Annotation of src/usr.bin/ssh/sshd_config.5, Revision 1.15
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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1.15 ! jmc 37: .\" $OpenBSD: sshd_config.5,v 1.14 2003/01/23 08:58:47 jmc 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 AFSTokenPassing
65: Specifies whether an AFS token may be forwarded to the server.
66: Default is
67: .Dq no .
68: .It Cm AllowGroups
69: This keyword can be followed by a list of group name patterns, separated
70: by spaces.
71: If specified, login is allowed only for users whose primary
72: group or supplementary group list matches one of the patterns.
73: .Ql \&*
74: and
75: .Ql ?
76: can be used as
77: wildcards in the patterns.
78: Only group names are valid; a numerical group ID is not recognized.
79: By default, login is allowed for all groups.
80: .Pp
81: .It Cm AllowTcpForwarding
82: Specifies whether TCP forwarding is permitted.
83: The default is
84: .Dq yes .
85: Note that disabling TCP forwarding does not improve security unless
86: users are also denied shell access, as they can always install their
87: own forwarders.
88: .Pp
89: .It Cm AllowUsers
90: This keyword can be followed by a list of user name patterns, separated
91: by spaces.
1.14 jmc 92: If specified, login is allowed only for user names that
1.1 stevesk 93: match one of the patterns.
94: .Ql \&*
95: and
96: .Ql ?
97: can be used as
98: wildcards in the patterns.
99: Only user names are valid; a numerical user ID is not recognized.
100: By default, login is allowed for all users.
101: If the pattern takes the form USER@HOST then USER and HOST
102: are separately checked, restricting logins to particular
103: users from particular hosts.
104: .Pp
105: .It Cm AuthorizedKeysFile
106: Specifies the file that contains the public keys that can be used
107: for user authentication.
108: .Cm AuthorizedKeysFile
109: may contain tokens of the form %T which are substituted during connection
110: set-up. The following tokens are defined: %% is replaced by a literal '%',
111: %h is replaced by the home directory of the user being authenticated and
112: %u is replaced by the username of that user.
113: After expansion,
114: .Cm AuthorizedKeysFile
115: is taken to be an absolute path or one relative to the user's home
116: directory.
117: The default is
118: .Dq .ssh/authorized_keys .
119: .It Cm Banner
120: In some jurisdictions, sending a warning message before authentication
121: may be relevant for getting legal protection.
122: The contents of the specified file are sent to the remote user before
123: authentication is allowed.
124: This option is only available for protocol version 2.
125: By default, no banner is displayed.
126: .Pp
127: .It Cm ChallengeResponseAuthentication
128: Specifies whether challenge response authentication is allowed.
129: All authentication styles from
130: .Xr login.conf 5
131: are supported.
132: The default is
133: .Dq yes .
134: .It Cm Ciphers
135: Specifies the ciphers allowed for protocol version 2.
136: Multiple ciphers must be comma-separated.
137: The default is
138: .Pp
139: .Bd -literal
140: ``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,
141: aes192-cbc,aes256-cbc''
142: .Ed
143: .It Cm ClientAliveInterval
144: Sets a timeout interval in seconds after which if no data has been received
145: from the client,
146: .Nm sshd
147: will send a message through the encrypted
148: channel to request a response from the client.
149: The default
150: is 0, indicating that these messages will not be sent to the client.
151: This option applies to protocol version 2 only.
152: .It Cm ClientAliveCountMax
153: Sets the number of client alive messages (see above) which may be
154: sent without
155: .Nm sshd
156: receiving any messages back from the client. If this threshold is
157: reached while client alive messages are being sent,
158: .Nm sshd
159: will disconnect the client, terminating the session. It is important
160: to note that the use of client alive messages is very different from
161: .Cm KeepAlive
162: (below). The client alive messages are sent through the
163: encrypted channel and therefore will not be spoofable. The TCP keepalive
164: option enabled by
165: .Cm KeepAlive
166: is spoofable. The client alive mechanism is valuable when the client or
167: server depend on knowing when a connection has become inactive.
168: .Pp
169: The default value is 3. If
170: .Cm ClientAliveInterval
171: (above) is set to 15, and
172: .Cm ClientAliveCountMax
173: is left at the default, unresponsive ssh clients
174: will be disconnected after approximately 45 seconds.
1.3 markus 175: .It Cm Compression
176: Specifies whether compression is allowed.
177: The argument must be
178: .Dq yes
179: or
180: .Dq no .
181: The default is
182: .Dq yes .
1.1 stevesk 183: .It Cm DenyGroups
184: This keyword can be followed by a list of group name patterns, separated
185: by spaces.
186: Login is disallowed for users whose primary group or supplementary
187: group list matches one of the patterns.
188: .Ql \&*
189: and
190: .Ql ?
191: can be used as
192: wildcards in the patterns.
193: Only group names are valid; a numerical group ID is not recognized.
194: By default, login is allowed for all groups.
195: .Pp
196: .It Cm DenyUsers
197: This keyword can be followed by a list of user name patterns, separated
198: by spaces.
199: Login is disallowed for user names that match one of the patterns.
200: .Ql \&*
201: and
202: .Ql ?
203: can be used as wildcards in the patterns.
204: Only user names are valid; a numerical user ID is not recognized.
205: By default, login is allowed for all users.
206: If the pattern takes the form USER@HOST then USER and HOST
207: are separately checked, restricting logins to particular
208: users from particular hosts.
209: .It Cm GatewayPorts
210: Specifies whether remote hosts are allowed to connect to ports
211: forwarded for the client.
212: By default,
213: .Nm sshd
1.15 ! jmc 214: binds remote port forwardings to the loopback address.
! 215: This prevents other remote hosts from connecting to forwarded ports.
1.1 stevesk 216: .Cm GatewayPorts
217: can be used to specify that
218: .Nm sshd
219: should bind remote port forwardings to the wildcard address,
220: thus allowing remote hosts to connect to forwarded ports.
221: The argument must be
222: .Dq yes
223: or
224: .Dq no .
225: The default is
226: .Dq no .
227: .It Cm HostbasedAuthentication
228: Specifies whether rhosts or /etc/hosts.equiv authentication together
229: with successful public key client host authentication is allowed
230: (hostbased authentication).
231: This option is similar to
232: .Cm RhostsRSAAuthentication
233: and applies to protocol version 2 only.
234: The default is
235: .Dq no .
236: .It Cm HostKey
237: Specifies a file containing a private host key
238: used by SSH.
239: The default is
240: .Pa /etc/ssh/ssh_host_key
241: for protocol version 1, and
242: .Pa /etc/ssh/ssh_host_rsa_key
243: and
244: .Pa /etc/ssh/ssh_host_dsa_key
245: for protocol version 2.
246: Note that
247: .Nm sshd
248: will refuse to use a file if it is group/world-accessible.
249: It is possible to have multiple host key files.
250: .Dq rsa1
251: keys are used for version 1 and
252: .Dq dsa
253: or
254: .Dq rsa
255: are used for version 2 of the SSH protocol.
256: .It Cm IgnoreRhosts
257: Specifies that
258: .Pa .rhosts
259: and
260: .Pa .shosts
261: files will not be used in
262: .Cm RhostsAuthentication ,
263: .Cm RhostsRSAAuthentication
264: or
265: .Cm HostbasedAuthentication .
266: .Pp
267: .Pa /etc/hosts.equiv
268: and
269: .Pa /etc/shosts.equiv
270: are still used.
271: The default is
272: .Dq yes .
273: .It Cm IgnoreUserKnownHosts
274: Specifies whether
275: .Nm sshd
276: should ignore the user's
277: .Pa $HOME/.ssh/known_hosts
278: during
279: .Cm RhostsRSAAuthentication
280: or
281: .Cm HostbasedAuthentication .
282: The default is
283: .Dq no .
284: .It Cm KeepAlive
285: Specifies whether the system should send TCP keepalive messages to the
286: other side.
287: If they are sent, death of the connection or crash of one
288: of the machines will be properly noticed.
289: However, this means that
290: connections will die if the route is down temporarily, and some people
291: find it annoying.
292: On the other hand, if keepalives are not sent,
293: sessions may hang indefinitely on the server, leaving
294: .Dq ghost
295: users and consuming server resources.
296: .Pp
297: The default is
298: .Dq yes
299: (to send keepalives), and the server will notice
300: if the network goes down or the client host crashes.
301: This avoids infinitely hanging sessions.
302: .Pp
303: To disable keepalives, the value should be set to
304: .Dq no .
305: .It Cm KerberosAuthentication
306: Specifies whether Kerberos authentication is allowed.
307: This can be in the form of a Kerberos ticket, or if
308: .Cm PasswordAuthentication
309: is yes, the password provided by the user will be validated through
310: the Kerberos KDC.
311: To use this option, the server needs a
312: Kerberos servtab which allows the verification of the KDC's identity.
313: Default is
314: .Dq no .
315: .It Cm KerberosOrLocalPasswd
316: If set then if password authentication through Kerberos fails then
317: the password will be validated via any additional local mechanism
318: such as
319: .Pa /etc/passwd .
320: Default is
321: .Dq yes .
322: .It Cm KerberosTgtPassing
323: Specifies whether a Kerberos TGT may be forwarded to the server.
324: Default is
325: .Dq no ,
326: as this only works when the Kerberos KDC is actually an AFS kaserver.
327: .It Cm KerberosTicketCleanup
328: Specifies whether to automatically destroy the user's ticket cache
329: file on logout.
330: Default is
331: .Dq yes .
332: .It Cm KeyRegenerationInterval
333: In protocol version 1, the ephemeral server key is automatically regenerated
334: after this many seconds (if it has been used).
335: The purpose of regeneration is to prevent
336: decrypting captured sessions by later breaking into the machine and
337: stealing the keys.
338: The key is never stored anywhere.
339: If the value is 0, the key is never regenerated.
340: The default is 3600 (seconds).
341: .It Cm ListenAddress
342: Specifies the local addresses
343: .Nm sshd
344: should listen on.
345: The following forms may be used:
346: .Pp
347: .Bl -item -offset indent -compact
348: .It
349: .Cm ListenAddress
350: .Sm off
351: .Ar host No | Ar IPv4_addr No | Ar IPv6_addr
352: .Sm on
353: .It
354: .Cm ListenAddress
355: .Sm off
356: .Ar host No | Ar IPv4_addr No : Ar port
357: .Sm on
358: .It
359: .Cm ListenAddress
360: .Sm off
361: .Oo
362: .Ar host No | Ar IPv6_addr Oc : Ar port
363: .Sm on
364: .El
365: .Pp
366: If
367: .Ar port
368: is not specified,
369: .Nm sshd
370: will listen on the address and all prior
371: .Cm Port
372: options specified. The default is to listen on all local
1.15 ! jmc 373: addresses.
! 374: Multiple
1.1 stevesk 375: .Cm ListenAddress
376: options are permitted. Additionally, any
377: .Cm Port
378: options must precede this option for non port qualified addresses.
379: .It Cm LoginGraceTime
380: The server disconnects after this time if the user has not
381: successfully logged in.
382: If the value is 0, there is no time limit.
1.12 stevesk 383: The default is 120 seconds.
1.1 stevesk 384: .It Cm LogLevel
385: Gives the verbosity level that is used when logging messages from
386: .Nm sshd .
387: The possible values are:
388: QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2 and DEBUG3.
1.15 ! jmc 389: The default is INFO.
! 390: DEBUG and DEBUG1 are equivalent.
! 391: DEBUG2 and DEBUG3 each specify higher levels of debugging output.
! 392: Logging with a DEBUG level violates the privacy of users and is not recommended.
1.1 stevesk 393: .It Cm MACs
394: Specifies the available MAC (message authentication code) algorithms.
395: The MAC algorithm is used in protocol version 2
396: for data integrity protection.
397: Multiple algorithms must be comma-separated.
398: The default is
399: .Dq hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 .
400: .It Cm MaxStartups
401: Specifies the maximum number of concurrent unauthenticated connections to the
402: .Nm sshd
403: daemon.
404: Additional connections will be dropped until authentication succeeds or the
405: .Cm LoginGraceTime
406: expires for a connection.
407: The default is 10.
408: .Pp
409: Alternatively, random early drop can be enabled by specifying
410: the three colon separated values
411: .Dq start:rate:full
412: (e.g., "10:30:60").
413: .Nm sshd
414: will refuse connection attempts with a probability of
415: .Dq rate/100
416: (30%)
417: if there are currently
418: .Dq start
419: (10)
420: unauthenticated connections.
421: The probability increases linearly and all connection attempts
422: are refused if the number of unauthenticated connections reaches
423: .Dq full
424: (60).
425: .It Cm PasswordAuthentication
426: Specifies whether password authentication is allowed.
427: The default is
428: .Dq yes .
429: .It Cm PermitEmptyPasswords
430: When password authentication is allowed, it specifies whether the
431: server allows login to accounts with empty password strings.
432: The default is
433: .Dq no .
434: .It Cm PermitRootLogin
435: Specifies whether root can login using
436: .Xr ssh 1 .
437: The argument must be
438: .Dq yes ,
439: .Dq without-password ,
440: .Dq forced-commands-only
441: or
442: .Dq no .
443: The default is
444: .Dq yes .
445: .Pp
446: If this option is set to
447: .Dq without-password
448: password authentication is disabled for root.
449: .Pp
450: If this option is set to
451: .Dq forced-commands-only
452: root login with public key authentication will be allowed,
453: but only if the
454: .Ar command
455: option has been specified
456: (which may be useful for taking remote backups even if root login is
457: normally not allowed). All other authentication methods are disabled
458: for root.
459: .Pp
460: If this option is set to
461: .Dq no
462: root is not allowed to login.
1.6 markus 463: .It Cm PermitUserEnvironment
464: Specifies whether
465: .Pa ~/.ssh/environment
1.9 stevesk 466: and
1.6 markus 467: .Cm environment=
468: options in
469: .Pa ~/.ssh/authorized_keys
1.9 stevesk 470: are processed by
471: .Nm sshd .
1.6 markus 472: The default is
473: .Dq no .
1.9 stevesk 474: Enabling environment processing may enable users to bypass access
475: restrictions in some configurations using mechanisms such as
476: .Ev LD_PRELOAD .
1.1 stevesk 477: .It Cm PidFile
1.4 stevesk 478: Specifies the file that contains the process ID of the
1.1 stevesk 479: .Nm sshd
480: daemon.
481: The default is
482: .Pa /var/run/sshd.pid .
483: .It Cm Port
484: Specifies the port number that
485: .Nm sshd
486: listens on.
487: The default is 22.
488: Multiple options of this type are permitted.
489: See also
490: .Cm ListenAddress .
491: .It Cm PrintLastLog
492: Specifies whether
493: .Nm sshd
494: should print the date and time when the user last logged in.
495: The default is
496: .Dq yes .
497: .It Cm PrintMotd
498: Specifies whether
499: .Nm sshd
500: should print
501: .Pa /etc/motd
502: when a user logs in interactively.
503: (On some systems it is also printed by the shell,
504: .Pa /etc/profile ,
505: or equivalent.)
506: The default is
507: .Dq yes .
508: .It Cm Protocol
509: Specifies the protocol versions
510: .Nm sshd
1.5 stevesk 511: supports.
1.1 stevesk 512: The possible values are
513: .Dq 1
514: and
515: .Dq 2 .
516: Multiple versions must be comma-separated.
517: The default is
518: .Dq 2,1 .
1.5 stevesk 519: Note that the order of the protocol list does not indicate preference,
520: because the client selects among multiple protocol versions offered
521: by the server.
522: Specifying
523: .Dq 2,1
524: is identical to
525: .Dq 1,2 .
1.1 stevesk 526: .It Cm PubkeyAuthentication
527: Specifies whether public key authentication is allowed.
528: The default is
529: .Dq yes .
530: Note that this option applies to protocol version 2 only.
531: .It Cm RhostsAuthentication
532: Specifies whether authentication using rhosts or /etc/hosts.equiv
533: files is sufficient.
534: Normally, this method should not be permitted because it is insecure.
535: .Cm RhostsRSAAuthentication
536: should be used
537: instead, because it performs RSA-based host authentication in addition
538: to normal rhosts or /etc/hosts.equiv authentication.
539: The default is
540: .Dq no .
541: This option applies to protocol version 1 only.
542: .It Cm RhostsRSAAuthentication
543: Specifies whether rhosts or /etc/hosts.equiv authentication together
544: with successful RSA host authentication is allowed.
545: The default is
546: .Dq no .
547: This option applies to protocol version 1 only.
548: .It Cm RSAAuthentication
549: Specifies whether pure RSA authentication is allowed.
550: The default is
551: .Dq yes .
552: This option applies to protocol version 1 only.
553: .It Cm ServerKeyBits
554: Defines the number of bits in the ephemeral protocol version 1 server key.
555: The minimum value is 512, and the default is 768.
556: .It Cm StrictModes
557: Specifies whether
558: .Nm sshd
559: should check file modes and ownership of the
560: user's files and home directory before accepting login.
561: This is normally desirable because novices sometimes accidentally leave their
562: directory or files world-writable.
563: The default is
564: .Dq yes .
565: .It Cm Subsystem
566: Configures an external subsystem (e.g., file transfer daemon).
567: Arguments should be a subsystem name and a command to execute upon subsystem
568: request.
569: The command
570: .Xr sftp-server 8
571: implements the
572: .Dq sftp
573: file transfer subsystem.
574: By default no subsystems are defined.
575: Note that this option applies to protocol version 2 only.
576: .It Cm SyslogFacility
577: Gives the facility code that is used when logging messages from
578: .Nm sshd .
579: The possible values are: DAEMON, USER, AUTH, LOCAL0, LOCAL1, LOCAL2,
580: LOCAL3, LOCAL4, LOCAL5, LOCAL6, LOCAL7.
581: The default is AUTH.
582: .It Cm UseLogin
583: Specifies whether
584: .Xr login 1
585: is used for interactive login sessions.
586: The default is
587: .Dq no .
588: Note that
589: .Xr login 1
590: is never used for remote command execution.
591: Note also, that if this is enabled,
592: .Cm X11Forwarding
593: will be disabled because
594: .Xr login 1
595: does not know how to handle
596: .Xr xauth 1
1.15 ! jmc 597: cookies.
! 598: If
1.1 stevesk 599: .Cm UsePrivilegeSeparation
600: is specified, it will be disabled after authentication.
601: .It Cm UsePrivilegeSeparation
602: Specifies whether
603: .Nm sshd
1.2 stevesk 604: separates privileges by creating an unprivileged child process
1.15 ! jmc 605: to deal with incoming network traffic.
! 606: After successful authentication, another process will be created that has
! 607: the privilege of the authenticated user.
! 608: The goal of privilege separation is to prevent privilege
1.1 stevesk 609: escalation by containing any corruption within the unprivileged processes.
610: The default is
611: .Dq yes .
612: .It Cm VerifyReverseMapping
613: Specifies whether
614: .Nm sshd
615: should try to verify the remote host name and check that
616: the resolved host name for the remote IP address maps back to the
617: very same IP address.
618: The default is
619: .Dq no .
620: .It Cm X11DisplayOffset
621: Specifies the first display number available for
622: .Nm sshd Ns 's
623: X11 forwarding.
624: This prevents
625: .Nm sshd
626: from interfering with real X11 servers.
627: The default is 10.
628: .It Cm X11Forwarding
629: Specifies whether X11 forwarding is permitted.
1.13 stevesk 630: The argument must be
631: .Dq yes
632: or
633: .Dq no .
1.1 stevesk 634: The default is
635: .Dq no .
1.13 stevesk 636: .Pp
637: When X11 forwarding is enabled, there may be additional exposure to
638: the server and to client displays if the
639: .Nm sshd
640: proxy display is configured to listen on the wildcard address (see
641: .Cm X11UseLocalhost
642: below), however this is not the default.
643: Additionally, the authentication spoofing and authentication data
644: verification and substitution occur on the client side.
645: The security risk of using X11 forwarding is that the client's X11
646: display server may be exposed to attack when the ssh client requests
647: forwarding (see the warnings for
648: .Cm ForwardX11
649: in
650: .Xr ssh_config 5 ).
651: A system administrator may have a stance in which they want to
652: protect clients that may expose themselves to attack by unwittingly
653: requesting X11 forwarding, which can warrant a
654: .Dq no
655: setting.
656: .Pp
657: Note that disabling X11 forwarding does not prevent users from
658: forwarding X11 traffic, as users can always install their own forwarders.
1.1 stevesk 659: X11 forwarding is automatically disabled if
660: .Cm UseLogin
661: is enabled.
662: .It Cm X11UseLocalhost
663: Specifies whether
664: .Nm sshd
665: should bind the X11 forwarding server to the loopback address or to
1.15 ! jmc 666: the wildcard address.
! 667: By default,
1.1 stevesk 668: .Nm sshd
669: binds the forwarding server to the loopback address and sets the
670: hostname part of the
671: .Ev DISPLAY
672: environment variable to
673: .Dq localhost .
1.8 stevesk 674: This prevents remote hosts from connecting to the proxy display.
1.1 stevesk 675: However, some older X11 clients may not function with this
676: configuration.
677: .Cm X11UseLocalhost
678: may be set to
679: .Dq no
680: to specify that the forwarding server should be bound to the wildcard
681: address.
682: The argument must be
683: .Dq yes
684: or
685: .Dq no .
686: The default is
687: .Dq yes .
688: .It Cm XAuthLocation
1.11 stevesk 689: Specifies the full pathname of the
1.1 stevesk 690: .Xr xauth 1
691: program.
692: The default is
693: .Pa /usr/X11R6/bin/xauth .
694: .El
695: .Ss Time Formats
696: .Pp
697: .Nm sshd
698: command-line arguments and configuration file options that specify time
699: may be expressed using a sequence of the form:
700: .Sm off
1.7 stevesk 701: .Ar time Op Ar qualifier ,
1.1 stevesk 702: .Sm on
703: where
704: .Ar time
705: is a positive integer value and
706: .Ar qualifier
707: is one of the following:
708: .Pp
709: .Bl -tag -width Ds -compact -offset indent
710: .It Cm <none>
711: seconds
712: .It Cm s | Cm S
713: seconds
714: .It Cm m | Cm M
715: minutes
716: .It Cm h | Cm H
717: hours
718: .It Cm d | Cm D
719: days
720: .It Cm w | Cm W
721: weeks
722: .El
723: .Pp
724: Each member of the sequence is added together to calculate
725: the total time value.
726: .Pp
727: Time format examples:
728: .Pp
729: .Bl -tag -width Ds -compact -offset indent
730: .It 600
731: 600 seconds (10 minutes)
732: .It 10m
733: 10 minutes
734: .It 1h30m
735: 1 hour 30 minutes (90 minutes)
736: .El
737: .Sh FILES
738: .Bl -tag -width Ds
739: .It Pa /etc/ssh/sshd_config
740: Contains configuration data for
741: .Nm sshd .
742: This file should be writable by root only, but it is recommended
743: (though not necessary) that it be world-readable.
744: .El
745: .Sh AUTHORS
746: OpenSSH is a derivative of the original and free
747: ssh 1.2.12 release by Tatu Ylonen.
748: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
749: Theo de Raadt and Dug Song
750: removed many bugs, re-added newer features and
751: created OpenSSH.
752: Markus Friedl contributed the support for SSH
753: protocol versions 1.5 and 2.0.
754: Niels Provos and Markus Friedl contributed support
755: for privilege separation.
756: .Sh SEE ALSO
757: .Xr sshd 8
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