Annotation of src/usr.bin/ssh/ssh_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.
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: .\"
1.24 ! jakob 37: .\" $OpenBSD: ssh_config.5,v 1.23 2003/10/12 13:12:13 jmc Exp $
1.1 stevesk 38: .Dd September 25, 1999
39: .Dt SSH_CONFIG 5
40: .Os
41: .Sh NAME
42: .Nm ssh_config
43: .Nd OpenSSH SSH client configuration files
44: .Sh SYNOPSIS
45: .Bl -tag -width Ds -compact
46: .It Pa $HOME/.ssh/config
47: .It Pa /etc/ssh/ssh_config
48: .El
49: .Sh DESCRIPTION
50: .Nm ssh
51: obtains configuration data from the following sources in
52: the following order:
1.2 stevesk 53: .Bl -enum -offset indent -compact
54: .It
55: command-line options
56: .It
57: user's configuration file
58: .Pq Pa $HOME/.ssh/config
59: .It
60: system-wide configuration file
61: .Pq Pa /etc/ssh/ssh_config
62: .El
1.1 stevesk 63: .Pp
64: For each parameter, the first obtained value
65: will be used.
66: The configuration files contain sections bracketed by
67: .Dq Host
68: specifications, and that section is only applied for hosts that
69: match one of the patterns given in the specification.
70: The matched host name is the one given on the command line.
71: .Pp
72: Since the first obtained value for each parameter is used, more
73: host-specific declarations should be given near the beginning of the
74: file, and general defaults at the end.
75: .Pp
76: The configuration file has the following format:
77: .Pp
78: Empty lines and lines starting with
79: .Ql #
80: are comments.
81: .Pp
82: Otherwise a line is of the format
83: .Dq keyword arguments .
84: Configuration options may be separated by whitespace or
85: optional whitespace and exactly one
86: .Ql = ;
87: the latter format is useful to avoid the need to quote whitespace
88: when specifying configuration options using the
89: .Nm ssh ,
90: .Nm scp
91: and
92: .Nm sftp
93: .Fl o
94: option.
95: .Pp
96: The possible
97: keywords and their meanings are as follows (note that
98: keywords are case-insensitive and arguments are case-sensitive):
99: .Bl -tag -width Ds
100: .It Cm Host
101: Restricts the following declarations (up to the next
102: .Cm Host
103: keyword) to be only for those hosts that match one of the patterns
104: given after the keyword.
105: .Ql \&*
106: and
1.20 jmc 107: .Ql \&?
1.1 stevesk 108: can be used as wildcards in the
109: patterns.
110: A single
111: .Ql \&*
112: as a pattern can be used to provide global
113: defaults for all hosts.
114: The host is the
115: .Ar hostname
116: argument given on the command line (i.e., the name is not converted to
117: a canonicalized host name before matching).
1.10 djm 118: .It Cm AddressFamily
1.11 jmc 119: Specifies which address family to use when connecting.
120: Valid arguments are
1.10 djm 121: .Dq any ,
122: .Dq inet
123: (Use IPv4 only) or
124: .Dq inet6
125: (Use IPv6 only.)
1.1 stevesk 126: .It Cm BatchMode
127: If set to
128: .Dq yes ,
129: passphrase/password querying will be disabled.
130: This option is useful in scripts and other batch jobs where no user
131: is present to supply the password.
132: The argument must be
133: .Dq yes
134: or
135: .Dq no .
136: The default is
137: .Dq no .
138: .It Cm BindAddress
139: Specify the interface to transmit from on machines with multiple
140: interfaces or aliased addresses.
141: Note that this option does not work if
142: .Cm UsePrivilegedPort
143: is set to
144: .Dq yes .
145: .It Cm ChallengeResponseAuthentication
146: Specifies whether to use challenge response authentication.
147: The argument to this keyword must be
148: .Dq yes
149: or
150: .Dq no .
151: The default is
152: .Dq yes .
153: .It Cm CheckHostIP
154: If this flag is set to
155: .Dq yes ,
156: ssh will additionally check the host IP address in the
157: .Pa known_hosts
158: file.
159: This allows ssh to detect if a host key changed due to DNS spoofing.
160: If the option is set to
161: .Dq no ,
162: the check will not be executed.
163: The default is
164: .Dq yes .
165: .It Cm Cipher
166: Specifies the cipher to use for encrypting the session
167: in protocol version 1.
168: Currently,
169: .Dq blowfish ,
170: .Dq 3des ,
171: and
172: .Dq des
173: are supported.
174: .Ar des
175: is only supported in the
176: .Nm ssh
177: client for interoperability with legacy protocol 1 implementations
178: that do not support the
179: .Ar 3des
1.7 jmc 180: cipher.
181: Its use is strongly discouraged due to cryptographic weaknesses.
1.1 stevesk 182: The default is
183: .Dq 3des .
184: .It Cm Ciphers
185: Specifies the ciphers allowed for protocol version 2
186: in order of preference.
187: Multiple ciphers must be comma-separated.
188: The default is
189: .Bd -literal
190: ``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,
191: aes192-cbc,aes256-cbc''
192: .Ed
193: .It Cm ClearAllForwardings
194: Specifies that all local, remote and dynamic port forwardings
195: specified in the configuration files or on the command line be
1.7 jmc 196: cleared.
197: This option is primarily useful when used from the
1.1 stevesk 198: .Nm ssh
199: command line to clear port forwardings set in
200: configuration files, and is automatically set by
201: .Xr scp 1
202: and
203: .Xr sftp 1 .
204: The argument must be
205: .Dq yes
206: or
207: .Dq no .
208: The default is
209: .Dq no .
210: .It Cm Compression
211: Specifies whether to use compression.
212: The argument must be
213: .Dq yes
214: or
215: .Dq no .
216: The default is
217: .Dq no .
218: .It Cm CompressionLevel
219: Specifies the compression level to use if compression is enabled.
220: The argument must be an integer from 1 (fast) to 9 (slow, best).
221: The default level is 6, which is good for most applications.
222: The meaning of the values is the same as in
223: .Xr gzip 1 .
224: Note that this option applies to protocol version 1 only.
225: .It Cm ConnectionAttempts
226: Specifies the number of tries (one per second) to make before exiting.
227: The argument must be an integer.
228: This may be useful in scripts if the connection sometimes fails.
229: The default is 1.
1.9 djm 230: .It Cm ConnectTimeout
231: Specifies the timeout (in seconds) used when connecting to the ssh
1.11 jmc 232: server, instead of using the default system TCP timeout.
233: This value is used only when the target is down or really unreachable,
234: not when it refuses the connection.
1.1 stevesk 235: .It Cm DynamicForward
236: Specifies that a TCP/IP port on the local machine be forwarded
237: over the secure channel, and the application
238: protocol is then used to determine where to connect to from the
1.7 jmc 239: remote machine.
240: The argument must be a port number.
1.15 markus 241: Currently the SOCKS4 and SOCKS5 protocols are supported, and
1.1 stevesk 242: .Nm ssh
1.15 markus 243: will act as a SOCKS server.
1.1 stevesk 244: Multiple forwardings may be specified, and
1.7 jmc 245: additional forwardings can be given on the command line.
246: Only the superuser can forward privileged ports.
1.14 markus 247: .It Cm EnableSSHKeysign
248: Setting this option to
249: .Dq yes
250: in the global client configuration file
251: .Pa /etc/ssh/ssh_config
252: enables the use of the helper program
253: .Xr ssh-keysign 8
254: during
255: .Cm HostbasedAuthentication .
256: The argument must be
257: .Dq yes
258: or
259: .Dq no .
260: The default is
261: .Dq no .
1.23 jmc 262: This option should be placed in the non-hostspecific section.
1.14 markus 263: See
264: .Xr ssh-keysign 8
265: for more information.
1.1 stevesk 266: .It Cm EscapeChar
267: Sets the escape character (default:
268: .Ql ~ ) .
269: The escape character can also
270: be set on the command line.
271: The argument should be a single character,
272: .Ql ^
273: followed by a letter, or
274: .Dq none
275: to disable the escape
276: character entirely (making the connection transparent for binary
277: data).
278: .It Cm ForwardAgent
279: Specifies whether the connection to the authentication agent (if any)
280: will be forwarded to the remote machine.
281: The argument must be
282: .Dq yes
283: or
284: .Dq no .
285: The default is
286: .Dq no .
1.3 stevesk 287: .Pp
1.7 jmc 288: Agent forwarding should be enabled with caution.
289: Users with the ability to bypass file permissions on the remote host
290: (for the agent's Unix-domain socket)
291: can access the local agent through the forwarded connection.
292: An attacker cannot obtain key material from the agent,
1.3 stevesk 293: however they can perform operations on the keys that enable them to
294: authenticate using the identities loaded into the agent.
1.1 stevesk 295: .It Cm ForwardX11
296: Specifies whether X11 connections will be automatically redirected
297: over the secure channel and
298: .Ev DISPLAY
299: set.
300: The argument must be
301: .Dq yes
302: or
303: .Dq no .
304: The default is
305: .Dq no .
1.3 stevesk 306: .Pp
1.7 jmc 307: X11 forwarding should be enabled with caution.
308: Users with the ability to bypass file permissions on the remote host
1.22 markus 309: (for the user's X11 authorization database)
1.7 jmc 310: can access the local X11 display through the forwarded connection.
1.22 markus 311: An attacker may then be able to perform activities such as keystroke monitoring
312: if the
313: .Cm ForwardX11Trusted
314: option is also enabled.
315: .It Cm ForwardX11Trusted
316: If the this option is set to
317: .Dq yes
318: then remote X11 clients will have full access to the original X11 display.
319: If this option is set to
320: .Dq no
321: then remote X11 clients will be considered untrusted and prevented
322: from stealing or tampering with data belonging to trusted X11
323: clients.
324: .Pp
325: The default is
326: .Dq no .
327: .Pp
328: See the X11 SECURITY extension specification for full details on
329: the restrictions imposed on untrusted clients.
1.1 stevesk 330: .It Cm GatewayPorts
331: Specifies whether remote hosts are allowed to connect to local
332: forwarded ports.
333: By default,
334: .Nm ssh
1.7 jmc 335: binds local port forwardings to the loopback address.
336: This prevents other remote hosts from connecting to forwarded ports.
1.1 stevesk 337: .Cm GatewayPorts
338: can be used to specify that
339: .Nm ssh
340: should bind local port forwardings to the wildcard address,
341: thus allowing remote hosts to connect to forwarded ports.
342: The argument must be
343: .Dq yes
344: or
345: .Dq no .
346: The default is
347: .Dq no .
348: .It Cm GlobalKnownHostsFile
349: Specifies a file to use for the global
350: host key database instead of
351: .Pa /etc/ssh/ssh_known_hosts .
1.18 markus 352: .It Cm GSSAPIAuthentication
353: Specifies whether authentication based on GSSAPI may be used, either using
354: the result of a successful key exchange, or using GSSAPI user
355: authentication.
1.20 jmc 356: The default is
1.21 markus 357: .Dq no .
1.18 markus 358: Note that this option applies to protocol version 2 only.
359: .It Cm GSSAPIDelegateCredentials
360: Forward (delegate) credentials to the server.
361: The default is
362: .Dq no .
363: Note that this option applies to protocol version 2 only.
1.1 stevesk 364: .It Cm HostbasedAuthentication
365: Specifies whether to try rhosts based authentication with public key
366: authentication.
367: The argument must be
368: .Dq yes
369: or
370: .Dq no .
371: The default is
372: .Dq no .
373: This option applies to protocol version 2 only and
374: is similar to
375: .Cm RhostsRSAAuthentication .
376: .It Cm HostKeyAlgorithms
377: Specifies the protocol version 2 host key algorithms
378: that the client wants to use in order of preference.
379: The default for this option is:
380: .Dq ssh-rsa,ssh-dss .
381: .It Cm HostKeyAlias
382: Specifies an alias that should be used instead of the
383: real host name when looking up or saving the host key
384: in the host key database files.
385: This option is useful for tunneling ssh connections
386: or for multiple servers running on a single host.
387: .It Cm HostName
388: Specifies the real host name to log into.
389: This can be used to specify nicknames or abbreviations for hosts.
390: Default is the name given on the command line.
391: Numeric IP addresses are also permitted (both on the command line and in
392: .Cm HostName
393: specifications).
394: .It Cm IdentityFile
395: Specifies a file from which the user's RSA or DSA authentication identity
1.11 jmc 396: is read.
397: The default is
1.1 stevesk 398: .Pa $HOME/.ssh/identity
399: for protocol version 1, and
400: .Pa $HOME/.ssh/id_rsa
401: and
402: .Pa $HOME/.ssh/id_dsa
403: for protocol version 2.
404: Additionally, any identities represented by the authentication agent
405: will be used for authentication.
406: The file name may use the tilde
407: syntax to refer to a user's home directory.
408: It is possible to have
409: multiple identity files specified in configuration files; all these
410: identities will be tried in sequence.
411: .It Cm KeepAlive
412: Specifies whether the system should send TCP keepalive messages to the
413: other side.
414: If they are sent, death of the connection or crash of one
415: of the machines will be properly noticed.
416: However, this means that
417: connections will die if the route is down temporarily, and some people
418: find it annoying.
419: .Pp
420: The default is
421: .Dq yes
422: (to send keepalives), and the client will notice
423: if the network goes down or the remote host dies.
424: This is important in scripts, and many users want it too.
425: .Pp
426: To disable keepalives, the value should be set to
427: .Dq no .
428: .It Cm LocalForward
429: Specifies that a TCP/IP port on the local machine be forwarded over
430: the secure channel to the specified host and port from the remote machine.
431: The first argument must be a port number, and the second must be
432: .Ar host:port .
433: IPv6 addresses can be specified with an alternative syntax:
434: .Ar host/port .
435: Multiple forwardings may be specified, and additional
436: forwardings can be given on the command line.
437: Only the superuser can forward privileged ports.
438: .It Cm LogLevel
439: Gives the verbosity level that is used when logging messages from
440: .Nm ssh .
441: The possible values are:
442: QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2 and DEBUG3.
1.7 jmc 443: The default is INFO.
444: DEBUG and DEBUG1 are equivalent.
445: DEBUG2 and DEBUG3 each specify higher levels of verbose output.
1.1 stevesk 446: .It Cm MACs
447: Specifies the MAC (message authentication code) algorithms
448: in order of preference.
449: The MAC algorithm is used in protocol version 2
450: for data integrity protection.
451: Multiple algorithms must be comma-separated.
452: The default is
453: .Dq hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 .
454: .It Cm NoHostAuthenticationForLocalhost
455: This option can be used if the home directory is shared across machines.
456: In this case localhost will refer to a different machine on each of
457: the machines and the user will get many warnings about changed host keys.
458: However, this option disables host authentication for localhost.
459: The argument to this keyword must be
460: .Dq yes
461: or
462: .Dq no .
463: The default is to check the host key for localhost.
464: .It Cm NumberOfPasswordPrompts
465: Specifies the number of password prompts before giving up.
466: The argument to this keyword must be an integer.
467: Default is 3.
468: .It Cm PasswordAuthentication
469: Specifies whether to use password authentication.
470: The argument to this keyword must be
471: .Dq yes
472: or
473: .Dq no .
474: The default is
475: .Dq yes .
476: .It Cm Port
477: Specifies the port number to connect on the remote host.
478: Default is 22.
479: .It Cm PreferredAuthentications
480: Specifies the order in which the client should try protocol 2
1.11 jmc 481: authentication methods.
482: This allows a client to prefer one method (e.g.
1.1 stevesk 483: .Cm keyboard-interactive )
484: over another method (e.g.
485: .Cm password )
486: The default for this option is:
487: .Dq hostbased,publickey,keyboard-interactive,password .
488: .It Cm Protocol
489: Specifies the protocol versions
490: .Nm ssh
491: should support in order of preference.
492: The possible values are
493: .Dq 1
494: and
495: .Dq 2 .
496: Multiple versions must be comma-separated.
497: The default is
498: .Dq 2,1 .
499: This means that
500: .Nm ssh
501: tries version 2 and falls back to version 1
502: if version 2 is not available.
503: .It Cm ProxyCommand
504: Specifies the command to use to connect to the server.
505: The command
506: string extends to the end of the line, and is executed with
507: .Pa /bin/sh .
508: In the command string,
509: .Ql %h
510: will be substituted by the host name to
511: connect and
512: .Ql %p
513: by the port.
514: The command can be basically anything,
515: and should read from its standard input and write to its standard output.
516: It should eventually connect an
517: .Xr sshd 8
518: server running on some machine, or execute
519: .Ic sshd -i
520: somewhere.
521: Host key management will be done using the
522: HostName of the host being connected (defaulting to the name typed by
523: the user).
1.7 jmc 524: Setting the command to
525: .Dq none
1.6 markus 526: disables this option entirely.
1.1 stevesk 527: Note that
528: .Cm CheckHostIP
529: is not available for connects with a proxy command.
530: .Pp
531: .It Cm PubkeyAuthentication
532: Specifies whether to try public key authentication.
533: The argument to this keyword must be
534: .Dq yes
535: or
536: .Dq no .
537: The default is
538: .Dq yes .
539: This option applies to protocol version 2 only.
540: .It Cm RemoteForward
541: Specifies that a TCP/IP port on the remote machine be forwarded over
542: the secure channel to the specified host and port from the local machine.
543: The first argument must be a port number, and the second must be
544: .Ar host:port .
545: IPv6 addresses can be specified with an alternative syntax:
546: .Ar host/port .
547: Multiple forwardings may be specified, and additional
548: forwardings can be given on the command line.
549: Only the superuser can forward privileged ports.
550: .It Cm RhostsRSAAuthentication
551: Specifies whether to try rhosts based authentication with RSA host
552: authentication.
553: The argument must be
554: .Dq yes
555: or
556: .Dq no .
557: The default is
558: .Dq no .
559: This option applies to protocol version 1 only and requires
560: .Nm ssh
561: to be setuid root.
562: .It Cm RSAAuthentication
563: Specifies whether to try RSA authentication.
564: The argument to this keyword must be
565: .Dq yes
566: or
567: .Dq no .
568: RSA authentication will only be
569: attempted if the identity file exists, or an authentication agent is
570: running.
571: The default is
572: .Dq yes .
573: Note that this option applies to protocol version 1 only.
574: .It Cm SmartcardDevice
1.11 jmc 575: Specifies which smartcard device to use.
576: The argument to this keyword is the device
1.1 stevesk 577: .Nm ssh
578: should use to communicate with a smartcard used for storing the user's
1.11 jmc 579: private RSA key.
580: By default, no device is specified and smartcard support is not activated.
1.1 stevesk 581: .It Cm StrictHostKeyChecking
582: If this flag is set to
583: .Dq yes ,
584: .Nm ssh
585: will never automatically add host keys to the
586: .Pa $HOME/.ssh/known_hosts
587: file, and refuses to connect to hosts whose host key has changed.
588: This provides maximum protection against trojan horse attacks,
589: however, can be annoying when the
590: .Pa /etc/ssh/ssh_known_hosts
591: file is poorly maintained, or connections to new hosts are
592: frequently made.
593: This option forces the user to manually
594: add all new hosts.
595: If this flag is set to
596: .Dq no ,
597: .Nm ssh
598: will automatically add new host keys to the
599: user known hosts files.
600: If this flag is set to
601: .Dq ask ,
602: new host keys
603: will be added to the user known host files only after the user
604: has confirmed that is what they really want to do, and
605: .Nm ssh
606: will refuse to connect to hosts whose host key has changed.
607: The host keys of
608: known hosts will be verified automatically in all cases.
609: The argument must be
610: .Dq yes ,
611: .Dq no
612: or
613: .Dq ask .
614: The default is
615: .Dq ask .
616: .It Cm UsePrivilegedPort
617: Specifies whether to use a privileged port for outgoing connections.
618: The argument must be
619: .Dq yes
620: or
621: .Dq no .
622: The default is
623: .Dq no .
1.4 stevesk 624: If set to
625: .Dq yes
626: .Nm ssh
627: must be setuid root.
1.1 stevesk 628: Note that this option must be set to
629: .Dq yes
1.17 markus 630: for
1.1 stevesk 631: .Cm RhostsRSAAuthentication
1.17 markus 632: with older servers.
1.1 stevesk 633: .It Cm User
634: Specifies the user to log in as.
635: This can be useful when a different user name is used on different machines.
636: This saves the trouble of
637: having to remember to give the user name on the command line.
638: .It Cm UserKnownHostsFile
639: Specifies a file to use for the user
640: host key database instead of
641: .Pa $HOME/.ssh/known_hosts .
1.8 jakob 642: .It Cm VerifyHostKeyDNS
643: Specifies whether to verify the remote key using DNS and SSHFP resource
644: records.
1.24 ! jakob 645: If this option is set to
! 646: .Dq yes ,
! 647: the client will implicitly trust keys that matches a secure fingerprint
! 648: from DNS.
! 649: Insecure fingerprints will be handled as if this option was set to
! 650: .Dq ask .
! 651: If this option is set to
! 652: .Dq ask ,
! 653: information on fingerprint match will be displayed, but the user will still
! 654: need to confirm new host keys according to the
! 655: .Cm StrictHostKeyChecking
! 656: option.
! 657: The argument must be
! 658: .Dq yes ,
! 659: .Dq no
! 660: or
! 661: .Dq ask .
1.8 jakob 662: The default is
663: .Dq no .
1.12 jakob 664: Note that this option applies to protocol version 2 only.
1.1 stevesk 665: .It Cm XAuthLocation
1.5 stevesk 666: Specifies the full pathname of the
1.1 stevesk 667: .Xr xauth 1
668: program.
669: The default is
670: .Pa /usr/X11R6/bin/xauth .
671: .El
672: .Sh FILES
673: .Bl -tag -width Ds
674: .It Pa $HOME/.ssh/config
675: This is the per-user configuration file.
676: The format of this file is described above.
677: This file is used by the
678: .Nm ssh
679: client.
680: This file does not usually contain any sensitive information,
681: but the recommended permissions are read/write for the user, and not
682: accessible by others.
683: .It Pa /etc/ssh/ssh_config
684: Systemwide configuration file.
685: This file provides defaults for those
686: values that are not specified in the user's configuration file, and
687: for those users who do not have a configuration file.
688: This file must be world-readable.
689: .El
1.13 jmc 690: .Sh SEE ALSO
691: .Xr ssh 1
1.1 stevesk 692: .Sh AUTHORS
693: OpenSSH is a derivative of the original and free
694: ssh 1.2.12 release by Tatu Ylonen.
695: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
696: Theo de Raadt and Dug Song
697: removed many bugs, re-added newer features and
698: created OpenSSH.
699: Markus Friedl contributed the support for SSH
700: protocol versions 1.5 and 2.0.