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authorColin Watson <cjwatson@debian.org>2003-09-01 00:45:47 +0000
committerColin Watson <cjwatson@debian.org>2003-09-01 00:45:47 +0000
commitd984a3c6658e950881edcfb2aae464add93f68d4 (patch)
treeed2052b4001227cf8179393cba172ae470e6c097 /ssh.0
parent3e36f9f4fff8f5b573f163eecd12a677ce66fe89 (diff)
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1SSH(1) System General Commands Manual SSH(1)
2
3NAME
4 ssh - OpenSSH SSH client (remote login program)
5
6SYNOPSIS
7 ssh [-l login_name] hostname | user@hostname [command]
8
9 ssh [-afgknqstvxACNPTX1246] [-b bind_address] [-c cipher_spec]
10 [-e escape_char] [-i identity_file] [-l login_name] [-m mac_spec]
11 [-o option] [-p port] [-F configfile] [-L port:host:hostport] [-R
12 port:host:hostport] [-D port] hostname | user@hostname [command]
13
14DESCRIPTION
15 ssh (SSH client) is a program for logging into a remote machine and for
16 executing commands on a remote machine. It is intended to replace rlogin
17 and rsh, and provide secure encrypted communications between two
18 untrusted hosts over an insecure network. X11 connections and arbitrary
19 TCP/IP ports can also be forwarded over the secure channel.
20
21 ssh connects and logs into the specified hostname. The user must prove
22 his/her identity to the remote machine using one of several methods
23 depending on the protocol version used:
24
25 SSH protocol version 1
26
27 First, if the machine the user logs in from is listed in /etc/hosts.equiv
28 or /etc/shosts.equiv on the remote machine, and the user names are the
29 same on both sides, the user is immediately permitted to log in. Second,
30 if .rhosts or .shosts exists in the user's home directory on the remote
31 machine and contains a line containing the name of the client machine and
32 the name of the user on that machine, the user is permitted to log in.
33 This form of authentication alone is normally not allowed by the server
34 because it is not secure.
35
36 The second authentication method is the rhosts or hosts.equiv method comM--
37 bined with RSA-based host authentication. It means that if the login
38 would be permitted by $HOME/.rhosts, $HOME/.shosts, /etc/hosts.equiv, or
39 /etc/shosts.equiv, and if additionally the server can verify the client's
40 host key (see /etc/ssh/ssh_known_hosts and $HOME/.ssh/known_hosts in the
41 FILES section), only then login is permitted. This authentication method
42 closes security holes due to IP spoofing, DNS spoofing and routing spoofM--
43 ing. [Note to the administrator: /etc/hosts.equiv, $HOME/.rhosts, and
44 the rlogin/rsh protocol in general, are inherently insecure and should be
45 disabled if security is desired.]
46
47 As a third authentication method, ssh supports RSA based authentication.
48 The scheme is based on public-key cryptography: there are cryptosystems
49 where encryption and decryption are done using separate keys, and it is
50 not possible to derive the decryption key from the encryption key. RSA
51 is one such system. The idea is that each user creates a public/private
52 key pair for authentication purposes. The server knows the public key,
53 and only the user knows the private key. The file
54 $HOME/.ssh/authorized_keys lists the public keys that are permitted for
55 logging in. When the user logs in, the ssh program tells the server
56 which key pair it would like to use for authentication. The server
57 checks if this key is permitted, and if so, sends the user (actually the
58 ssh program running on behalf of the user) a challenge, a random number,
59 encrypted by the user's public key. The challenge can only be decrypted
60 using the proper private key. The user's client then decrypts the chalM--
61 lenge using the private key, proving that he/she knows the private key
62 but without disclosing it to the server.
63
64 ssh implements the RSA authentication protocol automatically. The user
65 creates his/her RSA key pair by running ssh-keygen(1). This stores the
66 private key in $HOME/.ssh/identity and the public key in
67 $HOME/.ssh/identity.pub in the user's home directory. The user should
68 then copy the identity.pub to $HOME/.ssh/authorized_keys in his/her home
69 directory on the remote machine (the authorized_keys file corresponds to
70 the conventional $HOME/.rhosts file, and has one key per line, though the
71 lines can be very long). After this, the user can log in without giving
72 the password. RSA authentication is much more secure than rhosts authenM--
73 tication.
74
75 The most convenient way to use RSA authentication may be with an authenM--
76 tication agent. See ssh-agent(1) for more information.
77
78 If other authentication methods fail, ssh prompts the user for a passM--
79 word. The password is sent to the remote host for checking; however,
80 since all communications are encrypted, the password cannot be seen by
81 someone listening on the network.
82
83 SSH protocol version 2
84
85 When a user connects using protocol version 2 similar authentication
86 methods are available. Using the default values for
87 PreferredAuthentications, the client will try to authenticate first using
88 the hostbased method; if this method fails public key authentication is
89 attempted, and finally if this method fails keyboard-interactive and
90 password authentication are tried.
91
92 The public key method is similar to RSA authentication described in the
93 previous section and allows the RSA or DSA algorithm to be used: The
94 client uses his private key, $HOME/.ssh/id_dsa or $HOME/.ssh/id_rsa, to
95 sign the session identifier and sends the result to the server. The
96 server checks whether the matching public key is listed in
97 $HOME/.ssh/authorized_keys and grants access if both the key is found and
98 the signature is correct. The session identifier is derived from a
99 shared Diffie-Hellman value and is only known to the client and the
100 server.
101
102 If public key authentication fails or is not available a password can be
103 sent encrypted to the remote host for proving the user's identity.
104
105 Additionally, ssh supports hostbased or challenge response authenticaM--
106 tion.
107
108 Protocol 2 provides additional mechanisms for confidentiality (the trafM--
109 fic is encrypted using 3DES, Blowfish, CAST128 or Arcfour) and integrity
110 (hmac-md5, hmac-sha1). Note that protocol 1 lacks a strong mechanism for
111 ensuring the integrity of the connection.
112
113 Login session and remote execution
114
115 When the user's identity has been accepted by the server, the server
116 either executes the given command, or logs into the machine and gives the
117 user a normal shell on the remote machine. All communication with the
118 remote command or shell will be automatically encrypted.
119
120 If a pseudo-terminal has been allocated (normal login session), the user
121 may use the escape characters noted below.
122
123 If no pseudo tty has been allocated, the session is transparent and can
124 be used to reliably transfer binary data. On most systems, setting the
125 escape character to ``none'' will also make the session transparent even
126 if a tty is used.
127
128 The session terminates when the command or shell on the remote machine
129 exits and all X11 and TCP/IP connections have been closed. The exit staM--
130 tus of the remote program is returned as the exit status of ssh.
131
132 Escape Characters
133
134 When a pseudo terminal has been requested, ssh supports a number of funcM--
135 tions through the use of an escape character.
136
137 A single tilde character can be sent as ~~ or by following the tilde by a
138 character other than those described below. The escape character must
139 always follow a newline to be interpreted as special. The escape characM--
140 ter can be changed in configuration files using the EscapeChar configuraM--
141 tion directive or on the command line by the -e option.
142
143 The supported escapes (assuming the default `~') are:
144
145 ~. Disconnect
146
147 ~^Z Background ssh
148
149 ~# List forwarded connections
150
151 ~& Background ssh at logout when waiting for forwarded connection /
152 X11 sessions to terminate
153
154 ~? Display a list of escape characters
155
156 ~C Open command line (only useful for adding port forwardings using
157 the -L and -R options)
158
159 ~R Request rekeying of the connection (only useful for SSH protocol
160 version 2 and if the peer supports it)
161
162 X11 and TCP forwarding
163
164 If the ForwardX11 variable is set to ``yes'' (or, see the description of
165 the -X and -x options described later) and the user is using X11 (the
166 DISPLAY environment variable is set), the connection to the X11 display
167 is automatically forwarded to the remote side in such a way that any X11
168 programs started from the shell (or command) will go through the
169 encrypted channel, and the connection to the real X server will be made
170 from the local machine. The user should not manually set DISPLAY. ForM--
171 warding of X11 connections can be configured on the command line or in
172 configuration files.
173
174 The DISPLAY value set by ssh will point to the server machine, but with a
175 display number greater than zero. This is normal, and happens because
176 ssh creates a ``proxy'' X server on the server machine for forwarding the
177 connections over the encrypted channel.
178
179 ssh will also automatically set up Xauthority data on the server machine.
180 For this purpose, it will generate a random authorization cookie, store
181 it in Xauthority on the server, and verify that any forwarded connections
182 carry this cookie and replace it by the real cookie when the connection
183 is opened. The real authentication cookie is never sent to the server
184 machine (and no cookies are sent in the plain).
185
186 If the user is using an authentication agent, the connection to the agent
187 is automatically forwarded to the remote side unless disabled on the comM--
188 mand line or in a configuration file.
189
190 Forwarding of arbitrary TCP/IP connections over the secure channel can be
191 specified either on the command line or in a configuration file. One
192 possible application of TCP/IP forwarding is a secure connection to an
193 electronic purse; another is going through firewalls.
194
195 Server authentication
196
197 ssh automatically maintains and checks a database containing identificaM--
198 tions for all hosts it has ever been used with. Host keys are stored in
199 $HOME/.ssh/known_hosts in the user's home directory. Additionally, the
200 file /etc/ssh/ssh_known_hosts is automatically checked for known hosts.
201 Any new hosts are automatically added to the user's file. If a host's
202 identification ever changes, ssh warns about this and disables password
203 authentication to prevent a trojan horse from getting the user's passM--
204 word. Another purpose of this mechanism is to prevent man-in-the-middle
205 attacks which could otherwise be used to circumvent the encryption. The
206 StrictHostKeyChecking option can be used to prevent logins to machines
207 whose host key is not known or has changed.
208
209 The options are as follows:
210
211 -a Disables forwarding of the authentication agent connection.
212
213 -A Enables forwarding of the authentication agent connection. This
214 can also be specified on a per-host basis in a configuration
215 file.
216
217 -b bind_address
218 Specify the interface to transmit from on machines with multiple
219 interfaces or aliased addresses.
220
221 -c blowfish|3des|des
222 Selects the cipher to use for encrypting the session. 3des is
223 used by default. It is believed to be secure. 3des (triple-des)
224 is an encrypt-decrypt-encrypt triple with three different keys.
225 blowfish is a fast block cipher, it appears very secure and is
226 much faster than 3des. des is only supported in the ssh client
227 for interoperability with legacy protocol 1 implementations that
228 do not support the 3des cipher. Its use is strongly discouraged
229 due to cryptographic weaknesses.
230
231 -c cipher_spec
232 Additionally, for protocol version 2 a comma-separated list of
233 ciphers can be specified in order of preference. See Ciphers for
234 more information.
235
236 -e ch|^ch|none
237 Sets the escape character for sessions with a pty (default: `~').
238 The escape character is only recognized at the beginning of a
239 line. The escape character followed by a dot (`.') closes the
240 connection, followed by control-Z suspends the connection, and
241 followed by itself sends the escape character once. Setting the
242 character to ``none'' disables any escapes and makes the session
243 fully transparent.
244
245 -f Requests ssh to go to background just before command execution.
246 This is useful if ssh is going to ask for passwords or
247 passphrases, but the user wants it in the background. This
248 implies -n. The recommended way to start X11 programs at a
249 remote site is with something like ssh -f host xterm.
250
251 -g Allows remote hosts to connect to local forwarded ports.
252
253 -i identity_file
254 Selects a file from which the identity (private key) for RSA or
255 DSA authentication is read. The default is $HOME/.ssh/identity
256 for protocol version 1, and $HOME/.ssh/id_rsa and
257 $HOME/.ssh/id_dsa for protocol version 2. Identity files may
258 also be specified on a per-host basis in the configuration file.
259 It is possible to have multiple -i options (and multiple identiM--
260 ties specified in configuration files).
261
262 -I smartcard_device
263 Specifies which smartcard device to use. The argument is the
264 device ssh should use to communicate with a smartcard used for
265 storing the user's private RSA key.
266
267 -k Disables forwarding of Kerberos tickets and AFS tokens. This may
268 also be specified on a per-host basis in the configuration file.
269
270 -l login_name
271 Specifies the user to log in as on the remote machine. This also
272 may be specified on a per-host basis in the configuration file.
273
274 -m mac_spec
275 Additionally, for protocol version 2 a comma-separated list of
276 MAC (message authentication code) algorithms can be specified in
277 order of preference. See the MACs keyword for more information.
278
279 -n Redirects stdin from /dev/null (actually, prevents reading from
280 stdin). This must be used when ssh is run in the background. A
281 common trick is to use this to run X11 programs on a remote
282 machine. For example, ssh -n shadows.cs.hut.fi emacs & will
283 start an emacs on shadows.cs.hut.fi, and the X11 connection will
284 be automatically forwarded over an encrypted channel. The ssh
285 program will be put in the background. (This does not work if
286 ssh needs to ask for a password or passphrase; see also the -f
287 option.)
288
289 -N Do not execute a remote command. This is useful for just forM--
290 warding ports (protocol version 2 only).
291
292 -o option
293 Can be used to give options in the format used in the configuraM--
294 tion file. This is useful for specifying options for which there
295 is no separate command-line flag.
296
297 -p port
298 Port to connect to on the remote host. This can be specified on
299 a per-host basis in the configuration file.
300
301 -P Use a non-privileged port for outgoing connections. This can be
302 used if a firewall does not permit connections from privileged
303 ports. Note that this option turns off RhostsAuthentication and
304 RhostsRSAAuthentication for older servers.
305
306 -q Quiet mode. Causes all warning and diagnostic messages to be
307 suppressed.
308
309 -s May be used to request invocation of a subsystem on the remote
310 system. Subsystems are a feature of the SSH2 protocol which
311 facilitate the use of SSH as a secure transport for other appliM--
312 cations (eg. sftp). The subsystem is specified as the remote comM--
313 mand.
314
315 -t Force pseudo-tty allocation. This can be used to execute arbiM--
316 trary screen-based programs on a remote machine, which can be
317 very useful, e.g., when implementing menu services. Multiple -t
318 options force tty allocation, even if ssh has no local tty.
319
320 -T Disable pseudo-tty allocation.
321
322 -v Verbose mode. Causes ssh to print debugging messages about its
323 progress. This is helpful in debugging connection, authenticaM--
324 tion, and configuration problems. Multiple -v options increases
325 the verbosity. Maximum is 3.
326
327 -x Disables X11 forwarding.
328
329 -X Enables X11 forwarding. This can also be specified on a per-host
330 basis in a configuration file.
331
332 -C Requests compression of all data (including stdin, stdout,
333 stderr, and data for forwarded X11 and TCP/IP connections). The
334 compression algorithm is the same used by gzip(1), and the
335 ``level'' can be controlled by the CompressionLevel option. ComM--
336 pression is desirable on modem lines and other slow connections,
337 but will only slow down things on fast networks. The default
338 value can be set on a host-by-host basis in the configuration
339 files; see the Compression option.
340
341 -F configfile
342 Specifies an alternative per-user configuration file. If a conM--
343 figuration file is given on the command line, the system-wide
344 configuration file (/etc/ssh/ssh_config) will be ignored. The
345 default for the per-user configuration file is $HOME/.ssh/config.
346
347 -L port:host:hostport
348 Specifies that the given port on the local (client) host is to be
349 forwarded to the given host and port on the remote side. This
350 works by allocating a socket to listen to port on the local side,
351 and whenever a connection is made to this port, the connection is
352 forwarded over the secure channel, and a connection is made to
353 host port hostport from the remote machine. Port forwardings can
354 also be specified in the configuration file. Only root can forM--
355 ward privileged ports. IPv6 addresses can be specified with an
356 alternative syntax: port/host/hostport
357
358 -R port:host:hostport
359 Specifies that the given port on the remote (server) host is to
360 be forwarded to the given host and port on the local side. This
361 works by allocating a socket to listen to port on the remote
362 side, and whenever a connection is made to this port, the connecM--
363 tion is forwarded over the secure channel, and a connection is
364 made to host port hostport from the local machine. Port forwardM--
365 ings can also be specified in the configuration file. Privileged
366 ports can be forwarded only when logging in as root on the remote
367 machine. IPv6 addresses can be specified with an alternative
368 syntax: port/host/hostport
369
370 -D port
371 Specifies a local ``dynamic'' application-level port forwarding.
372 This works by allocating a socket to listen to port on the local
373 side, and whenever a connection is made to this port, the connecM--
374 tion is forwarded over the secure channel, and the application
375 protocol is then used to determine where to connect to from the
376 remote machine. Currently the SOCKS4 protocol is supported, and
377 ssh will act as a SOCKS4 server. Only root can forward priviM--
378 leged ports. Dynamic port forwardings can also be specified in
379 the configuration file.
380
381 -1 Forces ssh to try protocol version 1 only.
382
383 -2 Forces ssh to try protocol version 2 only.
384
385 -4 Forces ssh to use IPv4 addresses only.
386
387 -6 Forces ssh to use IPv6 addresses only.
388
389CONFIGURATION FILES
390 ssh may additionally obtain configuration data from a per-user configuraM--
391 tion file and a system-wide configuration file. The file format and conM--
392 figuration options are described in ssh_config(5).
393
394ENVIRONMENT
395 ssh will normally set the following environment variables:
396
397 DISPLAY
398 The DISPLAY variable indicates the location of the X11 server.
399 It is automatically set by ssh to point to a value of the form
400 ``hostname:n'' where hostname indicates the host where the shell
401 runs, and n is an integer >= 1. ssh uses this special value to
402 forward X11 connections over the secure channel. The user should
403 normally not set DISPLAY explicitly, as that will render the X11
404 connection insecure (and will require the user to manually copy
405 any required authorization cookies).
406
407 HOME Set to the path of the user's home directory.
408
409 LOGNAME
410 Synonym for USER; set for compatibility with systems that use
411 this variable.
412
413 MAIL Set to the path of the user's mailbox.
414
415 PATH Set to the default PATH, as specified when compiling ssh.
416
417 SSH_ASKPASS
418 If ssh needs a passphrase, it will read the passphrase from the
419 current terminal if it was run from a terminal. If ssh does not
420 have a terminal associated with it but DISPLAY and SSH_ASKPASS
421 are set, it will execute the program specified by SSH_ASKPASS and
422 open an X11 window to read the passphrase. This is particularly
423 useful when calling ssh from a .Xsession or related script.
424 (Note that on some machines it may be necessary to redirect the
425 input from /dev/null to make this work.)
426
427 SSH_AUTH_SOCK
428 Identifies the path of a unix-domain socket used to communicate
429 with the agent.
430
431 SSH_CLIENT
432 Identifies the client end of the connection. The variable conM--
433 tains three space-separated values: client ip-address, client
434 port number, and server port number.
435
436 SSH_ORIGINAL_COMMAND
437 The variable contains the original command line if a forced comM--
438 mand is executed. It can be used to extract the original arguM--
439 ments.
440
441 SSH_TTY
442 This is set to the name of the tty (path to the device) associM--
443 ated with the current shell or command. If the current session
444 has no tty, this variable is not set.
445
446 TZ The timezone variable is set to indicate the present timezone if
447 it was set when the daemon was started (i.e., the daemon passes
448 the value on to new connections).
449
450 USER Set to the name of the user logging in.
451
452 Additionally, ssh reads $HOME/.ssh/environment, and adds lines of the
453 format ``VARNAME=value'' to the environment.
454
455FILES
456 $HOME/.ssh/known_hosts
457 Records host keys for all hosts the user has logged into that are
458 not in /etc/ssh/ssh_known_hosts. See sshd(8).
459
460 $HOME/.ssh/identity, $HOME/.ssh/id_dsa, $HOME/.ssh/id_rsa
461 Contains the authentication identity of the user. They are for
462 protocol 1 RSA, protocol 2 DSA, and protocol 2 RSA, respectively.
463 These files contain sensitive data and should be readable by the
464 user but not accessible by others (read/write/execute). Note
465 that ssh ignores a private key file if it is accessible by othM--
466 ers. It is possible to specify a passphrase when generating the
467 key; the passphrase will be used to encrypt the sensitive part of
468 this file using 3DES.
469
470 $HOME/.ssh/identity.pub, $HOME/.ssh/id_dsa.pub, $HOME/.ssh/id_rsa.pub
471 Contains the public key for authentication (public part of the
472 identity file in human-readable form). The contents of the
473 $HOME/.ssh/identity.pub file should be added to
474 $HOME/.ssh/authorized_keys on all machines where the user wishes
475 to log in using protocol version 1 RSA authentication. The conM--
476 tents of the $HOME/.ssh/id_dsa.pub and $HOME/.ssh/id_rsa.pub file
477 should be added to $HOME/.ssh/authorized_keys on all machines
478 where the user wishes to log in using protocol version 2 DSA/RSA
479 authentication. These files are not sensitive and can (but need
480 not) be readable by anyone. These files are never used automatiM--
481 cally and are not necessary; they are only provided for the conM--
482 venience of the user.
483
484 $HOME/.ssh/config
485 This is the per-user configuration file. The file format and
486 configuration options are described in ssh_config(5).
487
488 $HOME/.ssh/authorized_keys
489 Lists the public keys (RSA/DSA) that can be used for logging in
490 as this user. The format of this file is described in the
491 sshd(8) manual page. In the simplest form the format is the same
492 as the .pub identity files. This file is not highly sensitive,
493 but the recommended permissions are read/write for the user, and
494 not accessible by others.
495
496 /etc/ssh/ssh_known_hosts
497 Systemwide list of known host keys. This file should be prepared
498 by the system administrator to contain the public host keys of
499 all machines in the organization. This file should be world-
500 readable. This file contains public keys, one per line, in the
501 following format (fields separated by spaces): system name, pubM--
502 lic key and optional comment field. When different names are
503 used for the same machine, all such names should be listed, sepaM--
504 rated by commas. The format is described on the sshd(8) manual
505 page.
506
507 The canonical system name (as returned by name servers) is used
508 by sshd(8) to verify the client host when logging in; other names
509 are needed because ssh does not convert the user-supplied name to
510 a canonical name before checking the key, because someone with
511 access to the name servers would then be able to fool host
512 authentication.
513
514 /etc/ssh/ssh_config
515 Systemwide configuration file. The file format and configuration
516 options are described in ssh_config(5).
517
518 /etc/ssh/ssh_host_key, /etc/ssh/ssh_host_dsa_key,
519 /etc/ssh/ssh_host_rsa_key
520 These three files contain the private parts of the host keys and
521 are used for RhostsRSAAuthentication and HostbasedAuthentication.
522 If the protocol version 1 RhostsRSAAuthentication method is used,
523 ssh must be setuid root, since the host key is readable only by
524 root. For protocol version 2, ssh uses ssh-keysign(8) to access
525 the host keys for HostbasedAuthentication. This eliminates the
526 requirement that ssh be setuid root when that authentication
527 method is used. By default ssh is not setuid root.
528
529 $HOME/.rhosts
530 This file is used in .rhosts authentication to list the host/user
531 pairs that are permitted to log in. (Note that this file is also
532 used by rlogin and rsh, which makes using this file insecure.)
533 Each line of the file contains a host name (in the canonical form
534 returned by name servers), and then a user name on that host,
535 separated by a space. On some machines this file may need to be
536 world-readable if the user's home directory is on a NFS partiM--
537 tion, because sshd(8) reads it as root. Additionally, this file
538 must be owned by the user, and must not have write permissions
539 for anyone else. The recommended permission for most machines is
540 read/write for the user, and not accessible by others.
541
542 Note that by default sshd(8) will be installed so that it
543 requires successful RSA host authentication before permitting
544 .rhosts authentication. If the server machine does not have the
545 client's host key in /etc/ssh/ssh_known_hosts, it can be stored
546 in $HOME/.ssh/known_hosts. The easiest way to do this is to conM--
547 nect back to the client from the server machine using ssh; this
548 will automatically add the host key to $HOME/.ssh/known_hosts.
549
550 $HOME/.shosts
551 This file is used exactly the same way as .rhosts. The purpose
552 for having this file is to be able to use rhosts authentication
553 with ssh without permitting login with rlogin or rsh(1).
554
555 /etc/hosts.equiv
556 This file is used during .rhosts authentication. It contains
557 canonical hosts names, one per line (the full format is described
558 on the sshd(8) manual page). If the client host is found in this
559 file, login is automatically permitted provided client and server
560 user names are the same. Additionally, successful RSA host
561 authentication is normally required. This file should only be
562 writable by root.
563
564 /etc/shosts.equiv
565 This file is processed exactly as /etc/hosts.equiv. This file
566 may be useful to permit logins using ssh but not using
567 rsh/rlogin.
568
569 /etc/ssh/sshrc
570 Commands in this file are executed by ssh when the user logs in
571 just before the user's shell (or command) is started. See the
572 sshd(8) manual page for more information.
573
574 $HOME/.ssh/rc
575 Commands in this file are executed by ssh when the user logs in
576 just before the user's shell (or command) is started. See the
577 sshd(8) manual page for more information.
578
579 $HOME/.ssh/environment
580 Contains additional definitions for environment variables, see
581 section ENVIRONMENT above.
582
583DIAGNOSTICS
584 ssh exits with the exit status of the remote command or with 255 if an
585 error occurred.
586
587AUTHORS
588 OpenSSH is a derivative of the original and free ssh 1.2.12 release by
589 Tatu Ylonen. Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, Theo
590 de Raadt and Dug Song removed many bugs, re-added newer features and creM--
591 ated OpenSSH. Markus Friedl contributed the support for SSH protocol
592 versions 1.5 and 2.0.
593
594SEE ALSO
595 rsh(1), scp(1), sftp(1), ssh-add(1), ssh-agent(1), ssh-keygen(1),
596 telnet(1), ssh_config(5), ssh-keysign(8), sshd(8)
597
598 T. Ylonen, T. Kivinen, M. Saarinen, T. Rinne, and S. Lehtinen, SSH
599 Protocol Architecture, draft-ietf-secsh-architecture-12.txt, January
600 2002, work in progress material.
601
602BSD September 25, 1999 BSD