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1SSH(1) OpenBSD Reference 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 [-afgknqstvxACNTVX1246] [-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]
12 [-R 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 untrust-
18 ed hosts over an insecure network. X11 connections and arbitrary TCP/IP
19 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 de-
23 pending 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 com-
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 spoof-
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 chal-
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 authen-
73 tication.
74
75 The most convenient way to use RSA authentication may be with an authen-
76 tication agent. See ssh-agent(1) for more information.
77
78 If other authentication methods fail, ssh prompts the user for a pass-
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 serv-
100 er.
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 authentica-
106 tion.
107
108 Protocol 2 provides additional mechanisms for confidentiality (the traf-
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 ei-
116 ther 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 sta-
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 func-
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 charac-
140 ter can be changed in configuration files using the EscapeChar configura-
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 ~B Send a BREAK to the remote system (only useful for SSH protocol
157 version 2 and if the peer supports it)
158
159 ~C Open command line (only useful for adding port forwardings using
160 the -L and -R options)
161
162 ~R Request rekeying of the connection (only useful for SSH protocol
163 version 2 and if the peer supports it)
164
165 X11 and TCP forwarding
166
167 If the ForwardX11 variable is set to ``yes'' (or, see the description of
168 the -X and -x options described later) and the user is using X11 (the
169 DISPLAY environment variable is set), the connection to the X11 display
170 is automatically forwarded to the remote side in such a way that any X11
171 programs started from the shell (or command) will go through the encrypt-
172 ed channel, and the connection to the real X server will be made from the
173 local machine. The user should not manually set DISPLAY. Forwarding of
174 X11 connections can be configured on the command line or in configuration
175 files.
176
177 The DISPLAY value set by ssh will point to the server machine, but with a
178 display number greater than zero. This is normal, and happens because
179 ssh creates a ``proxy'' X server on the server machine for forwarding the
180 connections over the encrypted channel.
181
182 ssh will also automatically set up Xauthority data on the server machine.
183 For this purpose, it will generate a random authorization cookie, store
184 it in Xauthority on the server, and verify that any forwarded connections
185 carry this cookie and replace it by the real cookie when the connection
186 is opened. The real authentication cookie is never sent to the server
187 machine (and no cookies are sent in the plain).
188
189 If the ForwardAgent variable is set to ``yes'' (or, see the description
190 of the -A and -a options described later) and the user is using an au-
191 thentication agent, the connection to the agent is automatically forward-
192 ed to the remote side.
193
194 Forwarding of arbitrary TCP/IP connections over the secure channel can be
195 specified either on the command line or in a configuration file. One
196 possible application of TCP/IP forwarding is a secure connection to an
197 electronic purse; another is going through firewalls.
198
199 Server authentication
200
201 ssh automatically maintains and checks a database containing identifica-
202 tions for all hosts it has ever been used with. Host keys are stored in
203 $HOME/.ssh/known_hosts in the user's home directory. Additionally, the
204 file /etc/ssh/ssh_known_hosts is automatically checked for known hosts.
205 Any new hosts are automatically added to the user's file. If a host's
206 identification ever changes, ssh warns about this and disables password
207 authentication to prevent a trojan horse from getting the user's pass-
208 word. Another purpose of this mechanism is to prevent man-in-the-middle
209 attacks which could otherwise be used to circumvent the encryption. The
210 StrictHostKeyChecking option can be used to prevent logins to machines
211 whose host key is not known or has changed.
212
213 The options are as follows:
214
215 -a Disables forwarding of the authentication agent connection.
216
217 -A Enables forwarding of the authentication agent connection. This
218 can also be specified on a per-host basis in a configuration
219 file.
220
221 Agent forwarding should be enabled with caution. Users with the
222 ability to bypass file permissions on the remote host (for the
223 agent's Unix-domain socket) can access the local agent through
224 the forwarded connection. An attacker cannot obtain key material
225 from the agent, however they can perform operations on the keys
226 that enable them to authenticate using the identities loaded into
227 the agent.
228
229 -b bind_address
230 Specify the interface to transmit from on machines with multiple
231 interfaces or aliased addresses.
232
233 -c blowfish|3des|des
234 Selects the cipher to use for encrypting the session. 3des is
235 used by default. It is believed to be secure. 3des (triple-des)
236 is an encrypt-decrypt-encrypt triple with three different keys.
237 blowfish is a fast block cipher, it appears very secure and is
238 much faster than 3des. des is only supported in the ssh client
239 for interoperability with legacy protocol 1 implementations that
240 do not support the 3des cipher. Its use is strongly discouraged
241 due to cryptographic weaknesses.
242
243 -c cipher_spec
244 Additionally, for protocol version 2 a comma-separated list of
245 ciphers can be specified in order of preference. See Ciphers for
246 more information.
247
248 -e ch|^ch|none
249 Sets the escape character for sessions with a pty (default: `~').
250 The escape character is only recognized at the beginning of a
251 line. The escape character followed by a dot (`.') closes the
252 connection, followed by control-Z suspends the connection, and
253 followed by itself sends the escape character once. Setting the
254 character to ``none'' disables any escapes and makes the session
255 fully transparent.
256
257 -f Requests ssh to go to background just before command execution.
258 This is useful if ssh is going to ask for passwords or passphras-
259 es, but the user wants it in the background. This implies -n.
260 The recommended way to start X11 programs at a remote site is
261 with something like ssh -f host xterm.
262
263 -g Allows remote hosts to connect to local forwarded ports.
264
265 -i identity_file
266 Selects a file from which the identity (private key) for RSA or
267 DSA authentication is read. The default is $HOME/.ssh/identity
268 for protocol version 1, and $HOME/.ssh/id_rsa and
269 $HOME/.ssh/id_dsa for protocol version 2. Identity files may al-
270 so be specified on a per-host basis in the configuration file.
271 It is possible to have multiple -i options (and multiple identi-
272 ties specified in configuration files).
273
274 -I smartcard_device
275 Specifies which smartcard device to use. The argument is the de-
276 vice ssh should use to communicate with a smartcard used for
277 storing the user's private RSA key.
278
279 -k Disables forwarding of Kerberos tickets. This may also be speci-
280 fied on a per-host basis in the configuration file.
281
282 -l login_name
283 Specifies the user to log in as on the remote machine. This also
284 may be specified on a per-host basis in the configuration file.
285
286 -m mac_spec
287 Additionally, for protocol version 2 a comma-separated list of
288 MAC (message authentication code) algorithms can be specified in
289 order of preference. See the MACs keyword for more information.
290
291 -n Redirects stdin from /dev/null (actually, prevents reading from
292 stdin). This must be used when ssh is run in the background. A
293 common trick is to use this to run X11 programs on a remote ma-
294 chine. For example, ssh -n shadows.cs.hut.fi emacs & will start
295 an emacs on shadows.cs.hut.fi, and the X11 connection will be au-
296 tomatically forwarded over an encrypted channel. The ssh program
297 will be put in the background. (This does not work if ssh needs
298 to ask for a password or passphrase; see also the -f option.)
299
300 -N Do not execute a remote command. This is useful for just for-
301 warding ports (protocol version 2 only).
302
303 -o option
304 Can be used to give options in the format used in the configura-
305 tion file. This is useful for specifying options for which there
306 is no separate command-line flag.
307
308 -p port
309 Port to connect to on the remote host. This can be specified on
310 a per-host basis in the configuration file.
311
312 -q Quiet mode. Causes all warning and diagnostic messages to be
313 suppressed.
314
315 -s May be used to request invocation of a subsystem on the remote
316 system. Subsystems are a feature of the SSH2 protocol which fa-
317 cilitate the use of SSH as a secure transport for other applica-
318 tions (eg. sftp). The subsystem is specified as the remote com-
319 mand.
320
321 -t Force pseudo-tty allocation. This can be used to execute arbi-
322 trary screen-based programs on a remote machine, which can be
323 very useful, e.g., when implementing menu services. Multiple -t
324 options force tty allocation, even if ssh has no local tty.
325
326 -T Disable pseudo-tty allocation.
327
328 -v Verbose mode. Causes ssh to print debugging messages about its
329 progress. This is helpful in debugging connection, authentica-
330 tion, and configuration problems. Multiple -v options increase
331 the verbosity. The maximum is 3.
332
333 -V Display the version number and exit.
334
335 -x Disables X11 forwarding.
336
337 -X Enables X11 forwarding. This can also be specified on a per-host
338 basis in a configuration file.
339
340 X11 forwarding should be enabled with caution. Users with the
341 ability to bypass file permissions on the remote host (for the
342 user's X authorization database) can access the local X11 display
343 through the forwarded connection. An attacker may then be able
344 to perform activities such as keystroke monitoring.
345
346 -C Requests compression of all data (including stdin, stdout,
347 stderr, and data for forwarded X11 and TCP/IP connections). The
348 compression algorithm is the same used by gzip(1), and the
349 ``level'' can be controlled by the CompressionLevel option for
350 protocol version 1. Compression is desirable on modem lines and
351 other slow connections, but will only slow down things on fast
352 networks. The default value can be set on a host-by-host basis
353 in the configuration files; see the Compression option.
354
355 -F configfile
356 Specifies an alternative per-user configuration file. If a con-
357 figuration file is given on the command line, the system-wide
358 configuration file (/etc/ssh/ssh_config) will be ignored. The
359 default for the per-user configuration file is $HOME/.ssh/config.
360
361 -L port:host:hostport
362 Specifies that the given port on the local (client) host is to be
363 forwarded to the given host and port on the remote side. This
364 works by allocating a socket to listen to port on the local side,
365 and whenever a connection is made to this port, the connection is
366 forwarded over the secure channel, and a connection is made to
367 host port hostport from the remote machine. Port forwardings can
368 also be specified in the configuration file. Only root can for-
369 ward privileged ports. IPv6 addresses can be specified with an
370 alternative syntax: port/host/hostport
371
372 -R port:host:hostport
373 Specifies that the given port on the remote (server) host is to
374 be forwarded to the given host and port on the local side. This
375 works by allocating a socket to listen to port on the remote
376 side, and whenever a connection is made to this port, the connec-
377 tion is forwarded over the secure channel, and a connection is
378 made to host port hostport from the local machine. Port forward-
379 ings can also be specified in the configuration file. Privileged
380 ports can be forwarded only when logging in as root on the remote
381 machine. IPv6 addresses can be specified with an alternative
382 syntax: port/host/hostport
383
384 -D port
385 Specifies a local ``dynamic'' application-level port forwarding.
386 This works by allocating a socket to listen to port on the local
387 side, and whenever a connection is made to this port, the connec-
388 tion is forwarded over the secure channel, and the application
389 protocol is then used to determine where to connect to from the
390 remote machine. Currently the SOCKS4 and SOCKS5 protocols are
391 supported, and ssh will act as a SOCKS server. Only root can
392 forward privileged ports. Dynamic port forwardings can also be
393 specified in the configuration file.
394
395 -1 Forces ssh to try protocol version 1 only.
396
397 -2 Forces ssh to try protocol version 2 only.
398
399 -4 Forces ssh to use IPv4 addresses only.
400
401 -6 Forces ssh to use IPv6 addresses only.
402
403CONFIGURATION FILES
404 ssh may additionally obtain configuration data from a per-user configura-
405 tion file and a system-wide configuration file. The file format and con-
406 figuration options are described in ssh_config(5).
407
408ENVIRONMENT
409 ssh will normally set the following environment variables:
410
411 DISPLAY
412 The DISPLAY variable indicates the location of the X11 server.
413 It is automatically set by ssh to point to a value of the form
414 ``hostname:n'' where hostname indicates the host where the shell
415 runs, and n is an integer >= 1. ssh uses this special value to
416 forward X11 connections over the secure channel. The user should
417 normally not set DISPLAY explicitly, as that will render the X11
418 connection insecure (and will require the user to manually copy
419 any required authorization cookies).
420
421 HOME Set to the path of the user's home directory.
422
423 LOGNAME
424 Synonym for USER; set for compatibility with systems that use
425 this variable.
426
427 MAIL Set to the path of the user's mailbox.
428
429 PATH Set to the default PATH, as specified when compiling ssh.
430
431 SSH_ASKPASS
432 If ssh needs a passphrase, it will read the passphrase from the
433 current terminal if it was run from a terminal. If ssh does not
434 have a terminal associated with it but DISPLAY and SSH_ASKPASS
435 are set, it will execute the program specified by SSH_ASKPASS and
436 open an X11 window to read the passphrase. This is particularly
437 useful when calling ssh from a .Xsession or related script.
438 (Note that on some machines it may be necessary to redirect the
439 input from /dev/null to make this work.)
440
441 SSH_AUTH_SOCK
442 Identifies the path of a unix-domain socket used to communicate
443 with the agent.
444
445 SSH_CONNECTION
446 Identifies the client and server ends of the connection. The
447 variable contains four space-separated values: client ip-address,
448 client port number, server ip-address and server port number.
449
450 SSH_ORIGINAL_COMMAND
451 The variable contains the original command line if a forced com-
452 mand is executed. It can be used to extract the original argu-
453 ments.
454
455 SSH_TTY
456 This is set to the name of the tty (path to the device) associat-
457 ed with the current shell or command. If the current session has
458 no tty, this variable is not set.
459
460 TZ The timezone variable is set to indicate the present timezone if
461 it was set when the daemon was started (i.e., the daemon passes
462 the value on to new connections).
463
464 USER Set to the name of the user logging in.
465
466 Additionally, ssh reads $HOME/.ssh/environment, and adds lines of the
467 format ``VARNAME=value'' to the environment if the file exists and if
468 users are allowed to change their environment. See the
469 PermitUserEnvironment option in sshd_config(5).
470
471FILES
472 $HOME/.ssh/known_hosts
473 Records host keys for all hosts the user has logged into that are
474 not in /etc/ssh/ssh_known_hosts. See sshd(8).
475
476 $HOME/.ssh/identity, $HOME/.ssh/id_dsa, $HOME/.ssh/id_rsa
477 Contains the authentication identity of the user. They are for
478 protocol 1 RSA, protocol 2 DSA, and protocol 2 RSA, respectively.
479 These files contain sensitive data and should be readable by the
480 user but not accessible by others (read/write/execute). Note
481 that ssh ignores a private key file if it is accessible by oth-
482 ers. It is possible to specify a passphrase when generating the
483 key; the passphrase will be used to encrypt the sensitive part of
484 this file using 3DES.
485
486 $HOME/.ssh/identity.pub, $HOME/.ssh/id_dsa.pub, $HOME/.ssh/id_rsa.pub
487 Contains the public key for authentication (public part of the
488 identity file in human-readable form). The contents of the
489 $HOME/.ssh/identity.pub file should be added to
490 $HOME/.ssh/authorized_keys on all machines where the user wishes
491 to log in using protocol version 1 RSA authentication. The con-
492 tents of the $HOME/.ssh/id_dsa.pub and $HOME/.ssh/id_rsa.pub file
493 should be added to $HOME/.ssh/authorized_keys on all machines
494 where the user wishes to log in using protocol version 2 DSA/RSA
495 authentication. These files are not sensitive and can (but need
496 not) be readable by anyone. These files are never used automati-
497 cally and are not necessary; they are only provided for the con-
498 venience of the user.
499
500 $HOME/.ssh/config
501 This is the per-user configuration file. The file format and
502 configuration options are described in ssh_config(5).
503
504 $HOME/.ssh/authorized_keys
505 Lists the public keys (RSA/DSA) that can be used for logging in
506 as this user. The format of this file is described in the
507 sshd(8) manual page. In the simplest form the format is the same
508 as the .pub identity files. This file is not highly sensitive,
509 but the recommended permissions are read/write for the user, and
510 not accessible by others.
511
512 /etc/ssh/ssh_known_hosts
513 Systemwide list of known host keys. This file should be prepared
514 by the system administrator to contain the public host keys of
515 all machines in the organization. This file should be world-
516 readable. This file contains public keys, one per line, in the
517 following format (fields separated by spaces): system name, pub-
518 lic key and optional comment field. When different names are
519 used for the same machine, all such names should be listed, sepa-
520 rated by commas. The format is described on the sshd(8) manual
521 page.
522
523 The canonical system name (as returned by name servers) is used
524 by sshd(8) to verify the client host when logging in; other names
525 are needed because ssh does not convert the user-supplied name to
526 a canonical name before checking the key, because someone with
527 access to the name servers would then be able to fool host au-
528 thentication.
529
530 /etc/ssh/ssh_config
531 Systemwide configuration file. The file format and configuration
532 options are described in ssh_config(5).
533
534 /etc/ssh/ssh_host_key, /etc/ssh/ssh_host_dsa_key,
535 /etc/ssh/ssh_host_rsa_key
536 These three files contain the private parts of the host keys and
537 are used for RhostsRSAAuthentication and HostbasedAuthentication.
538 If the protocol version 1 RhostsRSAAuthentication method is used,
539 ssh must be setuid root, since the host key is readable only by
540 root. For protocol version 2, ssh uses ssh-keysign(8) to access
541 the host keys for HostbasedAuthentication. This eliminates the
542 requirement that ssh be setuid root when that authentication
543 method is used. By default ssh is not setuid root.
544
545 $HOME/.rhosts
546 This file is used in .rhosts authentication to list the host/user
547 pairs that are permitted to log in. (Note that this file is also
548 used by rlogin and rsh, which makes using this file insecure.)
549 Each line of the file contains a host name (in the canonical form
550 returned by name servers), and then a user name on that host,
551 separated by a space. On some machines this file may need to be
552 world-readable if the user's home directory is on a NFS parti-
553 tion, because sshd(8) reads it as root. Additionally, this file
554 must be owned by the user, and must not have write permissions
555 for anyone else. The recommended permission for most machines is
556 read/write for the user, and not accessible by others.
557
558 Note that by default sshd(8) will be installed so that it re-
559 quires successful RSA host authentication before permitting
560 .rhosts authentication. If the server machine does not have the
561 client's host key in /etc/ssh/ssh_known_hosts, it can be stored
562 in $HOME/.ssh/known_hosts. The easiest way to do this is to con-
563 nect back to the client from the server machine using ssh; this
564 will automatically add the host key to $HOME/.ssh/known_hosts.
565
566 $HOME/.shosts
567 This file is used exactly the same way as .rhosts. The purpose
568 for having this file is to be able to use rhosts authentication
569 with ssh without permitting login with rlogin or rsh(1).
570
571 /etc/hosts.equiv
572 This file is used during .rhosts authentication. It contains
573 canonical hosts names, one per line (the full format is described
574 on the sshd(8) manual page). If the client host is found in this
575 file, login is automatically permitted provided client and server
576 user names are the same. Additionally, successful RSA host au-
577 thentication is normally required. This file should only be
578 writable by root.
579
580 /etc/shosts.equiv
581 This file is processed exactly as /etc/hosts.equiv. This file
582 may be useful to permit logins using ssh but not using
583 rsh/rlogin.
584
585 /etc/ssh/sshrc
586 Commands in this file are executed by ssh when the user logs in
587 just before the user's shell (or command) is started. See the
588 sshd(8) manual page for more information.
589
590 $HOME/.ssh/rc
591 Commands in this file are executed by ssh when the user logs in
592 just before the user's shell (or command) is started. See the
593 sshd(8) manual page for more information.
594
595 $HOME/.ssh/environment
596 Contains additional definitions for environment variables, see
597 section ENVIRONMENT above.
598
599DIAGNOSTICS
600 ssh exits with the exit status of the remote command or with 255 if an
601 error occurred.
602
603SEE ALSO
604 rsh(1), scp(1), sftp(1), ssh-add(1), ssh-agent(1), ssh-keygen(1),
605 telnet(1), ssh_config(5), ssh-keysign(8), sshd(8)
606
607 T. Ylonen, T. Kivinen, M. Saarinen, T. Rinne, and S. Lehtinen, SSH
608 Protocol Architecture, draft-ietf-secsh-architecture-12.txt, January
609 2002, work in progress material.
610
611AUTHORS
612 OpenSSH is a derivative of the original and free ssh 1.2.12 release by
613 Tatu Ylonen. Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos, Theo
614 de Raadt and Dug Song removed many bugs, re-added newer features and
615 created OpenSSH. Markus Friedl contributed the support for SSH protocol
616 versions 1.5 and 2.0.
617
618OpenBSD 3.4 September 25, 1999 10