Annotation of src/usr.bin/ssh/ssh_config.5, Revision 1.151
1.1 stevesk 1: .\"
2: .\" Author: Tatu Ylonen <ylo@cs.hut.fi>
3: .\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: .\" All rights reserved
5: .\"
6: .\" As far as I am concerned, the code I have written for this software
7: .\" can be used freely for any purpose. Any derived versions of this
8: .\" software must be clearly marked as such, and if the derived work is
9: .\" incompatible with the protocol description in the RFC file, it must be
10: .\" called by a name other than "ssh" or "Secure Shell".
11: .\"
12: .\" Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
13: .\" Copyright (c) 1999 Aaron Campbell. All rights reserved.
14: .\" Copyright (c) 1999 Theo de Raadt. All rights reserved.
15: .\"
16: .\" Redistribution and use in source and binary forms, with or without
17: .\" modification, are permitted provided that the following conditions
18: .\" are met:
19: .\" 1. Redistributions of source code must retain the above copyright
20: .\" notice, this list of conditions and the following disclaimer.
21: .\" 2. Redistributions in binary form must reproduce the above copyright
22: .\" notice, this list of conditions and the following disclaimer in the
23: .\" documentation and/or other materials provided with the distribution.
24: .\"
25: .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
26: .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
27: .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
28: .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
29: .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
30: .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
31: .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
32: .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33: .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34: .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
35: .\"
1.151 ! djm 36: .\" $OpenBSD: ssh_config.5,v 1.150 2011/05/07 23:19:39 jmc Exp $
! 37: .Dd $Mdocdate: May 7 2011 $
1.1 stevesk 38: .Dt SSH_CONFIG 5
39: .Os
40: .Sh NAME
41: .Nm ssh_config
42: .Nd OpenSSH SSH client configuration files
43: .Sh SYNOPSIS
1.98 jmc 44: .Nm ~/.ssh/config
45: .Nm /etc/ssh/ssh_config
1.1 stevesk 46: .Sh DESCRIPTION
1.84 jmc 47: .Xr ssh 1
1.1 stevesk 48: obtains configuration data from the following sources in
49: the following order:
1.79 jmc 50: .Pp
1.2 stevesk 51: .Bl -enum -offset indent -compact
52: .It
53: command-line options
54: .It
55: user's configuration file
1.50 djm 56: .Pq Pa ~/.ssh/config
1.2 stevesk 57: .It
58: system-wide configuration file
59: .Pq Pa /etc/ssh/ssh_config
60: .El
1.1 stevesk 61: .Pp
62: For each parameter, the first obtained value
63: will be used.
1.41 jmc 64: The configuration files contain sections separated by
1.1 stevesk 65: .Dq Host
66: specifications, and that section is only applied for hosts that
67: match one of the patterns given in the specification.
68: The matched host name is the one given on the command line.
69: .Pp
70: Since the first obtained value for each parameter is used, more
71: host-specific declarations should be given near the beginning of the
72: file, and general defaults at the end.
1.80 jmc 73: .Pp
1.1 stevesk 74: The configuration file has the following format:
75: .Pp
76: Empty lines and lines starting with
77: .Ql #
78: are comments.
79: Otherwise a line is of the format
80: .Dq keyword arguments .
81: Configuration options may be separated by whitespace or
82: optional whitespace and exactly one
83: .Ql = ;
84: the latter format is useful to avoid the need to quote whitespace
85: when specifying configuration options using the
86: .Nm ssh ,
1.87 jmc 87: .Nm scp ,
1.1 stevesk 88: and
89: .Nm sftp
90: .Fl o
91: option.
1.88 dtucker 92: Arguments may optionally be enclosed in double quotes
93: .Pq \&"
94: in order to represent arguments containing spaces.
1.1 stevesk 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.
1.112 krw 105: If more than one pattern is provided, they should be separated by whitespace.
1.1 stevesk 106: A single
1.83 jmc 107: .Ql *
1.1 stevesk 108: as a pattern can be used to provide global
109: defaults for all hosts.
110: The host is the
111: .Ar hostname
1.83 jmc 112: argument given on the command line (i.e. the name is not converted to
1.1 stevesk 113: a canonicalized host name before matching).
1.148 djm 114: .Pp
115: A pattern entry may be negated by prefixing it with an exclamation mark
116: .Pq Sq !\& .
117: If a negated entry is matched, then the
118: .Cm Host
119: entry is ignored, regardless of whether any other patterns on the line
120: match.
121: Negated matches are therefore useful to provide exceptions for wildcard
122: matches.
1.81 jmc 123: .Pp
124: See
125: .Sx PATTERNS
126: for more information on patterns.
1.10 djm 127: .It Cm AddressFamily
1.11 jmc 128: Specifies which address family to use when connecting.
129: Valid arguments are
1.10 djm 130: .Dq any ,
131: .Dq inet
1.84 jmc 132: (use IPv4 only), or
1.10 djm 133: .Dq inet6
1.40 jmc 134: (use IPv6 only).
1.1 stevesk 135: .It Cm BatchMode
136: If set to
137: .Dq yes ,
138: passphrase/password querying will be disabled.
139: This option is useful in scripts and other batch jobs where no user
140: is present to supply the password.
141: The argument must be
142: .Dq yes
143: or
144: .Dq no .
145: The default is
146: .Dq no .
147: .It Cm BindAddress
1.60 dtucker 148: Use the specified address on the local machine as the source address of
1.61 jmc 149: the connection.
150: Only useful on systems with more than one address.
1.1 stevesk 151: Note that this option does not work if
152: .Cm UsePrivilegedPort
153: is set to
154: .Dq yes .
155: .It Cm ChallengeResponseAuthentication
1.82 jmc 156: Specifies whether to use challenge-response authentication.
1.1 stevesk 157: The argument to this keyword must be
158: .Dq yes
159: or
160: .Dq no .
161: The default is
162: .Dq yes .
163: .It Cm CheckHostIP
164: If this flag is set to
165: .Dq yes ,
1.84 jmc 166: .Xr ssh 1
167: will additionally check the host IP address in the
1.1 stevesk 168: .Pa known_hosts
169: file.
170: This allows ssh to detect if a host key changed due to DNS spoofing.
1.107 grunk 171: If the option is set to
1.1 stevesk 172: .Dq no ,
173: the check will not be executed.
174: The default is
175: .Dq yes .
176: .It Cm Cipher
177: Specifies the cipher to use for encrypting the session
178: in protocol version 1.
179: Currently,
180: .Dq blowfish ,
181: .Dq 3des ,
182: and
183: .Dq des
184: are supported.
185: .Ar des
186: is only supported in the
1.84 jmc 187: .Xr ssh 1
1.1 stevesk 188: client for interoperability with legacy protocol 1 implementations
189: that do not support the
190: .Ar 3des
1.7 jmc 191: cipher.
192: Its use is strongly discouraged due to cryptographic weaknesses.
1.1 stevesk 193: The default is
194: .Dq 3des .
195: .It Cm Ciphers
196: Specifies the ciphers allowed for protocol version 2
197: in order of preference.
198: Multiple ciphers must be comma-separated.
1.35 dtucker 199: The supported ciphers are
200: .Dq 3des-cbc ,
201: .Dq aes128-cbc ,
202: .Dq aes192-cbc ,
203: .Dq aes256-cbc ,
204: .Dq aes128-ctr ,
205: .Dq aes192-ctr ,
206: .Dq aes256-ctr ,
1.54 djm 207: .Dq arcfour128 ,
208: .Dq arcfour256 ,
1.35 dtucker 209: .Dq arcfour ,
210: .Dq blowfish-cbc ,
211: and
212: .Dq cast128-cbc .
1.84 jmc 213: The default is:
214: .Bd -literal -offset 3n
1.116 naddy 215: aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,
216: aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,
217: aes256-cbc,arcfour
1.1 stevesk 218: .Ed
219: .It Cm ClearAllForwardings
1.84 jmc 220: Specifies that all local, remote, and dynamic port forwardings
1.1 stevesk 221: specified in the configuration files or on the command line be
1.7 jmc 222: cleared.
223: This option is primarily useful when used from the
1.84 jmc 224: .Xr ssh 1
1.1 stevesk 225: command line to clear port forwardings set in
226: configuration files, and is automatically set by
227: .Xr scp 1
228: and
229: .Xr sftp 1 .
230: The argument must be
231: .Dq yes
232: or
233: .Dq no .
234: The default is
235: .Dq no .
236: .It Cm Compression
237: Specifies whether to use compression.
238: The argument must be
239: .Dq yes
240: or
241: .Dq no .
242: The default is
243: .Dq no .
244: .It Cm CompressionLevel
245: Specifies the compression level to use if compression is enabled.
246: The argument must be an integer from 1 (fast) to 9 (slow, best).
247: The default level is 6, which is good for most applications.
248: The meaning of the values is the same as in
249: .Xr gzip 1 .
250: Note that this option applies to protocol version 1 only.
251: .It Cm ConnectionAttempts
252: Specifies the number of tries (one per second) to make before exiting.
253: The argument must be an integer.
254: This may be useful in scripts if the connection sometimes fails.
255: The default is 1.
1.9 djm 256: .It Cm ConnectTimeout
1.84 jmc 257: Specifies the timeout (in seconds) used when connecting to the
258: SSH server, instead of using the default system TCP timeout.
1.11 jmc 259: This value is used only when the target is down or really unreachable,
260: not when it refuses the connection.
1.36 djm 261: .It Cm ControlMaster
262: Enables the sharing of multiple sessions over a single network connection.
263: When set to
1.84 jmc 264: .Dq yes ,
265: .Xr ssh 1
1.36 djm 266: will listen for connections on a control socket specified using the
267: .Cm ControlPath
268: argument.
269: Additional sessions can connect to this socket using the same
270: .Cm ControlPath
271: with
272: .Cm ControlMaster
273: set to
274: .Dq no
1.38 jmc 275: (the default).
1.64 jmc 276: These sessions will try to reuse the master instance's network connection
1.63 djm 277: rather than initiating new ones, but will fall back to connecting normally
278: if the control socket does not exist, or is not listening.
279: .Pp
1.37 djm 280: Setting this to
281: .Dq ask
1.84 jmc 282: will cause ssh
1.37 djm 283: to listen for control connections, but require confirmation using the
284: .Ev SSH_ASKPASS
285: program before they are accepted (see
286: .Xr ssh-add 1
1.38 jmc 287: for details).
1.51 jakob 288: If the
289: .Cm ControlPath
1.84 jmc 290: cannot be opened,
291: ssh will continue without connecting to a master instance.
1.58 djm 292: .Pp
293: X11 and
1.59 jmc 294: .Xr ssh-agent 1
1.58 djm 295: forwarding is supported over these multiplexed connections, however the
1.70 stevesk 296: display and agent forwarded will be the one belonging to the master
1.59 jmc 297: connection i.e. it is not possible to forward multiple displays or agents.
1.56 djm 298: .Pp
299: Two additional options allow for opportunistic multiplexing: try to use a
300: master connection but fall back to creating a new one if one does not already
301: exist.
302: These options are:
303: .Dq auto
304: and
305: .Dq autoask .
306: The latter requires confirmation like the
307: .Dq ask
308: option.
1.36 djm 309: .It Cm ControlPath
1.55 djm 310: Specify the path to the control socket used for connection sharing as described
311: in the
1.36 djm 312: .Cm ControlMaster
1.57 djm 313: section above or the string
314: .Dq none
315: to disable connection sharing.
1.55 djm 316: In the path,
1.147 djm 317: .Ql %L
318: will be substituted by the first component of the local host name,
1.77 djm 319: .Ql %l
1.147 djm 320: will be substituted by the local host name (including any domain name),
1.55 djm 321: .Ql %h
322: will be substituted by the target host name,
1.150 jmc 323: .Ql %n
324: will be substituted by the original target host name
325: specified on the command line,
1.55 djm 326: .Ql %p
1.147 djm 327: the port,
1.55 djm 328: .Ql %r
1.147 djm 329: by the remote login username, and
330: .Ql %u
331: by the username of the user running
332: .Xr ssh 1 .
1.56 djm 333: It is recommended that any
334: .Cm ControlPath
335: used for opportunistic connection sharing include
1.78 jmc 336: at least %h, %p, and %r.
1.56 djm 337: This ensures that shared connections are uniquely identified.
1.137 djm 338: .It Cm ControlPersist
339: When used in conjunction with
340: .Cm ControlMaster ,
341: specifies that the master connection should remain open
342: in the background (waiting for future client connections)
343: after the initial client connection has been closed.
344: If set to
345: .Dq no ,
346: then the master connection will not be placed into the background,
347: and will close as soon as the initial client connection is closed.
348: If set to
349: .Dq yes ,
350: then the master connection will remain in the background indefinitely
351: (until killed or closed via a mechanism such as the
352: .Xr ssh 1
353: .Dq Fl O No exit
354: option).
355: If set to a time in seconds, or a time in any of the formats documented in
356: .Xr sshd_config 5 ,
357: then the backgrounded master connection will automatically terminate
358: after it has remained idle (with no client connections) for the
359: specified time.
1.38 jmc 360: .It Cm DynamicForward
1.74 jmc 361: Specifies that a TCP port on the local machine be forwarded
1.38 jmc 362: over the secure channel, and the application
363: protocol is then used to determine where to connect to from the
364: remote machine.
1.62 djm 365: .Pp
366: The argument must be
367: .Sm off
368: .Oo Ar bind_address : Oc Ar port .
369: .Sm on
1.138 djm 370: IPv6 addresses can be specified by enclosing addresses in square brackets.
1.62 djm 371: By default, the local port is bound in accordance with the
372: .Cm GatewayPorts
373: setting.
374: However, an explicit
375: .Ar bind_address
376: may be used to bind the connection to a specific address.
377: The
378: .Ar bind_address
379: of
380: .Dq localhost
381: indicates that the listening port be bound for local use only, while an
382: empty address or
383: .Sq *
384: indicates that the port should be available from all interfaces.
385: .Pp
1.38 jmc 386: Currently the SOCKS4 and SOCKS5 protocols are supported, and
1.84 jmc 387: .Xr ssh 1
1.38 jmc 388: will act as a SOCKS server.
389: Multiple forwardings may be specified, and
390: additional forwardings can be given on the command line.
391: Only the superuser can forward privileged ports.
1.14 markus 392: .It Cm EnableSSHKeysign
393: Setting this option to
394: .Dq yes
395: in the global client configuration file
396: .Pa /etc/ssh/ssh_config
397: enables the use of the helper program
398: .Xr ssh-keysign 8
399: during
400: .Cm HostbasedAuthentication .
401: The argument must be
402: .Dq yes
403: or
404: .Dq no .
405: The default is
406: .Dq no .
1.23 jmc 407: This option should be placed in the non-hostspecific section.
1.14 markus 408: See
409: .Xr ssh-keysign 8
410: for more information.
1.1 stevesk 411: .It Cm EscapeChar
412: Sets the escape character (default:
413: .Ql ~ ) .
414: The escape character can also
415: be set on the command line.
416: The argument should be a single character,
417: .Ql ^
418: followed by a letter, or
419: .Dq none
420: to disable the escape
421: character entirely (making the connection transparent for binary
422: data).
1.96 markus 423: .It Cm ExitOnForwardFailure
424: Specifies whether
425: .Xr ssh 1
426: should terminate the connection if it cannot set up all requested
1.102 stevesk 427: dynamic, tunnel, local, and remote port forwardings.
1.96 markus 428: The argument must be
429: .Dq yes
430: or
431: .Dq no .
432: The default is
433: .Dq no .
1.1 stevesk 434: .It Cm ForwardAgent
435: Specifies whether the connection to the authentication agent (if any)
436: will be forwarded to the remote machine.
437: The argument must be
438: .Dq yes
439: or
440: .Dq no .
441: The default is
442: .Dq no .
1.3 stevesk 443: .Pp
1.7 jmc 444: Agent forwarding should be enabled with caution.
445: Users with the ability to bypass file permissions on the remote host
446: (for the agent's Unix-domain socket)
447: can access the local agent through the forwarded connection.
448: An attacker cannot obtain key material from the agent,
1.3 stevesk 449: however they can perform operations on the keys that enable them to
450: authenticate using the identities loaded into the agent.
1.1 stevesk 451: .It Cm ForwardX11
452: Specifies whether X11 connections will be automatically redirected
453: over the secure channel and
454: .Ev DISPLAY
455: set.
456: The argument must be
457: .Dq yes
458: or
459: .Dq no .
460: The default is
461: .Dq no .
1.3 stevesk 462: .Pp
1.7 jmc 463: X11 forwarding should be enabled with caution.
464: Users with the ability to bypass file permissions on the remote host
1.22 markus 465: (for the user's X11 authorization database)
1.7 jmc 466: can access the local X11 display through the forwarded connection.
1.22 markus 467: An attacker may then be able to perform activities such as keystroke monitoring
468: if the
469: .Cm ForwardX11Trusted
470: option is also enabled.
1.134 djm 471: .It Cm ForwardX11Timeout
1.135 jmc 472: Specify a timeout for untrusted X11 forwarding
473: using the format described in the
1.134 djm 474: .Sx TIME FORMATS
475: section of
476: .Xr sshd_config 5 .
477: X11 connections received by
478: .Xr ssh 1
479: after this time will be refused.
480: The default is to disable untrusted X11 forwarding after twenty minutes has
481: elapsed.
1.22 markus 482: .It Cm ForwardX11Trusted
1.34 jmc 483: If this option is set to
1.84 jmc 484: .Dq yes ,
485: remote X11 clients will have full access to the original X11 display.
1.42 djm 486: .Pp
1.22 markus 487: If this option is set to
1.84 jmc 488: .Dq no ,
489: remote X11 clients will be considered untrusted and prevented
1.22 markus 490: from stealing or tampering with data belonging to trusted X11
491: clients.
1.42 djm 492: Furthermore, the
493: .Xr xauth 1
494: token used for the session will be set to expire after 20 minutes.
495: Remote clients will be refused access after this time.
1.22 markus 496: .Pp
497: The default is
498: .Dq no .
499: .Pp
500: See the X11 SECURITY extension specification for full details on
501: the restrictions imposed on untrusted clients.
1.1 stevesk 502: .It Cm GatewayPorts
503: Specifies whether remote hosts are allowed to connect to local
504: forwarded ports.
505: By default,
1.84 jmc 506: .Xr ssh 1
1.7 jmc 507: binds local port forwardings to the loopback address.
508: This prevents other remote hosts from connecting to forwarded ports.
1.1 stevesk 509: .Cm GatewayPorts
1.84 jmc 510: can be used to specify that ssh
1.1 stevesk 511: should bind local port forwardings to the wildcard address,
512: thus allowing remote hosts to connect to forwarded ports.
513: The argument must be
514: .Dq yes
515: or
516: .Dq no .
517: The default is
518: .Dq no .
519: .It Cm GlobalKnownHostsFile
1.151 ! djm 520: Specifies one or more files to use for the global
! 521: host key database, separated by whitespace.
! 522: The default is
! 523: .Pa /etc/ssh/ssh_known_hosts ,
! 524: .Pa /etc/ssh/ssh_known_hosts2 .
1.18 markus 525: .It Cm GSSAPIAuthentication
1.27 markus 526: Specifies whether user authentication based on GSSAPI is allowed.
1.20 jmc 527: The default is
1.21 markus 528: .Dq no .
1.18 markus 529: Note that this option applies to protocol version 2 only.
530: .It Cm GSSAPIDelegateCredentials
531: Forward (delegate) credentials to the server.
532: The default is
533: .Dq no .
534: Note that this option applies to protocol version 2 only.
1.44 djm 535: .It Cm HashKnownHosts
536: Indicates that
1.84 jmc 537: .Xr ssh 1
1.44 djm 538: should hash host names and addresses when they are added to
1.50 djm 539: .Pa ~/.ssh/known_hosts .
1.44 djm 540: These hashed names may be used normally by
1.84 jmc 541: .Xr ssh 1
1.44 djm 542: and
1.84 jmc 543: .Xr sshd 8 ,
1.44 djm 544: but they do not reveal identifying information should the file's contents
545: be disclosed.
546: The default is
547: .Dq no .
1.97 jmc 548: Note that existing names and addresses in known hosts files
549: will not be converted automatically,
550: but may be manually hashed using
1.45 djm 551: .Xr ssh-keygen 1 .
1.1 stevesk 552: .It Cm HostbasedAuthentication
553: Specifies whether to try rhosts based authentication with public key
554: authentication.
555: The argument must be
556: .Dq yes
557: or
558: .Dq no .
559: The default is
560: .Dq no .
561: This option applies to protocol version 2 only and
562: is similar to
563: .Cm RhostsRSAAuthentication .
564: .It Cm HostKeyAlgorithms
565: Specifies the protocol version 2 host key algorithms
566: that the client wants to use in order of preference.
567: The default for this option is:
1.139 djm 568: .Bd -literal -offset 3n
569: ecdsa-sha2-nistp256-cert-v01@openssh.com,
570: ecdsa-sha2-nistp384-cert-v01@openssh.com,
571: ecdsa-sha2-nistp521-cert-v01@openssh.com,
572: ssh-rsa-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com,
573: ssh-rsa-cert-v00@openssh.com,ssh-dss-cert-v00@openssh.com,
574: ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,
575: ssh-rsa,ssh-dss
576: .Ed
1.145 djm 577: .Pp
578: If hostkeys are known for the destination host then this default is modified
579: to prefer their algorithms.
1.1 stevesk 580: .It Cm HostKeyAlias
581: Specifies an alias that should be used instead of the
582: real host name when looking up or saving the host key
583: in the host key database files.
1.84 jmc 584: This option is useful for tunneling SSH connections
1.1 stevesk 585: or for multiple servers running on a single host.
586: .It Cm HostName
587: Specifies the real host name to log into.
588: This can be used to specify nicknames or abbreviations for hosts.
1.136 djm 589: If the hostname contains the character sequence
590: .Ql %h ,
1.150 jmc 591: then this will be replaced with the host name specified on the command line
1.136 djm 592: (this is useful for manipulating unqualified names).
1.84 jmc 593: The default is the name given on the command line.
1.1 stevesk 594: Numeric IP addresses are also permitted (both on the command line and in
595: .Cm HostName
596: specifications).
1.29 markus 597: .It Cm IdentitiesOnly
598: Specifies that
1.84 jmc 599: .Xr ssh 1
1.29 markus 600: should only use the authentication identity files configured in the
1.31 jmc 601: .Nm
1.29 markus 602: files,
1.84 jmc 603: even if
604: .Xr ssh-agent 1
1.29 markus 605: offers more identities.
606: The argument to this keyword must be
607: .Dq yes
608: or
609: .Dq no .
1.84 jmc 610: This option is intended for situations where ssh-agent
1.29 markus 611: offers many different identities.
612: The default is
613: .Dq no .
1.67 jmc 614: .It Cm IdentityFile
1.139 djm 615: Specifies a file from which the user's DSA, ECDSA or DSA authentication
616: identity is read.
1.67 jmc 617: The default is
618: .Pa ~/.ssh/identity
619: for protocol version 1, and
1.139 djm 620: .Pa ~/.ssh/id_dsa ,
621: .Pa ~/.ssh/id_ecdsa
622: and
1.67 jmc 623: .Pa ~/.ssh/id_rsa
624: for protocol version 2.
625: Additionally, any identities represented by the authentication agent
626: will be used for authentication.
1.129 djm 627: .Xr ssh 1
628: will try to load certificate information from the filename obtained by
629: appending
630: .Pa -cert.pub
631: to the path of a specified
632: .Cm IdentityFile .
1.90 djm 633: .Pp
1.67 jmc 634: The file name may use the tilde
1.91 jmc 635: syntax to refer to a user's home directory or one of the following
1.90 djm 636: escape characters:
637: .Ql %d
638: (local user's home directory),
639: .Ql %u
640: (local user name),
641: .Ql %l
642: (local host name),
643: .Ql %h
644: (remote host name) or
1.92 djm 645: .Ql %r
1.90 djm 646: (remote user name).
647: .Pp
1.67 jmc 648: It is possible to have
649: multiple identity files specified in configuration files; all these
650: identities will be tried in sequence.
1.143 djm 651: .It Cm IPQoS
652: Specifies the IPv4 type-of-service or DSCP class for connections.
653: Accepted values are
654: .Dq af11 ,
655: .Dq af12 ,
656: .Dq af13 ,
657: .Dq af14 ,
658: .Dq af22 ,
659: .Dq af23 ,
660: .Dq af31 ,
661: .Dq af32 ,
662: .Dq af33 ,
663: .Dq af41 ,
664: .Dq af42 ,
665: .Dq af43 ,
666: .Dq cs0 ,
667: .Dq cs1 ,
668: .Dq cs2 ,
669: .Dq cs3 ,
670: .Dq cs4 ,
671: .Dq cs5 ,
672: .Dq cs6 ,
673: .Dq cs7 ,
674: .Dq ef ,
675: .Dq lowdelay ,
676: .Dq throughput ,
677: .Dq reliability ,
678: or a numeric value.
1.146 djm 679: This option may take one or two arguments, separated by whitespace.
1.143 djm 680: If one argument is specified, it is used as the packet class unconditionally.
681: If two values are specified, the first is automatically selected for
682: interactive sessions and the second for non-interactive sessions.
683: The default is
684: .Dq lowdelay
685: for interactive sessions and
686: .Dq throughput
687: for non-interactive sessions.
1.103 djm 688: .It Cm KbdInteractiveAuthentication
689: Specifies whether to use keyboard-interactive authentication.
690: The argument to this keyword must be
691: .Dq yes
692: or
693: .Dq no .
694: The default is
695: .Dq yes .
1.39 djm 696: .It Cm KbdInteractiveDevices
697: Specifies the list of methods to use in keyboard-interactive authentication.
698: Multiple method names must be comma-separated.
699: The default is to use the server specified list.
1.85 jmc 700: The methods available vary depending on what the server supports.
701: For an OpenSSH server,
702: it may be zero or more of:
703: .Dq bsdauth ,
704: .Dq pam ,
705: and
706: .Dq skey .
1.140 djm 707: .It Cm KexAlgorithms
708: Specifies the available KEX (Key Exchange) algorithms.
709: Multiple algorithms must be comma-separated.
1.141 jmc 710: The default is:
711: .Bd -literal -offset indent
712: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,
713: diffie-hellman-group-exchange-sha256,
714: diffie-hellman-group-exchange-sha1,
715: diffie-hellman-group14-sha1,
716: diffie-hellman-group1-sha1
717: .Ed
1.65 reyk 718: .It Cm LocalCommand
719: Specifies a command to execute on the local machine after successfully
720: connecting to the server.
721: The command string extends to the end of the line, and is executed with
1.105 jmc 722: the user's shell.
1.109 dtucker 723: The following escape character substitutions will be performed:
724: .Ql %d
725: (local user's home directory),
726: .Ql %h
727: (remote host name),
728: .Ql %l
729: (local host name),
730: .Ql %n
731: (host name as provided on the command line),
732: .Ql %p
733: (remote port),
734: .Ql %r
735: (remote user name) or
736: .Ql %u
737: (local user name).
1.123 djm 738: .Pp
739: The command is run synchronously and does not have access to the
740: session of the
741: .Xr ssh 1
742: that spawned it.
743: It should not be used for interactive commands.
744: .Pp
1.65 reyk 745: This directive is ignored unless
746: .Cm PermitLocalCommand
747: has been enabled.
1.1 stevesk 748: .It Cm LocalForward
1.74 jmc 749: Specifies that a TCP port on the local machine be forwarded over
1.1 stevesk 750: the secure channel to the specified host and port from the remote machine.
1.49 jmc 751: The first argument must be
1.43 djm 752: .Sm off
1.49 jmc 753: .Oo Ar bind_address : Oc Ar port
1.43 djm 754: .Sm on
1.49 jmc 755: and the second argument must be
756: .Ar host : Ns Ar hostport .
1.138 djm 757: IPv6 addresses can be specified by enclosing addresses in square brackets.
1.46 jmc 758: Multiple forwardings may be specified, and additional forwardings can be
1.43 djm 759: given on the command line.
1.1 stevesk 760: Only the superuser can forward privileged ports.
1.43 djm 761: By default, the local port is bound in accordance with the
762: .Cm GatewayPorts
763: setting.
764: However, an explicit
765: .Ar bind_address
766: may be used to bind the connection to a specific address.
767: The
768: .Ar bind_address
769: of
770: .Dq localhost
1.46 jmc 771: indicates that the listening port be bound for local use only, while an
772: empty address or
773: .Sq *
1.43 djm 774: indicates that the port should be available from all interfaces.
1.1 stevesk 775: .It Cm LogLevel
776: Gives the verbosity level that is used when logging messages from
1.84 jmc 777: .Xr ssh 1 .
1.1 stevesk 778: The possible values are:
1.84 jmc 779: QUIET, FATAL, ERROR, INFO, VERBOSE, DEBUG, DEBUG1, DEBUG2, and DEBUG3.
1.7 jmc 780: The default is INFO.
781: DEBUG and DEBUG1 are equivalent.
782: DEBUG2 and DEBUG3 each specify higher levels of verbose output.
1.1 stevesk 783: .It Cm MACs
784: Specifies the MAC (message authentication code) algorithms
785: in order of preference.
786: The MAC algorithm is used in protocol version 2
787: for data integrity protection.
788: Multiple algorithms must be comma-separated.
1.84 jmc 789: The default is:
1.101 jmc 790: .Bd -literal -offset indent
791: hmac-md5,hmac-sha1,umac-64@openssh.com,
792: hmac-ripemd160,hmac-sha1-96,hmac-md5-96
793: .Ed
1.1 stevesk 794: .It Cm NoHostAuthenticationForLocalhost
795: This option can be used if the home directory is shared across machines.
796: In this case localhost will refer to a different machine on each of
797: the machines and the user will get many warnings about changed host keys.
798: However, this option disables host authentication for localhost.
799: The argument to this keyword must be
800: .Dq yes
801: or
802: .Dq no .
803: The default is to check the host key for localhost.
804: .It Cm NumberOfPasswordPrompts
805: Specifies the number of password prompts before giving up.
806: The argument to this keyword must be an integer.
1.84 jmc 807: The default is 3.
1.1 stevesk 808: .It Cm PasswordAuthentication
809: Specifies whether to use password authentication.
810: The argument to this keyword must be
811: .Dq yes
812: or
813: .Dq no .
814: The default is
815: .Dq yes .
1.65 reyk 816: .It Cm PermitLocalCommand
817: Allow local command execution via the
818: .Ic LocalCommand
819: option or using the
1.66 jmc 820: .Ic !\& Ns Ar command
1.65 reyk 821: escape sequence in
822: .Xr ssh 1 .
823: The argument must be
824: .Dq yes
825: or
826: .Dq no .
827: The default is
828: .Dq no .
1.127 markus 829: .It Cm PKCS11Provider
830: Specifies which PKCS#11 provider to use.
1.144 jmc 831: The argument to this keyword is the PKCS#11 shared library
1.127 markus 832: .Xr ssh 1
1.128 markus 833: should use to communicate with a PKCS#11 token providing the user's
1.127 markus 834: private RSA key.
1.67 jmc 835: .It Cm Port
836: Specifies the port number to connect on the remote host.
1.84 jmc 837: The default is 22.
1.1 stevesk 838: .It Cm PreferredAuthentications
839: Specifies the order in which the client should try protocol 2
1.11 jmc 840: authentication methods.
1.48 jmc 841: This allows a client to prefer one method (e.g.\&
1.1 stevesk 842: .Cm keyboard-interactive )
1.48 jmc 843: over another method (e.g.\&
1.131 jmc 844: .Cm password ) .
845: The default is:
846: .Bd -literal -offset indent
847: gssapi-with-mic,hostbased,publickey,
848: keyboard-interactive,password
849: .Ed
1.1 stevesk 850: .It Cm Protocol
851: Specifies the protocol versions
1.84 jmc 852: .Xr ssh 1
1.1 stevesk 853: should support in order of preference.
854: The possible values are
1.84 jmc 855: .Sq 1
1.1 stevesk 856: and
1.84 jmc 857: .Sq 2 .
1.1 stevesk 858: Multiple versions must be comma-separated.
1.120 markus 859: When this option is set to
1.121 jmc 860: .Dq 2,1
1.120 markus 861: .Nm ssh
862: will try version 2 and fall back to version 1
863: if version 2 is not available.
1.1 stevesk 864: The default is
1.121 jmc 865: .Sq 2 .
1.1 stevesk 866: .It Cm ProxyCommand
867: Specifies the command to use to connect to the server.
868: The command
869: string extends to the end of the line, and is executed with
1.105 jmc 870: the user's shell.
1.133 jmc 871: In the command string, any occurrence of
1.1 stevesk 872: .Ql %h
873: will be substituted by the host name to
1.132 djm 874: connect,
1.1 stevesk 875: .Ql %p
1.133 jmc 876: by the port, and
877: .Ql %r
1.132 djm 878: by the remote user name.
1.1 stevesk 879: The command can be basically anything,
880: and should read from its standard input and write to its standard output.
881: It should eventually connect an
882: .Xr sshd 8
883: server running on some machine, or execute
884: .Ic sshd -i
885: somewhere.
886: Host key management will be done using the
887: HostName of the host being connected (defaulting to the name typed by
888: the user).
1.7 jmc 889: Setting the command to
890: .Dq none
1.6 markus 891: disables this option entirely.
1.1 stevesk 892: Note that
893: .Cm CheckHostIP
894: is not available for connects with a proxy command.
1.52 djm 895: .Pp
896: This directive is useful in conjunction with
897: .Xr nc 1
898: and its proxy support.
1.53 jmc 899: For example, the following directive would connect via an HTTP proxy at
1.52 djm 900: 192.0.2.0:
901: .Bd -literal -offset 3n
902: ProxyCommand /usr/bin/nc -X connect -x 192.0.2.0:8080 %h %p
903: .Ed
1.1 stevesk 904: .It Cm PubkeyAuthentication
905: Specifies whether to try public key authentication.
906: The argument to this keyword must be
907: .Dq yes
908: or
909: .Dq no .
910: The default is
911: .Dq yes .
912: This option applies to protocol version 2 only.
1.75 dtucker 913: .It Cm RekeyLimit
914: Specifies the maximum amount of data that may be transmitted before the
1.76 jmc 915: session key is renegotiated.
1.75 dtucker 916: The argument is the number of bytes, with an optional suffix of
1.76 jmc 917: .Sq K ,
918: .Sq M ,
1.75 dtucker 919: or
1.76 jmc 920: .Sq G
1.75 dtucker 921: to indicate Kilobytes, Megabytes, or Gigabytes, respectively.
922: The default is between
1.84 jmc 923: .Sq 1G
1.75 dtucker 924: and
1.84 jmc 925: .Sq 4G ,
1.75 dtucker 926: depending on the cipher.
1.76 jmc 927: This option applies to protocol version 2 only.
1.1 stevesk 928: .It Cm RemoteForward
1.74 jmc 929: Specifies that a TCP port on the remote machine be forwarded over
1.1 stevesk 930: the secure channel to the specified host and port from the local machine.
1.49 jmc 931: The first argument must be
1.43 djm 932: .Sm off
1.49 jmc 933: .Oo Ar bind_address : Oc Ar port
1.43 djm 934: .Sm on
1.49 jmc 935: and the second argument must be
936: .Ar host : Ns Ar hostport .
1.138 djm 937: IPv6 addresses can be specified by enclosing addresses in square brackets.
1.1 stevesk 938: Multiple forwardings may be specified, and additional
939: forwardings can be given on the command line.
1.113 stevesk 940: Privileged ports can be forwarded only when
941: logging in as root on the remote machine.
1.118 jmc 942: .Pp
1.117 djm 943: If the
944: .Ar port
945: argument is
946: .Ql 0 ,
947: the listen port will be dynamically allocated on the server and reported
948: to the client at run time.
1.43 djm 949: .Pp
950: If the
951: .Ar bind_address
952: is not specified, the default is to only bind to loopback addresses.
953: If the
954: .Ar bind_address
955: is
956: .Ql *
957: or an empty string, then the forwarding is requested to listen on all
958: interfaces.
959: Specifying a remote
960: .Ar bind_address
1.46 jmc 961: will only succeed if the server's
962: .Cm GatewayPorts
1.43 djm 963: option is enabled (see
1.46 jmc 964: .Xr sshd_config 5 ) .
1.149 djm 965: .It Cm RequestTTY
966: Specifies whether to request a pseudo-tty for the session.
967: The argument may be one of:
968: .Dq no
969: (never request a TTY),
970: .Dq yes
971: (always request a TTY when standard input is a TTY),
972: .Dq force
973: (always request a TTY) or
974: .Dq auto
975: (request a TTY when opening a login session).
976: This option mirrors the
977: .Fl t
978: and
979: .Fl T
980: flags for
981: .Xr ssh 1 .
1.1 stevesk 982: .It Cm RhostsRSAAuthentication
983: Specifies whether to try rhosts based authentication with RSA host
984: authentication.
985: The argument must be
986: .Dq yes
987: or
988: .Dq no .
989: The default is
990: .Dq no .
991: This option applies to protocol version 1 only and requires
1.84 jmc 992: .Xr ssh 1
1.1 stevesk 993: to be setuid root.
994: .It Cm RSAAuthentication
995: Specifies whether to try RSA authentication.
996: The argument to this keyword must be
997: .Dq yes
998: or
999: .Dq no .
1000: RSA authentication will only be
1001: attempted if the identity file exists, or an authentication agent is
1002: running.
1003: The default is
1004: .Dq yes .
1005: Note that this option applies to protocol version 1 only.
1.32 djm 1006: .It Cm SendEnv
1007: Specifies what variables from the local
1008: .Xr environ 7
1009: should be sent to the server.
1.84 jmc 1010: Note that environment passing is only supported for protocol 2.
1011: The server must also support it, and the server must be configured to
1.33 djm 1012: accept these environment variables.
1.32 djm 1013: Refer to
1014: .Cm AcceptEnv
1015: in
1016: .Xr sshd_config 5
1017: for how to configure the server.
1.80 jmc 1018: Variables are specified by name, which may contain wildcard characters.
1.33 djm 1019: Multiple environment variables may be separated by whitespace or spread
1.32 djm 1020: across multiple
1021: .Cm SendEnv
1022: directives.
1023: The default is not to send any environment variables.
1.81 jmc 1024: .Pp
1025: See
1026: .Sx PATTERNS
1027: for more information on patterns.
1.28 markus 1028: .It Cm ServerAliveCountMax
1.73 jmc 1029: Sets the number of server alive messages (see below) which may be
1.28 markus 1030: sent without
1.84 jmc 1031: .Xr ssh 1
1.28 markus 1032: receiving any messages back from the server.
1033: If this threshold is reached while server alive messages are being sent,
1.84 jmc 1034: ssh will disconnect from the server, terminating the session.
1.28 markus 1035: It is important to note that the use of server alive messages is very
1036: different from
1037: .Cm TCPKeepAlive
1038: (below).
1039: The server alive messages are sent through the encrypted channel
1040: and therefore will not be spoofable.
1041: The TCP keepalive option enabled by
1042: .Cm TCPKeepAlive
1043: is spoofable.
1044: The server alive mechanism is valuable when the client or
1045: server depend on knowing when a connection has become inactive.
1046: .Pp
1047: The default value is 3.
1048: If, for example,
1049: .Cm ServerAliveInterval
1.84 jmc 1050: (see below) is set to 15 and
1.28 markus 1051: .Cm ServerAliveCountMax
1.84 jmc 1052: is left at the default, if the server becomes unresponsive,
1053: ssh will disconnect after approximately 45 seconds.
1.89 markus 1054: This option applies to protocol version 2 only.
1.67 jmc 1055: .It Cm ServerAliveInterval
1056: Sets a timeout interval in seconds after which if no data has been received
1057: from the server,
1.84 jmc 1058: .Xr ssh 1
1.67 jmc 1059: will send a message through the encrypted
1060: channel to request a response from the server.
1061: The default
1062: is 0, indicating that these messages will not be sent to the server.
1063: This option applies to protocol version 2 only.
1.1 stevesk 1064: .It Cm StrictHostKeyChecking
1065: If this flag is set to
1066: .Dq yes ,
1.84 jmc 1067: .Xr ssh 1
1.1 stevesk 1068: will never automatically add host keys to the
1.50 djm 1069: .Pa ~/.ssh/known_hosts
1.1 stevesk 1070: file, and refuses to connect to hosts whose host key has changed.
1071: This provides maximum protection against trojan horse attacks,
1.84 jmc 1072: though it can be annoying when the
1.1 stevesk 1073: .Pa /etc/ssh/ssh_known_hosts
1.84 jmc 1074: file is poorly maintained or when connections to new hosts are
1.1 stevesk 1075: frequently made.
1076: This option forces the user to manually
1077: add all new hosts.
1078: If this flag is set to
1079: .Dq no ,
1.84 jmc 1080: ssh will automatically add new host keys to the
1.1 stevesk 1081: user known hosts files.
1082: If this flag is set to
1083: .Dq ask ,
1084: new host keys
1085: will be added to the user known host files only after the user
1086: has confirmed that is what they really want to do, and
1.84 jmc 1087: ssh will refuse to connect to hosts whose host key has changed.
1.1 stevesk 1088: The host keys of
1089: known hosts will be verified automatically in all cases.
1090: The argument must be
1091: .Dq yes ,
1.84 jmc 1092: .Dq no ,
1.1 stevesk 1093: or
1094: .Dq ask .
1095: The default is
1096: .Dq ask .
1.26 markus 1097: .It Cm TCPKeepAlive
1098: Specifies whether the system should send TCP keepalive messages to the
1099: other side.
1100: If they are sent, death of the connection or crash of one
1101: of the machines will be properly noticed.
1102: However, this means that
1103: connections will die if the route is down temporarily, and some people
1104: find it annoying.
1105: .Pp
1106: The default is
1107: .Dq yes
1108: (to send TCP keepalive messages), and the client will notice
1109: if the network goes down or the remote host dies.
1110: This is important in scripts, and many users want it too.
1111: .Pp
1112: To disable TCP keepalive messages, the value should be set to
1113: .Dq no .
1.65 reyk 1114: .It Cm Tunnel
1.95 stevesk 1115: Request
1.65 reyk 1116: .Xr tun 4
1.69 jmc 1117: device forwarding between the client and the server.
1.65 reyk 1118: The argument must be
1.68 reyk 1119: .Dq yes ,
1.95 stevesk 1120: .Dq point-to-point
1121: (layer 3),
1122: .Dq ethernet
1123: (layer 2),
1.65 reyk 1124: or
1125: .Dq no .
1.95 stevesk 1126: Specifying
1127: .Dq yes
1128: requests the default tunnel mode, which is
1129: .Dq point-to-point .
1.65 reyk 1130: The default is
1131: .Dq no .
1132: .It Cm TunnelDevice
1.95 stevesk 1133: Specifies the
1.65 reyk 1134: .Xr tun 4
1.95 stevesk 1135: devices to open on the client
1136: .Pq Ar local_tun
1137: and the server
1138: .Pq Ar remote_tun .
1139: .Pp
1140: The argument must be
1141: .Sm off
1142: .Ar local_tun Op : Ar remote_tun .
1143: .Sm on
1144: The devices may be specified by numerical ID or the keyword
1145: .Dq any ,
1146: which uses the next available tunnel device.
1147: If
1148: .Ar remote_tun
1149: is not specified, it defaults to
1150: .Dq any .
1151: The default is
1152: .Dq any:any .
1.72 jmc 1153: .It Cm UsePrivilegedPort
1154: Specifies whether to use a privileged port for outgoing connections.
1155: The argument must be
1156: .Dq yes
1157: or
1158: .Dq no .
1159: The default is
1160: .Dq no .
1161: If set to
1.84 jmc 1162: .Dq yes ,
1163: .Xr ssh 1
1.72 jmc 1164: must be setuid root.
1165: Note that this option must be set to
1166: .Dq yes
1167: for
1168: .Cm RhostsRSAAuthentication
1169: with older servers.
1.1 stevesk 1170: .It Cm User
1171: Specifies the user to log in as.
1172: This can be useful when a different user name is used on different machines.
1173: This saves the trouble of
1174: having to remember to give the user name on the command line.
1175: .It Cm UserKnownHostsFile
1.151 ! djm 1176: Specifies one or more files to use for the user
! 1177: host key database, separated by whitespace.
! 1178: The default is
! 1179: .Pa ~/.ssh/known_hosts ,
! 1180: .Pa ~/.ssh/known_hosts2 .
1.8 jakob 1181: .It Cm VerifyHostKeyDNS
1182: Specifies whether to verify the remote key using DNS and SSHFP resource
1183: records.
1.24 jakob 1184: If this option is set to
1185: .Dq yes ,
1.25 jmc 1186: the client will implicitly trust keys that match a secure fingerprint
1.24 jakob 1187: from DNS.
1188: Insecure fingerprints will be handled as if this option was set to
1189: .Dq ask .
1190: If this option is set to
1191: .Dq ask ,
1192: information on fingerprint match will be displayed, but the user will still
1193: need to confirm new host keys according to the
1194: .Cm StrictHostKeyChecking
1195: option.
1196: The argument must be
1197: .Dq yes ,
1.84 jmc 1198: .Dq no ,
1.25 jmc 1199: or
1200: .Dq ask .
1.8 jakob 1201: The default is
1202: .Dq no .
1.12 jakob 1203: Note that this option applies to protocol version 2 only.
1.84 jmc 1204: .Pp
1205: See also
1206: .Sx VERIFYING HOST KEYS
1207: in
1208: .Xr ssh 1 .
1.111 grunk 1209: .It Cm VisualHostKey
1210: If this flag is set to
1211: .Dq yes ,
1212: an ASCII art representation of the remote host key fingerprint is
1.114 stevesk 1213: printed in addition to the hex fingerprint string at login and
1214: for unknown host keys.
1.111 grunk 1215: If this flag is set to
1216: .Dq no ,
1.114 stevesk 1217: no fingerprint strings are printed at login and
1218: only the hex fingerprint string will be printed for unknown host keys.
1.111 grunk 1219: The default is
1220: .Dq no .
1.1 stevesk 1221: .It Cm XAuthLocation
1.5 stevesk 1222: Specifies the full pathname of the
1.1 stevesk 1223: .Xr xauth 1
1224: program.
1225: The default is
1226: .Pa /usr/X11R6/bin/xauth .
1227: .El
1.86 jmc 1228: .Sh PATTERNS
1229: A
1230: .Em pattern
1231: consists of zero or more non-whitespace characters,
1232: .Sq *
1233: (a wildcard that matches zero or more characters),
1234: or
1235: .Sq ?\&
1236: (a wildcard that matches exactly one character).
1237: For example, to specify a set of declarations for any host in the
1238: .Dq .co.uk
1239: set of domains,
1240: the following pattern could be used:
1241: .Pp
1242: .Dl Host *.co.uk
1243: .Pp
1244: The following pattern
1245: would match any host in the 192.168.0.[0-9] network range:
1246: .Pp
1247: .Dl Host 192.168.0.?
1248: .Pp
1249: A
1250: .Em pattern-list
1251: is a comma-separated list of patterns.
1252: Patterns within pattern-lists may be negated
1253: by preceding them with an exclamation mark
1254: .Pq Sq !\& .
1255: For example,
1256: to allow a key to be used from anywhere within an organisation
1257: except from the
1258: .Dq dialup
1259: pool,
1260: the following entry (in authorized_keys) could be used:
1261: .Pp
1262: .Dl from=\&"!*.dialup.example.com,*.example.com\&"
1.1 stevesk 1263: .Sh FILES
1264: .Bl -tag -width Ds
1.50 djm 1265: .It Pa ~/.ssh/config
1.1 stevesk 1266: This is the per-user configuration file.
1267: The format of this file is described above.
1.84 jmc 1268: This file is used by the SSH client.
1.30 djm 1269: Because of the potential for abuse, this file must have strict permissions:
1270: read/write for the user, and not accessible by others.
1.1 stevesk 1271: .It Pa /etc/ssh/ssh_config
1272: Systemwide configuration file.
1273: This file provides defaults for those
1274: values that are not specified in the user's configuration file, and
1275: for those users who do not have a configuration file.
1276: This file must be world-readable.
1277: .El
1.13 jmc 1278: .Sh SEE ALSO
1279: .Xr ssh 1
1.1 stevesk 1280: .Sh AUTHORS
1281: OpenSSH is a derivative of the original and free
1282: ssh 1.2.12 release by Tatu Ylonen.
1283: Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
1284: Theo de Raadt and Dug Song
1285: removed many bugs, re-added newer features and
1286: created OpenSSH.
1287: Markus Friedl contributed the support for SSH
1288: protocol versions 1.5 and 2.0.
![[BACK]](/icons/back.gif){kind=icon}
Return to ssh_config.5 CVS log ![[TXT]](/icons/text.gif){kind=icon}
![[DIR]](/icons/dir.gif){kind=icon}
Up to [local] / src / usr.bin / ssh