | The default is |
777 | .Dq no . | |
d03f4262 | 778 | .It Cm PermitUserEnvironment |
779 | Specifies whether | |
780 | .Pa ~/.ssh/environment | |
781 | and | |
782 | .Cm environment= | |
783 | options in | |
784 | .Pa ~/.ssh/authorized_keys | |
785 | are processed by | |
30460aeb | 786 | .Xr sshd 8 . |
d03f4262 | 787 | The default is |
788 | .Dq no . | |
789 | Enabling environment processing may enable users to bypass access | |
790 | restrictions in some configurations using mechanisms such as | |
791 | .Ev LD_PRELOAD . | |
884dc78b | 792 | .It Cm PidFile |
276b07a3 | 793 | Specifies the file that contains the process ID of the |
30460aeb | 794 | SSH daemon. |
884dc78b | 795 | The default is |
796 | .Pa /var/run/sshd.pid . | |
797 | .It Cm Port | |
798 | Specifies the port number that | |
30460aeb | 799 | .Xr sshd 8 |
884dc78b | 800 | listens on. |
801 | The default is 22. | |
802 | Multiple options of this type are permitted. | |
803 | See also | |
804 | .Cm ListenAddress . | |
805 | .It Cm PrintLastLog | |
806 | Specifies whether | |
30460aeb | 807 | .Xr sshd 8 |
dfddba3d | 808 | should print the date and time of the last user login when a user logs |
809 | in interactively. | |
884dc78b | 810 | The default is |
811 | .Dq yes . | |
812 | .It Cm PrintMotd | |
813 | Specifies whether | |
30460aeb | 814 | .Xr sshd 8 |
884dc78b | 815 | should print |
816 | .Pa /etc/motd | |
817 | when a user logs in interactively. | |
818 | (On some systems it is also printed by the shell, | |
819 | .Pa /etc/profile , | |
820 | or equivalent.) | |
821 | The default is | |
822 | .Dq yes . | |
823 | .It Cm Protocol | |
824 | Specifies the protocol versions | |
30460aeb | 825 | .Xr sshd 8 |
d03f4262 | 826 | supports. |
884dc78b | 827 | The possible values are |
30460aeb | 828 | .Sq 1 |
884dc78b | 829 | and |
30460aeb | 830 | .Sq 2 . |
884dc78b | 831 | Multiple versions must be comma-separated. |
832 | The default is | |
833 | .Dq 2,1 . | |
d03f4262 | 834 | Note that the order of the protocol list does not indicate preference, |
835 | because the client selects among multiple protocol versions offered | |
836 | by the server. | |
837 | Specifying | |
838 | .Dq 2,1 | |
839 | is identical to | |
840 | .Dq 1,2 . | |
884dc78b | 841 | .It Cm PubkeyAuthentication |
842 | Specifies whether public key authentication is allowed. | |
843 | The default is | |
844 | .Dq yes . | |
845 | Note that this option applies to protocol version 2 only. | |
884dc78b | 846 | .It Cm RhostsRSAAuthentication |
847 | Specifies whether rhosts or /etc/hosts.equiv authentication together | |
848 | with successful RSA host authentication is allowed. | |
849 | The default is | |
850 | .Dq no . | |
851 | This option applies to protocol version 1 only. | |
852 | .It Cm RSAAuthentication | |
853 | Specifies whether pure RSA authentication is allowed. | |
854 | The default is | |
855 | .Dq yes . | |
856 | This option applies to protocol version 1 only. | |
857 | .It Cm ServerKeyBits | |
858 | Defines the number of bits in the ephemeral protocol version 1 server key. | |
5156b1a1 | 859 | The minimum value is 512, and the default is 1024. |
884dc78b | 860 | .It Cm StrictModes |
861 | Specifies whether | |
30460aeb | 862 | .Xr sshd 8 |
884dc78b | 863 | should check file modes and ownership of the |
864 | user's files and home directory before accepting login. | |
865 | This is normally desirable because novices sometimes accidentally leave their | |
866 | directory or files world-writable. | |
867 | The default is | |
868 | .Dq yes . | |
869 | .It Cm Subsystem | |
30460aeb | 870 | Configures an external subsystem (e.g. file transfer daemon). |
871 | Arguments should be a subsystem name and a command (with optional arguments) | |
872 | to execute upon subsystem request. | |
e74dc197 | 873 | .Pp |
884dc78b | 874 | The command |
875 | .Xr sftp-server 8 | |
876 | implements the | |
877 | .Dq sftp | |
878 | file transfer subsystem. | |
e74dc197 | 879 | .Pp |
880 | Alternately the name | |
881 | .Dq internal-sftp | |
882 | implements an in-process | |
883 | .Dq sftp | |
884 | server. | |
885 | This may simplify configurations using | |
886 | .Cm ChrootDirectory | |
887 | to force a different filesystem root on clients. | |
888 | .Pp | |
884dc78b | 889 | By default no subsystems are defined. |
890 | Note that this option applies to protocol version 2 only. | |
891 | .It Cm SyslogFacility | |
892 | Gives the facility code that is used when logging messages from | |
30460aeb | 893 | .Xr sshd 8 . |
884dc78b | 894 | The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2, |
895 | LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7. | |
896 | The default is AUTH. | |
540d72c3 | 897 | .It Cm TCPKeepAlive |
898 | Specifies whether the system should send TCP keepalive messages to the | |
899 | other side. | |
900 | If they are sent, death of the connection or crash of one | |
901 | of the machines will be properly noticed. | |
902 | However, this means that | |
903 | connections will die if the route is down temporarily, and some people | |
904 | find it annoying. | |
905 | On the other hand, if TCP keepalives are not sent, | |
906 | sessions may hang indefinitely on the server, leaving | |
907 | .Dq ghost | |
908 | users and consuming server resources. | |
909 | .Pp | |
910 | The default is | |
911 | .Dq yes | |
912 | (to send TCP keepalive messages), and the server will notice | |
913 | if the network goes down or the client host crashes. | |
914 | This avoids infinitely hanging sessions. | |
915 | .Pp | |
916 | To disable TCP keepalive messages, the value should be set to | |
917 | .Dq no . | |
7cac2b65 | 918 | .It Cm UseDNS |
919 | Specifies whether | |
30460aeb | 920 | .Xr sshd 8 |
8b32eddc | 921 | should look up the remote host name and check that |
7cac2b65 | 922 | the resolved host name for the remote IP address maps back to the |
923 | very same IP address. | |
924 | The default is | |
925 | .Dq yes . | |
884dc78b | 926 | .It Cm UseLogin |
927 | Specifies whether | |
928 | .Xr login 1 | |
929 | is used for interactive login sessions. | |
930 | The default is | |
931 | .Dq no . | |
932 | Note that | |
933 | .Xr login 1 | |
934 | is never used for remote command execution. | |
935 | Note also, that if this is enabled, | |
936 | .Cm X11Forwarding | |
937 | will be disabled because | |
938 | .Xr login 1 | |
939 | does not know how to handle | |
940 | .Xr xauth 1 | |
bfe49944 | 941 | cookies. |
942 | If | |
884dc78b | 943 | .Cm UsePrivilegeSeparation |
944 | is specified, it will be disabled after authentication. | |
7cac2b65 | 945 | .It Cm UsePAM |
7e82606e | 946 | Enables the Pluggable Authentication Module interface. |
947 | If set to | |
948 | .Dq yes | |
949 | this will enable PAM authentication using | |
950 | .Cm ChallengeResponseAuthentication | |
30460aeb | 951 | and |
952 | .Cm PasswordAuthentication | |
953 | in addition to PAM account and session module processing for all | |
954 | authentication types. | |
7e82606e | 955 | .Pp |
956 | Because PAM challenge-response authentication usually serves an equivalent | |
957 | role to password authentication, you should disable either | |
958 | .Cm PasswordAuthentication | |
959 | or | |
960 | .Cm ChallengeResponseAuthentication. | |
961 | .Pp | |
962 | If | |
963 | .Cm UsePAM | |
964 | is enabled, you will not be able to run | |
965 | .Xr sshd 8 | |
966 | as a non-root user. | |
967 | The default is | |
540d72c3 | 968 | .Dq no . |
d037a8b0 | 969 | .It Cm PermitPAMUserChange |
970 | If set to | |
971 | .Dq yes | |
972 | this will enable PAM authentication to change the name of the user being | |
973 | authenticated. The default is | |
974 | .Dq no . | |
884dc78b | 975 | .It Cm UsePrivilegeSeparation |
976 | Specifies whether | |
30460aeb | 977 | .Xr sshd 8 |
884dc78b | 978 | separates privileges by creating an unprivileged child process |
bfe49944 | 979 | to deal with incoming network traffic. |
980 | After successful authentication, another process will be created that has | |
981 | the privilege of the authenticated user. | |
982 | The goal of privilege separation is to prevent privilege | |
884dc78b | 983 | escalation by containing any corruption within the unprivileged processes. |
984 | The default is | |
985 | .Dq yes . | |
884dc78b | 986 | .It Cm X11DisplayOffset |
987 | Specifies the first display number available for | |
30460aeb | 988 | .Xr sshd 8 Ns 's |
884dc78b | 989 | X11 forwarding. |
30460aeb | 990 | This prevents sshd from interfering with real X11 servers. |
884dc78b | 991 | The default is 10. |
992 | .It Cm X11Forwarding | |
993 | Specifies whether X11 forwarding is permitted. | |
d03f4262 | 994 | The argument must be |
995 | .Dq yes | |
996 | or | |
997 | .Dq no . | |
884dc78b | 998 | The default is |
999 | .Dq no . | |
d03f4262 | 1000 | .Pp |
1001 | When X11 forwarding is enabled, there may be additional exposure to | |
1002 | the server and to client displays if the | |
30460aeb | 1003 | .Xr sshd 8 |
d03f4262 | 1004 | proxy display is configured to listen on the wildcard address (see |
1005 | .Cm X11UseLocalhost | |
30460aeb | 1006 | below), though this is not the default. |
d03f4262 | 1007 | Additionally, the authentication spoofing and authentication data |
1008 | verification and substitution occur on the client side. | |
1009 | The security risk of using X11 forwarding is that the client's X11 | |
30460aeb | 1010 | display server may be exposed to attack when the SSH client requests |
d03f4262 | 1011 | forwarding (see the warnings for |
1012 | .Cm ForwardX11 | |
1013 | in | |
7cac2b65 | 1014 | .Xr ssh_config 5 ) . |
d03f4262 | 1015 | A system administrator may have a stance in which they want to |
1016 | protect clients that may expose themselves to attack by unwittingly | |
1017 | requesting X11 forwarding, which can warrant a | |
1018 | .Dq no | |
1019 | setting. | |
1020 | .Pp | |
1021 | Note that disabling X11 forwarding does not prevent users from | |
1022 | forwarding X11 traffic, as users can always install their own forwarders. | |
884dc78b | 1023 | X11 forwarding is automatically disabled if |
1024 | .Cm UseLogin | |
1025 | is enabled. | |
1026 | .It Cm X11UseLocalhost | |
1027 | Specifies whether | |
30460aeb | 1028 | .Xr sshd 8 |
884dc78b | 1029 | should bind the X11 forwarding server to the loopback address or to |
bfe49944 | 1030 | the wildcard address. |
1031 | By default, | |
30460aeb | 1032 | sshd binds the forwarding server to the loopback address and sets the |
884dc78b | 1033 | hostname part of the |
1034 | .Ev DISPLAY | |
1035 | environment variable to | |
1036 | .Dq localhost . | |
d03f4262 | 1037 | This prevents remote hosts from connecting to the proxy display. |
884dc78b | 1038 | However, some older X11 clients may not function with this |
1039 | configuration. | |
1040 | .Cm X11UseLocalhost | |
1041 | may be set to | |
1042 | .Dq no | |
1043 | to specify that the forwarding server should be bound to the wildcard | |
1044 | address. | |
1045 | The argument must be | |
1046 | .Dq yes | |
1047 | or | |
1048 | .Dq no . | |
1049 | The default is | |
1050 | .Dq yes . | |
1051 | .It Cm XAuthLocation | |
d03f4262 | 1052 | Specifies the full pathname of the |
884dc78b | 1053 | .Xr xauth 1 |
1054 | program. | |
1055 | The default is | |
1056 | .Pa /usr/X11R6/bin/xauth . | |
1057 | .El | |
30460aeb | 1058 | .Sh TIME FORMATS |
1059 | .Xr sshd 8 | |
884dc78b | 1060 | command-line arguments and configuration file options that specify time |
1061 | may be expressed using a sequence of the form: | |
1062 | .Sm off | |
d03f4262 | 1063 | .Ar time Op Ar qualifier , |
884dc78b | 1064 | .Sm on |
1065 | where | |
1066 | .Ar time | |
1067 | is a positive integer value and | |
1068 | .Ar qualifier | |
1069 | is one of the following: | |
1070 | .Pp | |
1071 | .Bl -tag -width Ds -compact -offset indent | |
30460aeb | 1072 | .It Aq Cm none |
884dc78b | 1073 | seconds |
1074 | .It Cm s | Cm S | |
1075 | seconds | |
1076 | .It Cm m | Cm M | |
1077 | minutes | |
1078 | .It Cm h | Cm H | |
1079 | hours | |
1080 | .It Cm d | Cm D | |
1081 | days | |
1082 | .It Cm w | Cm W | |
1083 | weeks | |
1084 | .El | |
1085 | .Pp | |
1086 | Each member of the sequence is added together to calculate | |
1087 | the total time value. | |
1088 | .Pp | |
1089 | Time format examples: | |
1090 | .Pp | |
1091 | .Bl -tag -width Ds -compact -offset indent | |
1092 | .It 600 | |
1093 | 600 seconds (10 minutes) | |
1094 | .It 10m | |
1095 | 10 minutes | |
1096 | .It 1h30m | |
1097 | 1 hour 30 minutes (90 minutes) | |
1098 | .El | |
1099 | .Sh FILES | |
1100 | .Bl -tag -width Ds | |
1101 | .It Pa /etc/ssh/sshd_config | |
1102 | Contains configuration data for | |
30460aeb | 1103 | .Xr sshd 8 . |
884dc78b | 1104 | This file should be writable by root only, but it is recommended |
1105 | (though not necessary) that it be world-readable. | |
1106 | .El | |
7cac2b65 | 1107 | .Sh SEE ALSO |
1108 | .Xr sshd 8 | |
884dc78b | 1109 | .Sh AUTHORS |
1110 | OpenSSH is a derivative of the original and free | |
1111 | ssh 1.2.12 release by Tatu Ylonen. | |
1112 | Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, | |
1113 | Theo de Raadt and Dug Song | |
1114 | removed many bugs, re-added newer features and | |
1115 | created OpenSSH. | |
1116 | Markus Friedl contributed the support for SSH | |
1117 | protocol versions 1.5 and 2.0. | |
1118 | Niels Provos and Markus Friedl contributed support | |
1119 | for privilege separation. |