Annotation of src/usr.bin/ssh/sshd_config.5, Revision 1.24
1.1 stevesk 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.
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1.24 ! markus 37: .\" $OpenBSD: sshd_config.5,v 1.23 2003/08/22 10:56:09 markus Exp $
1.1 stevesk 38: .Dd September 25, 1999
39: .Dt SSHD_CONFIG 5
40: .Os
41: .Sh NAME
42: .Nm sshd_config
43: .Nd OpenSSH SSH daemon configuration file
44: .Sh SYNOPSIS
45: .Bl -tag -width Ds -compact
46: .It Pa /etc/ssh/sshd_config
47: .El
48: .Sh DESCRIPTION
49: .Nm sshd
50: reads configuration data from
51: .Pa /etc/ssh/sshd_config
52: (or the file specified with
53: .Fl f
54: on the command line).
55: The file contains keyword-argument pairs, one per line.
56: Lines starting with
57: .Ql #
58: and empty lines are interpreted as comments.
59: .Pp
60: The possible
61: keywords and their meanings are as follows (note that
62: keywords are case-insensitive and arguments are case-sensitive):
63: .Bl -tag -width Ds
64: .It Cm AllowGroups
65: This keyword can be followed by a list of group name patterns, separated
66: by spaces.
67: If specified, login is allowed only for users whose primary
68: group or supplementary group list matches one of the patterns.
69: .Ql \&*
70: and
1.16 mouring 71: .Ql \&?
1.1 stevesk 72: can be used as
73: wildcards in the patterns.
74: Only group names are valid; a numerical group ID is not recognized.
75: By default, login is allowed for all groups.
76: .Pp
77: .It Cm AllowTcpForwarding
78: Specifies whether TCP forwarding is permitted.
79: The default is
80: .Dq yes .
81: Note that disabling TCP forwarding does not improve security unless
82: users are also denied shell access, as they can always install their
83: own forwarders.
84: .Pp
85: .It Cm AllowUsers
86: This keyword can be followed by a list of user name patterns, separated
87: by spaces.
1.14 jmc 88: If specified, login is allowed only for user names that
1.1 stevesk 89: match one of the patterns.
90: .Ql \&*
91: and
1.16 mouring 92: .Ql \&?
1.1 stevesk 93: can be used as
94: wildcards in the patterns.
95: Only user names are valid; a numerical user ID is not recognized.
96: By default, login is allowed for all users.
97: If the pattern takes the form USER@HOST then USER and HOST
98: are separately checked, restricting logins to particular
99: users from particular hosts.
100: .Pp
101: .It Cm AuthorizedKeysFile
102: Specifies the file that contains the public keys that can be used
103: for user authentication.
104: .Cm AuthorizedKeysFile
105: may contain tokens of the form %T which are substituted during connection
1.17 jmc 106: set-up.
107: The following tokens are defined: %% is replaced by a literal '%',
1.1 stevesk 108: %h is replaced by the home directory of the user being authenticated and
109: %u is replaced by the username of that user.
110: After expansion,
111: .Cm AuthorizedKeysFile
112: is taken to be an absolute path or one relative to the user's home
113: directory.
114: The default is
115: .Dq .ssh/authorized_keys .
116: .It Cm Banner
117: In some jurisdictions, sending a warning message before authentication
118: may be relevant for getting legal protection.
119: The contents of the specified file are sent to the remote user before
120: authentication is allowed.
121: This option is only available for protocol version 2.
122: By default, no banner is displayed.
123: .Pp
124: .It Cm ChallengeResponseAuthentication
125: Specifies whether challenge response authentication is allowed.
126: All authentication styles from
127: .Xr login.conf 5
128: are supported.
129: The default is
130: .Dq yes .
131: .It Cm Ciphers
132: Specifies the ciphers allowed for protocol version 2.
133: Multiple ciphers must be comma-separated.
134: The default is
135: .Pp
136: .Bd -literal
137: ``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,
1.20 djm 138: aes192-cbc,aes256-cbc,aes128-ctr,aes192-ctr,aes256-ctr''
1.1 stevesk 139: .Ed
140: .It Cm ClientAliveInterval
141: Sets a timeout interval in seconds after which if no data has been received
142: from the client,
143: .Nm sshd
144: will send a message through the encrypted
145: channel to request a response from the client.
146: The default
147: is 0, indicating that these messages will not be sent to the client.
148: This option applies to protocol version 2 only.
149: .It Cm ClientAliveCountMax
150: Sets the number of client alive messages (see above) which may be
151: sent without
152: .Nm sshd
1.17 jmc 153: receiving any messages back from the client.
154: If this threshold is reached while client alive messages are being sent,
1.1 stevesk 155: .Nm sshd
1.17 jmc 156: will disconnect the client, terminating the session.
157: It is important to note that the use of client alive messages is very
158: different from
1.1 stevesk 159: .Cm KeepAlive
1.17 jmc 160: (below).
161: The client alive messages are sent through the encrypted channel
162: and therefore will not be spoofable.
163: The TCP keepalive option enabled by
1.1 stevesk 164: .Cm KeepAlive
1.17 jmc 165: is spoofable.
166: The client alive mechanism is valuable when the client or
1.1 stevesk 167: server depend on knowing when a connection has become inactive.
168: .Pp
1.17 jmc 169: The default value is 3.
170: If
1.1 stevesk 171: .Cm ClientAliveInterval
172: (above) is set to 15, and
173: .Cm ClientAliveCountMax
174: is left at the default, unresponsive ssh clients
175: will be disconnected after approximately 45 seconds.
1.3 markus 176: .It Cm Compression
177: Specifies whether compression is allowed.
178: The argument must be
179: .Dq yes
180: or
181: .Dq no .
182: The default is
183: .Dq yes .
1.1 stevesk 184: .It Cm DenyGroups
185: This keyword can be followed by a list of group name patterns, separated
186: by spaces.
187: Login is disallowed for users whose primary group or supplementary
188: group list matches one of the patterns.
189: .Ql \&*
190: and
1.16 mouring 191: .Ql \&?
1.1 stevesk 192: can be used as
193: wildcards in the patterns.
194: Only group names are valid; a numerical group ID is not recognized.
195: By default, login is allowed for all groups.
196: .Pp
197: .It Cm DenyUsers
198: This keyword can be followed by a list of user name patterns, separated
199: by spaces.
200: Login is disallowed for user names that match one of the patterns.
201: .Ql \&*
202: and
1.16 mouring 203: .Ql \&?
1.1 stevesk 204: can be used as wildcards in the patterns.
205: Only user names are valid; a numerical user ID is not recognized.
206: By default, login is allowed for all users.
207: If the pattern takes the form USER@HOST then USER and HOST
208: are separately checked, restricting logins to particular
209: users from particular hosts.
210: .It Cm GatewayPorts
211: Specifies whether remote hosts are allowed to connect to ports
212: forwarded for the client.
213: By default,
214: .Nm sshd
1.15 jmc 215: binds remote port forwardings to the loopback address.
216: This prevents other remote hosts from connecting to forwarded ports.
1.1 stevesk 217: .Cm GatewayPorts
218: can be used to specify that
219: .Nm sshd
220: should bind remote port forwardings to the wildcard address,
221: thus allowing remote hosts to connect to forwarded ports.
222: The argument must be
223: .Dq yes
224: or
225: .Dq no .
226: The default is
227: .Dq no .
1.23 markus 228: .It Cm GSSAPIAuthentication
229: Specifies whether authentication based on GSSAPI may be used, either using
230: the result of a successful key exchange, or using GSSAPI user
231: authentication.
232: The default is
233: .Dq no .
234: Note that this option applies to protocol version 2 only.
235: .It Cm GSSAPICleanupCredentials
236: Specifies whether to automatically destroy the user's credentials cache
237: on logout.
238: The default is
239: .Dq yes .
240: Note that this option applies to protocol version 2 only.
1.1 stevesk 241: .It Cm HostbasedAuthentication
242: Specifies whether rhosts or /etc/hosts.equiv authentication together
243: with successful public key client host authentication is allowed
244: (hostbased authentication).
245: This option is similar to
246: .Cm RhostsRSAAuthentication
247: and applies to protocol version 2 only.
248: The default is
249: .Dq no .
250: .It Cm HostKey
251: Specifies a file containing a private host key
252: used by SSH.
253: The default is
254: .Pa /etc/ssh/ssh_host_key
255: for protocol version 1, and
256: .Pa /etc/ssh/ssh_host_rsa_key
257: and
258: .Pa /etc/ssh/ssh_host_dsa_key
259: for protocol version 2.
260: Note that
261: .Nm sshd
262: will refuse to use a file if it is group/world-accessible.
263: It is possible to have multiple host key files.
264: .Dq rsa1
265: keys are used for version 1 and
266: .Dq dsa
267: or
268: .Dq rsa
269: are used for version 2 of the SSH protocol.
270: .It Cm IgnoreRhosts
271: Specifies that
272: .Pa .rhosts
273: and
274: .Pa .shosts
275: files will not be used in
276: .Cm RhostsRSAAuthentication
277: or
278: .Cm HostbasedAuthentication .
279: .Pp
280: .Pa /etc/hosts.equiv
281: and
282: .Pa /etc/shosts.equiv
283: are still used.
284: The default is
285: .Dq yes .
286: .It Cm IgnoreUserKnownHosts
287: Specifies whether
288: .Nm sshd
289: should ignore the user's
290: .Pa $HOME/.ssh/known_hosts
291: during
292: .Cm RhostsRSAAuthentication
293: or
294: .Cm HostbasedAuthentication .
295: The default is
296: .Dq no .
297: .It Cm KeepAlive
298: Specifies whether the system should send TCP keepalive messages to the
299: other side.
300: If they are sent, death of the connection or crash of one
301: of the machines will be properly noticed.
302: However, this means that
303: connections will die if the route is down temporarily, and some people
304: find it annoying.
305: On the other hand, if keepalives are not sent,
306: sessions may hang indefinitely on the server, leaving
307: .Dq ghost
308: users and consuming server resources.
309: .Pp
310: The default is
311: .Dq yes
312: (to send keepalives), and the server will notice
313: if the network goes down or the client host crashes.
314: This avoids infinitely hanging sessions.
315: .Pp
316: To disable keepalives, the value should be set to
317: .Dq no .
318: .It Cm KerberosAuthentication
1.24 ! markus 319: Specifies whether the password provided by the user for
1.1 stevesk 320: .Cm PasswordAuthentication
1.24 ! markus 321: will be validated through the Kerberos KDC.
1.1 stevesk 322: To use this option, the server needs a
323: Kerberos servtab which allows the verification of the KDC's identity.
324: Default is
325: .Dq no .
326: .It Cm KerberosOrLocalPasswd
327: If set then if password authentication through Kerberos fails then
328: the password will be validated via any additional local mechanism
329: such as
330: .Pa /etc/passwd .
331: Default is
332: .Dq yes .
333: .It Cm KerberosTicketCleanup
334: Specifies whether to automatically destroy the user's ticket cache
335: file on logout.
336: Default is
337: .Dq yes .
338: .It Cm KeyRegenerationInterval
339: In protocol version 1, the ephemeral server key is automatically regenerated
340: after this many seconds (if it has been used).
341: The purpose of regeneration is to prevent
342: decrypting captured sessions by later breaking into the machine and
343: stealing the keys.
344: The key is never stored anywhere.
345: If the value is 0, the key is never regenerated.
346: The default is 3600 (seconds).
347: .It Cm ListenAddress
348: Specifies the local addresses
349: .Nm sshd
350: should listen on.
351: The following forms may be used:
352: .Pp
353: .Bl -item -offset indent -compact
354: .It
355: .Cm ListenAddress
356: .Sm off
357: .Ar host No | Ar IPv4_addr No | Ar IPv6_addr
358: .Sm on
359: .It
360: .Cm ListenAddress
361: .Sm off
362: .Ar host No | Ar IPv4_addr No : Ar port
363: .Sm on
364: .It
365: .Cm ListenAddress
366: .Sm off
367: .Oo
368: .Ar host No | Ar IPv6_addr Oc : Ar port
369: .Sm on
370: .El
371: .Pp
372: If
373: .Ar port
374: is not specified,
375: .Nm sshd
376: will listen on the address and all prior
377: .Cm Port
1.17 jmc 378: options specified.
379: The default is to listen on all local addresses.
1.15 jmc 380: Multiple
1.1 stevesk 381: .Cm ListenAddress
1.17 jmc 382: options are permitted.
383: Additionally, any
1.1 stevesk 384: .Cm Port
385: options must precede this option for non port qualified addresses.
386: .It Cm LoginGraceTime
387: The server disconnects after this time if the user has not
388: successfully logged in.
389: If the value is 0, there is no time limit.
1.12 stevesk 390: The default is 120 seconds.
1.1 stevesk 391: .It Cm LogLevel
392: Gives the verbosity level that is used when logging messages from
393: .Nm sshd .
394: The possible values are:
395: QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2 and DEBUG3.
1.15 jmc 396: The default is INFO.
397: DEBUG and DEBUG1 are equivalent.
398: DEBUG2 and DEBUG3 each specify higher levels of debugging output.
399: Logging with a DEBUG level violates the privacy of users and is not recommended.
1.1 stevesk 400: .It Cm MACs
401: Specifies the available MAC (message authentication code) algorithms.
402: The MAC algorithm is used in protocol version 2
403: for data integrity protection.
404: Multiple algorithms must be comma-separated.
405: The default is
406: .Dq hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 .
407: .It Cm MaxStartups
408: Specifies the maximum number of concurrent unauthenticated connections to the
409: .Nm sshd
410: daemon.
411: Additional connections will be dropped until authentication succeeds or the
412: .Cm LoginGraceTime
413: expires for a connection.
414: The default is 10.
415: .Pp
416: Alternatively, random early drop can be enabled by specifying
417: the three colon separated values
418: .Dq start:rate:full
419: (e.g., "10:30:60").
420: .Nm sshd
421: will refuse connection attempts with a probability of
422: .Dq rate/100
423: (30%)
424: if there are currently
425: .Dq start
426: (10)
427: unauthenticated connections.
428: The probability increases linearly and all connection attempts
429: are refused if the number of unauthenticated connections reaches
430: .Dq full
431: (60).
432: .It Cm PasswordAuthentication
433: Specifies whether password authentication is allowed.
434: The default is
435: .Dq yes .
436: .It Cm PermitEmptyPasswords
437: When password authentication is allowed, it specifies whether the
438: server allows login to accounts with empty password strings.
439: The default is
440: .Dq no .
441: .It Cm PermitRootLogin
442: Specifies whether root can login using
443: .Xr ssh 1 .
444: The argument must be
445: .Dq yes ,
446: .Dq without-password ,
447: .Dq forced-commands-only
448: or
449: .Dq no .
450: The default is
451: .Dq yes .
452: .Pp
453: If this option is set to
454: .Dq without-password
455: password authentication is disabled for root.
456: .Pp
457: If this option is set to
458: .Dq forced-commands-only
459: root login with public key authentication will be allowed,
460: but only if the
461: .Ar command
462: option has been specified
463: (which may be useful for taking remote backups even if root login is
1.17 jmc 464: normally not allowed).
465: All other authentication methods are disabled for root.
1.1 stevesk 466: .Pp
467: If this option is set to
468: .Dq no
469: root is not allowed to login.
1.6 markus 470: .It Cm PermitUserEnvironment
471: Specifies whether
472: .Pa ~/.ssh/environment
1.9 stevesk 473: and
1.6 markus 474: .Cm environment=
475: options in
476: .Pa ~/.ssh/authorized_keys
1.9 stevesk 477: are processed by
478: .Nm sshd .
1.6 markus 479: The default is
480: .Dq no .
1.9 stevesk 481: Enabling environment processing may enable users to bypass access
482: restrictions in some configurations using mechanisms such as
483: .Ev LD_PRELOAD .
1.1 stevesk 484: .It Cm PidFile
1.4 stevesk 485: Specifies the file that contains the process ID of the
1.1 stevesk 486: .Nm sshd
487: daemon.
488: The default is
489: .Pa /var/run/sshd.pid .
490: .It Cm Port
491: Specifies the port number that
492: .Nm sshd
493: listens on.
494: The default is 22.
495: Multiple options of this type are permitted.
496: See also
497: .Cm ListenAddress .
498: .It Cm PrintLastLog
499: Specifies whether
500: .Nm sshd
501: should print the date and time when the user last logged in.
502: The default is
503: .Dq yes .
504: .It Cm PrintMotd
505: Specifies whether
506: .Nm sshd
507: should print
508: .Pa /etc/motd
509: when a user logs in interactively.
510: (On some systems it is also printed by the shell,
511: .Pa /etc/profile ,
512: or equivalent.)
513: The default is
514: .Dq yes .
515: .It Cm Protocol
516: Specifies the protocol versions
517: .Nm sshd
1.5 stevesk 518: supports.
1.1 stevesk 519: The possible values are
520: .Dq 1
521: and
522: .Dq 2 .
523: Multiple versions must be comma-separated.
524: The default is
525: .Dq 2,1 .
1.5 stevesk 526: Note that the order of the protocol list does not indicate preference,
527: because the client selects among multiple protocol versions offered
528: by the server.
529: Specifying
530: .Dq 2,1
531: is identical to
532: .Dq 1,2 .
1.1 stevesk 533: .It Cm PubkeyAuthentication
534: Specifies whether public key authentication is allowed.
535: The default is
536: .Dq yes .
537: Note that this option applies to protocol version 2 only.
538: .Cm RhostsRSAAuthentication
539: should be used
540: instead, because it performs RSA-based host authentication in addition
541: to normal rhosts or /etc/hosts.equiv authentication.
542: The default is
543: .Dq no .
544: This option applies to protocol version 1 only.
545: .It Cm RhostsRSAAuthentication
546: Specifies whether rhosts or /etc/hosts.equiv authentication together
547: with successful RSA host authentication is allowed.
548: The default is
549: .Dq no .
550: This option applies to protocol version 1 only.
551: .It Cm RSAAuthentication
552: Specifies whether pure RSA authentication is allowed.
553: The default is
554: .Dq yes .
555: This option applies to protocol version 1 only.
556: .It Cm ServerKeyBits
557: Defines the number of bits in the ephemeral protocol version 1 server key.
558: The minimum value is 512, and the default is 768.
559: .It Cm StrictModes
560: Specifies whether
561: .Nm sshd
562: should check file modes and ownership of the
563: user's files and home directory before accepting login.
564: This is normally desirable because novices sometimes accidentally leave their
565: directory or files world-writable.
566: The default is
567: .Dq yes .
568: .It Cm Subsystem
569: Configures an external subsystem (e.g., file transfer daemon).
570: Arguments should be a subsystem name and a command to execute upon subsystem
571: request.
572: The command
573: .Xr sftp-server 8
574: implements the
575: .Dq sftp
576: file transfer subsystem.
577: By default no subsystems are defined.
578: Note that this option applies to protocol version 2 only.
579: .It Cm SyslogFacility
580: Gives the facility code that is used when logging messages from
581: .Nm sshd .
582: The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2,
583: LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7.
584: The default is AUTH.
1.18 markus 585: .It Cm UseDNS
586: Specifies whether
587: .Nm sshd
588: should lookup the remote host name and check that
589: the resolved host name for the remote IP address maps back to the
590: very same IP address.
591: The default is
592: .Dq yes .
1.1 stevesk 593: .It Cm UseLogin
594: Specifies whether
595: .Xr login 1
596: is used for interactive login sessions.
597: The default is
598: .Dq no .
599: Note that
600: .Xr login 1
601: is never used for remote command execution.
602: Note also, that if this is enabled,
603: .Cm X11Forwarding
604: will be disabled because
605: .Xr login 1
606: does not know how to handle
607: .Xr xauth 1
1.15 jmc 608: cookies.
609: If
1.1 stevesk 610: .Cm UsePrivilegeSeparation
611: is specified, it will be disabled after authentication.
612: .It Cm UsePrivilegeSeparation
613: Specifies whether
614: .Nm sshd
1.2 stevesk 615: separates privileges by creating an unprivileged child process
1.15 jmc 616: to deal with incoming network traffic.
617: After successful authentication, another process will be created that has
618: the privilege of the authenticated user.
619: The goal of privilege separation is to prevent privilege
1.1 stevesk 620: escalation by containing any corruption within the unprivileged processes.
621: The default is
622: .Dq yes .
623: .It Cm X11DisplayOffset
624: Specifies the first display number available for
625: .Nm sshd Ns 's
626: X11 forwarding.
627: This prevents
628: .Nm sshd
629: from interfering with real X11 servers.
630: The default is 10.
631: .It Cm X11Forwarding
632: Specifies whether X11 forwarding is permitted.
1.13 stevesk 633: The argument must be
634: .Dq yes
635: or
636: .Dq no .
1.1 stevesk 637: The default is
638: .Dq no .
1.13 stevesk 639: .Pp
640: When X11 forwarding is enabled, there may be additional exposure to
641: the server and to client displays if the
642: .Nm sshd
643: proxy display is configured to listen on the wildcard address (see
644: .Cm X11UseLocalhost
645: below), however this is not the default.
646: Additionally, the authentication spoofing and authentication data
647: verification and substitution occur on the client side.
648: The security risk of using X11 forwarding is that the client's X11
649: display server may be exposed to attack when the ssh client requests
650: forwarding (see the warnings for
651: .Cm ForwardX11
652: in
1.19 jmc 653: .Xr ssh_config 5 ) .
1.13 stevesk 654: A system administrator may have a stance in which they want to
655: protect clients that may expose themselves to attack by unwittingly
656: requesting X11 forwarding, which can warrant a
657: .Dq no
658: setting.
659: .Pp
660: Note that disabling X11 forwarding does not prevent users from
661: forwarding X11 traffic, as users can always install their own forwarders.
1.1 stevesk 662: X11 forwarding is automatically disabled if
663: .Cm UseLogin
664: is enabled.
665: .It Cm X11UseLocalhost
666: Specifies whether
667: .Nm sshd
668: should bind the X11 forwarding server to the loopback address or to
1.15 jmc 669: the wildcard address.
670: By default,
1.1 stevesk 671: .Nm sshd
672: binds the forwarding server to the loopback address and sets the
673: hostname part of the
674: .Ev DISPLAY
675: environment variable to
676: .Dq localhost .
1.8 stevesk 677: This prevents remote hosts from connecting to the proxy display.
1.1 stevesk 678: However, some older X11 clients may not function with this
679: configuration.
680: .Cm X11UseLocalhost
681: may be set to
682: .Dq no
683: to specify that the forwarding server should be bound to the wildcard
684: address.
685: The argument must be
686: .Dq yes
687: or
688: .Dq no .
689: The default is
690: .Dq yes .
691: .It Cm XAuthLocation
1.11 stevesk 692: Specifies the full pathname of the
1.1 stevesk 693: .Xr xauth 1
694: program.
695: The default is
696: .Pa /usr/X11R6/bin/xauth .
697: .El
698: .Ss Time Formats
699: .Nm sshd
700: command-line arguments and configuration file options that specify time
701: may be expressed using a sequence of the form:
702: .Sm off
1.7 stevesk 703: .Ar time Op Ar qualifier ,
1.1 stevesk 704: .Sm on
705: where
706: .Ar time
707: is a positive integer value and
708: .Ar qualifier
709: is one of the following:
710: .Pp
711: .Bl -tag -width Ds -compact -offset indent
712: .It Cm <none>
713: seconds
714: .It Cm s | Cm S
715: seconds
716: .It Cm m | Cm M
717: minutes
718: .It Cm h | Cm H
719: hours
720: .It Cm d | Cm D
721: days
722: .It Cm w | Cm W
723: weeks
724: .El
725: .Pp
726: Each member of the sequence is added together to calculate
727: the total time value.
728: .Pp
729: Time format examples:
730: .Pp
731: .Bl -tag -width Ds -compact -offset indent
732: .It 600
733: 600 seconds (10 minutes)
734: .It 10m
735: 10 minutes
736: .It 1h30m
737: 1 hour 30 minutes (90 minutes)
738: .El
739: .Sh FILES
740: .Bl -tag -width Ds
741: .It Pa /etc/ssh/sshd_config
742: Contains configuration data for
743: .Nm sshd .
744: This file should be writable by root only, but it is recommended
745: (though not necessary) that it be world-readable.
746: .El
1.19 jmc 747: .Sh SEE ALSO
748: .Xr sshd 8
1.1 stevesk 749: .Sh AUTHORS
750: OpenSSH is a derivative of the original and free
751: ssh 1.2.12 release by Tatu Ylonen.
752: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
753: Theo de Raadt and Dug Song
754: removed many bugs, re-added newer features and
755: created OpenSSH.
756: Markus Friedl contributed the support for SSH
757: protocol versions 1.5 and 2.0.
758: Niels Provos and Markus Friedl contributed support
759: for privilege separation.