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-.\" -*- nroff -*-
-.\"
-.\" Author: Tatu Ylonen <ylo@cs.hut.fi>
-.\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
-.\" All rights reserved
-.\"
-.\" As far as I am concerned, the code I have written for this software
-.\" can be used freely for any purpose. Any derived versions of this
-.\" software must be clearly marked as such, and if the derived work is
-.\" incompatible with the protocol description in the RFC file, it must be
-.\" called by a name other than "ssh" or "Secure Shell".
-.\"
-.\" Copyright (c) 1999,2000 Markus Friedl. All rights reserved.
-.\" Copyright (c) 1999 Aaron Campbell. All rights reserved.
-.\" Copyright (c) 1999 Theo de Raadt. All rights reserved.
-.\"
-.\" Redistribution and use in source and binary forms, with or without
-.\" modification, are permitted provided that the following conditions
-.\" are met:
-.\" 1. Redistributions of source code must retain the above copyright
-.\" notice, this list of conditions and the following disclaimer.
-.\" 2. Redistributions in binary form must reproduce the above copyright
-.\" notice, this list of conditions and the following disclaimer in the
-.\" documentation and/or other materials provided with the distribution.
-.\"
-.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
-.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
-.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
-.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
-.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
-.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
-.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-.\"
-.\" $OpenBSD: sshd.8,v 1.194 2003/01/31 21:54:40 jmc Exp $
-.Dd September 25, 1999
-.Dt SSHD 8
-.Os
-.Sh NAME
-.Nm sshd
-.Nd OpenSSH SSH daemon
-.Sh SYNOPSIS
-.Nm sshd
-.Bk -words
-.Op Fl deiqtD46
-.Op Fl b Ar bits
-.Op Fl f Ar config_file
-.Op Fl g Ar login_grace_time
-.Op Fl h Ar host_key_file
-.Op Fl k Ar key_gen_time
-.Op Fl o Ar option
-.Op Fl p Ar port
-.Op Fl u Ar len
-.Ek
-.Sh DESCRIPTION
-.Nm
-(SSH Daemon) is the daemon program for
-.Xr ssh 1 .
-Together these programs replace rlogin and rsh, and
-provide secure encrypted communications between two untrusted hosts
-over an insecure network.
-The programs are intended to be as easy to
-install and use as possible.
-.Pp
-.Nm
-is the daemon that listens for connections from clients.
-It is normally started at boot from
-.Pa /etc/rc .
-It forks a new
-daemon for each incoming connection.
-The forked daemons handle
-key exchange, encryption, authentication, command execution,
-and data exchange.
-This implementation of
-.Nm
-supports both SSH protocol version 1 and 2 simultaneously.
-.Nm
-works as follows:
-.Pp
-.Ss SSH protocol version 1
-.Pp
-Each host has a host-specific RSA key
-(normally 1024 bits) used to identify the host.
-Additionally, when
-the daemon starts, it generates a server RSA key (normally 768 bits).
-This key is normally regenerated every hour if it has been used, and
-is never stored on disk.
-.Pp
-Whenever a client connects, the daemon responds with its public
-host and server keys.
-The client compares the
-RSA host key against its own database to verify that it has not changed.
-The client then generates a 256 bit random number.
-It encrypts this
-random number using both the host key and the server key, and sends
-the encrypted number to the server.
-Both sides then use this
-random number as a session key which is used to encrypt all further
-communications in the session.
-The rest of the session is encrypted
-using a conventional cipher, currently Blowfish or 3DES, with 3DES
-being used by default.
-The client selects the encryption algorithm
-to use from those offered by the server.
-.Pp
-Next, the server and the client enter an authentication dialog.
-The client tries to authenticate itself using
-.Pa .rhosts
-authentication,
-.Pa .rhosts
-authentication combined with RSA host
-authentication, RSA challenge-response authentication, or password
-based authentication.
-.Pp
-Rhosts authentication is normally disabled
-because it is fundamentally insecure, but can be enabled in the server
-configuration file if desired.
-System security is not improved unless
-.Nm rshd ,
-.Nm rlogind ,
-and
-.Nm rexecd
-are disabled (thus completely disabling
-.Xr rlogin
-and
-.Xr rsh
-into the machine).
-.Pp
-.Ss SSH protocol version 2
-.Pp
-Version 2 works similarly:
-Each host has a host-specific key (RSA or DSA) used to identify the host.
-However, when the daemon starts, it does not generate a server key.
-Forward security is provided through a Diffie-Hellman key agreement.
-This key agreement results in a shared session key.
-.Pp
-The rest of the session is encrypted using a symmetric cipher, currently
-128 bit AES, Blowfish, 3DES, CAST128, Arcfour, 192 bit AES, or 256 bit AES.
-The client selects the encryption algorithm
-to use from those offered by the server.
-Additionally, session integrity is provided
-through a cryptographic message authentication code
-(hmac-sha1 or hmac-md5).
-.Pp
-Protocol version 2 provides a public key based
-user (PubkeyAuthentication) or
-client host (HostbasedAuthentication) authentication method,
-conventional password authentication and challenge response based methods.
-.Pp
-.Ss Command execution and data forwarding
-.Pp
-If the client successfully authenticates itself, a dialog for
-preparing the session is entered.
-At this time the client may request
-things like allocating a pseudo-tty, forwarding X11 connections,
-forwarding TCP/IP connections, or forwarding the authentication agent
-connection over the secure channel.
-.Pp
-Finally, the client either requests a shell or execution of a command.
-The sides then enter session mode.
-In this mode, either side may send
-data at any time, and such data is forwarded to/from the shell or
-command on the server side, and the user terminal in the client side.
-.Pp
-When the user program terminates and all forwarded X11 and other
-connections have been closed, the server sends command exit status to
-the client, and both sides exit.
-.Pp
-.Nm
-can be configured using command-line options or a configuration
-file.
-Command-line options override values specified in the
-configuration file.
-.Pp
-.Nm
-rereads its configuration file when it receives a hangup signal,
-.Dv SIGHUP ,
-by executing itself with the name it was started as, i.e.,
-.Pa /usr/sbin/sshd .
-.Pp
-The options are as follows:
-.Bl -tag -width Ds
-.It Fl b Ar bits
-Specifies the number of bits in the ephemeral protocol version 1
-server key (default 768).
-.It Fl d
-Debug mode.
-The server sends verbose debug output to the system
-log, and does not put itself in the background.
-The server also will not fork and will only process one connection.
-This option is only intended for debugging for the server.
-Multiple
-.Fl d
-options increase the debugging level.
-Maximum is 3.
-.It Fl e
-When this option is specified,
-.Nm
-will send the output to the standard error instead of the system log.
-.It Fl f Ar configuration_file
-Specifies the name of the configuration file.
-The default is
-.Pa /etc/ssh/sshd_config .
-.Nm
-refuses to start if there is no configuration file.
-.It Fl g Ar login_grace_time
-Gives the grace time for clients to authenticate themselves (default
-120 seconds).
-If the client fails to authenticate the user within
-this many seconds, the server disconnects and exits.
-A value of zero indicates no limit.
-.It Fl h Ar host_key_file
-Specifies a file from which a host key is read.
-This option must be given if
-.Nm
-is not run as root (as the normal
-host key files are normally not readable by anyone but root).
-The default is
-.Pa /etc/ssh/ssh_host_key
-for protocol version 1, and
-.Pa /etc/ssh/ssh_host_rsa_key
-and
-.Pa /etc/ssh/ssh_host_dsa_key
-for protocol version 2.
-It is possible to have multiple host key files for
-the different protocol versions and host key algorithms.
-.It Fl i
-Specifies that
-.Nm
-is being run from
-.Xr inetd 8 .
-.Nm
-is normally not run
-from inetd because it needs to generate the server key before it can
-respond to the client, and this may take tens of seconds.
-Clients would have to wait too long if the key was regenerated every time.
-However, with small key sizes (e.g., 512) using
-.Nm
-from inetd may
-be feasible.
-.It Fl k Ar key_gen_time
-Specifies how often the ephemeral protocol version 1 server key is
-regenerated (default 3600 seconds, or one hour).
-The motivation for regenerating the key fairly
-often is that the key is not stored anywhere, and after about an hour,
-it becomes impossible to recover the key for decrypting intercepted
-communications even if the machine is cracked into or physically
-seized.
-A value of zero indicates that the key will never be regenerated.
-.It Fl o Ar option
-Can be used to give options in the format used in the configuration file.
-This is useful for specifying options for which there is no separate
-command-line flag.
-.It Fl p Ar port
-Specifies the port on which the server listens for connections
-(default 22).
-Multiple port options are permitted.
-Ports specified in the configuration file are ignored when a
-command-line port is specified.
-.It Fl q
-Quiet mode.
-Nothing is sent to the system log.
-Normally the beginning,
-authentication, and termination of each connection is logged.
-.It Fl t
-Test mode.
-Only check the validity of the configuration file and sanity of the keys.
-This is useful for updating
-.Nm
-reliably as configuration options may change.
-.It Fl u Ar len
-This option is used to specify the size of the field
-in the
-.Li utmp
-structure that holds the remote host name.
-If the resolved host name is longer than
-.Ar len ,
-the dotted decimal value will be used instead.
-This allows hosts with very long host names that
-overflow this field to still be uniquely identified.
-Specifying
-.Fl u0
-indicates that only dotted decimal addresses
-should be put into the
-.Pa utmp
-file.
-.Fl u0
-may also be used to prevent
-.Nm
-from making DNS requests unless the authentication
-mechanism or configuration requires it.
-Authentication mechanisms that may require DNS include
-.Cm RhostsAuthentication ,
-.Cm RhostsRSAAuthentication ,
-.Cm HostbasedAuthentication
-and using a
-.Cm from="pattern-list"
-option in a key file.
-Configuration options that require DNS include using a
-USER@HOST pattern in
-.Cm AllowUsers
-or
-.Cm DenyUsers .
-.It Fl D
-When this option is specified
-.Nm
-will not detach and does not become a daemon.
-This allows easy monitoring of
-.Nm sshd .
-.It Fl 4
-Forces
-.Nm
-to use IPv4 addresses only.
-.It Fl 6
-Forces
-.Nm
-to use IPv6 addresses only.
-.El
-.Sh CONFIGURATION FILE
-.Nm
-reads configuration data from
-.Pa /etc/ssh/sshd_config
-(or the file specified with
-.Fl f
-on the command line).
-The file format and configuration options are described in
-.Xr sshd_config 5 .
-.Sh LOGIN PROCESS
-When a user successfully logs in,
-.Nm
-does the following:
-.Bl -enum -offset indent
-.It
-If the login is on a tty, and no command has been specified,
-prints last login time and
-.Pa /etc/motd
-(unless prevented in the configuration file or by
-.Pa $HOME/.hushlogin ;
-see the
-.Sx FILES
-section).
-.It
-If the login is on a tty, records login time.
-.It
-Checks
-.Pa /etc/nologin ;
-if it exists, prints contents and quits
-(unless root).
-.It
-Changes to run with normal user privileges.
-.It
-Sets up basic environment.
-.It
-Reads
-.Pa $HOME/.ssh/environment
-if it exists and users are allowed to change their environment.
-See the
-.Cm PermitUserEnvironment
-option in
-.Xr sshd_config 5 .
-.It
-Changes to user's home directory.
-.It
-If
-.Pa $HOME/.ssh/rc
-exists, runs it; else if
-.Pa /etc/ssh/sshrc
-exists, runs
-it; otherwise runs xauth.
-The
-.Dq rc
-files are given the X11
-authentication protocol and cookie in standard input.
-.It
-Runs user's shell or command.
-.El
-.Sh AUTHORIZED_KEYS FILE FORMAT
-.Pa $HOME/.ssh/authorized_keys
-is the default file that lists the public keys that are
-permitted for RSA authentication in protocol version 1
-and for public key authentication (PubkeyAuthentication)
-in protocol version 2.
-.Cm AuthorizedKeysFile
-may be used to specify an alternative file.
-.Pp
-Each line of the file contains one
-key (empty lines and lines starting with a
-.Ql #
-are ignored as
-comments).
-Each RSA public key consists of the following fields, separated by
-spaces: options, bits, exponent, modulus, comment.
-Each protocol version 2 public key consists of:
-options, keytype, base64 encoded key, comment.
-The options field
-is optional; its presence is determined by whether the line starts
-with a number or not (the options field never starts with a number).
-The bits, exponent, modulus and comment fields give the RSA key for
-protocol version 1; the
-comment field is not used for anything (but may be convenient for the
-user to identify the key).
-For protocol version 2 the keytype is
-.Dq ssh-dss
-or
-.Dq ssh-rsa .
-.Pp
-Note that lines in this file are usually several hundred bytes long
-(because of the size of the public key encoding).
-You don't want to type them in; instead, copy the
-.Pa identity.pub ,
-.Pa id_dsa.pub
-or the
-.Pa id_rsa.pub
-file and edit it.
-.Pp
-.Nm
-enforces a minimum RSA key modulus size for protocol 1
-and protocol 2 keys of 768 bits.
-.Pp
-The options (if present) consist of comma-separated option
-specifications.
-No spaces are permitted, except within double quotes.
-The following option specifications are supported (note
-that option keywords are case-insensitive):
-.Bl -tag -width Ds
-.It Cm from="pattern-list"
-Specifies that in addition to public key authentication, the canonical name
-of the remote host must be present in the comma-separated list of
-patterns
-.Pf ( Ql *
-and
-.Ql ?
-serve as wildcards).
-The list may also contain
-patterns negated by prefixing them with
-.Ql ! ;
-if the canonical host name matches a negated pattern, the key is not accepted.
-The purpose
-of this option is to optionally increase security: public key authentication
-by itself does not trust the network or name servers or anything (but
-the key); however, if somebody somehow steals the key, the key
-permits an intruder to log in from anywhere in the world.
-This additional option makes using a stolen key more difficult (name
-servers and/or routers would have to be compromised in addition to
-just the key).
-.It Cm command="command"
-Specifies that the command is executed whenever this key is used for
-authentication.
-The command supplied by the user (if any) is ignored.
-The command is run on a pty if the client requests a pty;
-otherwise it is run without a tty.
-If an 8-bit clean channel is required,
-one must not request a pty or should specify
-.Cm no-pty .
-A quote may be included in the command by quoting it with a backslash.
-This option might be useful
-to restrict certain public keys to perform just a specific operation.
-An example might be a key that permits remote backups but nothing else.
-Note that the client may specify TCP/IP and/or X11
-forwarding unless they are explicitly prohibited.
-Note that this option applies to shell, command or subsystem execution.
-.It Cm environment="NAME=value"
-Specifies that the string is to be added to the environment when
-logging in using this key.
-Environment variables set this way
-override other default environment values.
-Multiple options of this type are permitted.
-Environment processing is disabled by default and is
-controlled via the
-.Cm PermitUserEnvironment
-option.
-This option is automatically disabled if
-.Cm UseLogin
-is enabled.
-.It Cm no-port-forwarding
-Forbids TCP/IP forwarding when this key is used for authentication.
-Any port forward requests by the client will return an error.
-This might be used, e.g., in connection with the
-.Cm command
-option.
-.It Cm no-X11-forwarding
-Forbids X11 forwarding when this key is used for authentication.
-Any X11 forward requests by the client will return an error.
-.It Cm no-agent-forwarding
-Forbids authentication agent forwarding when this key is used for
-authentication.
-.It Cm no-pty
-Prevents tty allocation (a request to allocate a pty will fail).
-.It Cm permitopen="host:port"
-Limit local
-.Li ``ssh -L''
-port forwarding such that it may only connect to the specified host and
-port.
-IPv6 addresses can be specified with an alternative syntax:
-.Ar host/port .
-Multiple
-.Cm permitopen
-options may be applied separated by commas. No pattern matching is
-performed on the specified hostnames, they must be literal domains or
-addresses.
-.El
-.Ss Examples
-1024 33 12121.\|.\|.\|312314325 ylo@foo.bar
-.Pp
-from="*.niksula.hut.fi,!pc.niksula.hut.fi" 1024 35 23.\|.\|.\|2334 ylo@niksula
-.Pp
-command="dump /home",no-pty,no-port-forwarding 1024 33 23.\|.\|.\|2323 backup.hut.fi
-.Pp
-permitopen="10.2.1.55:80",permitopen="10.2.1.56:25" 1024 33 23.\|.\|.\|2323
-.Sh SSH_KNOWN_HOSTS FILE FORMAT
-The
-.Pa /etc/ssh/ssh_known_hosts
-and
-.Pa $HOME/.ssh/known_hosts
-files contain host public keys for all known hosts.
-The global file should
-be prepared by the administrator (optional), and the per-user file is
-maintained automatically: whenever the user connects from an unknown host
-its key is added to the per-user file.
-.Pp
-Each line in these files contains the following fields: hostnames,
-bits, exponent, modulus, comment.
-The fields are separated by spaces.
-.Pp
-Hostnames is a comma-separated list of patterns ('*' and '?' act as
-wildcards); each pattern in turn is matched against the canonical host
-name (when authenticating a client) or against the user-supplied
-name (when authenticating a server).
-A pattern may also be preceded by
-.Ql !
-to indicate negation: if the host name matches a negated
-pattern, it is not accepted (by that line) even if it matched another
-pattern on the line.
-.Pp
-Bits, exponent, and modulus are taken directly from the RSA host key; they
-can be obtained, e.g., from
-.Pa /etc/ssh/ssh_host_key.pub .
-The optional comment field continues to the end of the line, and is not used.
-.Pp
-Lines starting with
-.Ql #
-and empty lines are ignored as comments.
-.Pp
-When performing host authentication, authentication is accepted if any
-matching line has the proper key.
-It is thus permissible (but not
-recommended) to have several lines or different host keys for the same
-names.
-This will inevitably happen when short forms of host names
-from different domains are put in the file.
-It is possible
-that the files contain conflicting information; authentication is
-accepted if valid information can be found from either file.
-.Pp
-Note that the lines in these files are typically hundreds of characters
-long, and you definitely don't want to type in the host keys by hand.
-Rather, generate them by a script
-or by taking
-.Pa /etc/ssh/ssh_host_key.pub
-and adding the host names at the front.
-.Ss Examples
-.Bd -literal
-closenet,.\|.\|.\|,130.233.208.41 1024 37 159.\|.\|.93 closenet.hut.fi
-cvs.openbsd.org,199.185.137.3 ssh-rsa AAAA1234.....=
-.Ed
-.Sh FILES
-.Bl -tag -width Ds
-.It Pa /etc/ssh/sshd_config
-Contains configuration data for
-.Nm sshd .
-The file format and configuration options are described in
-.Xr sshd_config 5 .
-.It Pa /etc/ssh/ssh_host_key, /etc/ssh/ssh_host_dsa_key, /etc/ssh/ssh_host_rsa_key
-These three files contain the private parts of the host keys.
-These files should only be owned by root, readable only by root, and not
-accessible to others.
-Note that
-.Nm
-does not start if this file is group/world-accessible.
-.It Pa /etc/ssh/ssh_host_key.pub, /etc/ssh/ssh_host_dsa_key.pub, /etc/ssh/ssh_host_rsa_key.pub
-These three files contain the public parts of the host keys.
-These files should be world-readable but writable only by
-root.
-Their contents should match the respective private parts.
-These files are not
-really used for anything; they are provided for the convenience of
-the user so their contents can be copied to known hosts files.
-These files are created using
-.Xr ssh-keygen 1 .
-.It Pa /etc/moduli
-Contains Diffie-Hellman groups used for the "Diffie-Hellman Group Exchange".
-The file format is described in
-.Xr moduli 5 .
-.It Pa /var/empty
-.Xr chroot 2
-directory used by
-.Nm
-during privilege separation in the pre-authentication phase.
-The directory should not contain any files and must be owned by root
-and not group or world-writable.
-.It Pa /var/run/sshd.pid
-Contains the process ID of the
-.Nm
-listening for connections (if there are several daemons running
-concurrently for different ports, this contains the process ID of the one
-started last).
-The content of this file is not sensitive; it can be world-readable.
-.It Pa $HOME/.ssh/authorized_keys
-Lists the public keys (RSA or DSA) that can be used to log into the user's account.
-This file must be readable by root (which may on some machines imply
-it being world-readable if the user's home directory resides on an NFS
-volume).
-It is recommended that it not be accessible by others.
-The format of this file is described above.
-Users will place the contents of their
-.Pa identity.pub ,
-.Pa id_dsa.pub
-and/or
-.Pa id_rsa.pub
-files into this file, as described in
-.Xr ssh-keygen 1 .
-.It Pa "/etc/ssh/ssh_known_hosts" and "$HOME/.ssh/known_hosts"
-These files are consulted when using rhosts with RSA host
-authentication or protocol version 2 hostbased authentication
-to check the public key of the host.
-The key must be listed in one of these files to be accepted.
-The client uses the same files
-to verify that it is connecting to the correct remote host.
-These files should be writable only by root/the owner.
-.Pa /etc/ssh/ssh_known_hosts
-should be world-readable, and
-.Pa $HOME/.ssh/known_hosts
-can, but need not be, world-readable.
-.It Pa /etc/nologin
-If this file exists,
-.Nm
-refuses to let anyone except root log in.
-The contents of the file
-are displayed to anyone trying to log in, and non-root connections are
-refused.
-The file should be world-readable.
-.It Pa /etc/hosts.allow, /etc/hosts.deny
-Access controls that should be enforced by tcp-wrappers are defined here.
-Further details are described in
-.Xr hosts_access 5 .
-.It Pa $HOME/.rhosts
-This file contains host-username pairs, separated by a space, one per
-line.
-The given user on the corresponding host is permitted to log in
-without a password.
-The same file is used by rlogind and rshd.
-The file must
-be writable only by the user; it is recommended that it not be
-accessible by others.
-.Pp
-If is also possible to use netgroups in the file.
-Either host or user
-name may be of the form +@groupname to specify all hosts or all users
-in the group.
-.It Pa $HOME/.shosts
-For ssh,
-this file is exactly the same as for
-.Pa .rhosts .
-However, this file is
-not used by rlogin and rshd, so using this permits access using SSH only.
-.It Pa /etc/hosts.equiv
-This file is used during
-.Pa .rhosts
-authentication.
-In the simplest form, this file contains host names, one per line.
-Users on
-those hosts are permitted to log in without a password, provided they
-have the same user name on both machines.
-The host name may also be
-followed by a user name; such users are permitted to log in as
-.Em any
-user on this machine (except root).
-Additionally, the syntax
-.Dq +@group
-can be used to specify netgroups.
-Negated entries start with
-.Ql \&- .
-.Pp
-If the client host/user is successfully matched in this file, login is
-automatically permitted provided the client and server user names are the
-same.
-Additionally, successful RSA host authentication is normally required.
-This file must be writable only by root; it is recommended
-that it be world-readable.
-.Pp
-.Sy "Warning: It is almost never a good idea to use user names in"
-.Pa hosts.equiv .
-Beware that it really means that the named user(s) can log in as
-.Em anybody ,
-which includes bin, daemon, adm, and other accounts that own critical
-binaries and directories.
-Using a user name practically grants the user root access.
-The only valid use for user names that I can think
-of is in negative entries.
-.Pp
-Note that this warning also applies to rsh/rlogin.
-.It Pa /etc/shosts.equiv
-This is processed exactly as
-.Pa /etc/hosts.equiv .
-However, this file may be useful in environments that want to run both
-rsh/rlogin and ssh.
-.It Pa $HOME/.ssh/environment
-This file is read into the environment at login (if it exists).
-It can only contain empty lines, comment lines (that start with
-.Ql # ) ,
-and assignment lines of the form name=value.
-The file should be writable
-only by the user; it need not be readable by anyone else.
-Environment processing is disabled by default and is
-controlled via the
-.Cm PermitUserEnvironment
-option.
-.It Pa $HOME/.ssh/rc
-If this file exists, it is run with
-.Pa /bin/sh
-after reading the
-environment files but before starting the user's shell or command.
-It must not produce any output on stdout; stderr must be used
-instead.
-If X11 forwarding is in use, it will receive the "proto cookie" pair in
-its standard input (and
-.Ev DISPLAY
-in its environment).
-The script must call
-.Xr xauth 1
-because
-.Nm
-will not run xauth automatically to add X11 cookies.
-.Pp
-The primary purpose of this file is to run any initialization routines
-which may be needed before the user's home directory becomes
-accessible; AFS is a particular example of such an environment.
-.Pp
-This file will probably contain some initialization code followed by
-something similar to:
-.Bd -literal
-if read proto cookie && [ -n "$DISPLAY" ]; then
- if [ `echo $DISPLAY | cut -c1-10` = 'localhost:' ]; then
- # X11UseLocalhost=yes
- echo add unix:`echo $DISPLAY |
- cut -c11-` $proto $cookie
- else
- # X11UseLocalhost=no
- echo add $DISPLAY $proto $cookie
- fi | xauth -q -
-fi
-.Ed
-.Pp
-If this file does not exist,
-.Pa /etc/ssh/sshrc
-is run, and if that
-does not exist either, xauth is used to add the cookie.
-.Pp
-This file should be writable only by the user, and need not be
-readable by anyone else.
-.It Pa /etc/ssh/sshrc
-Like
-.Pa $HOME/.ssh/rc .
-This can be used to specify
-machine-specific login-time initializations globally.
-This file should be writable only by root, and should be world-readable.
-.El
-.Sh AUTHORS
-OpenSSH is a derivative of the original and free
-ssh 1.2.12 release by Tatu Ylonen.
-Aaron Campbell, Bob Beck, Markus Friedl, Niels Provos,
-Theo de Raadt and Dug Song
-removed many bugs, re-added newer features and
-created OpenSSH.
-Markus Friedl contributed the support for SSH
-protocol versions 1.5 and 2.0.
-Niels Provos and Markus Friedl contributed support
-for privilege separation.
-.Sh SEE ALSO
-.Xr scp 1 ,
-.Xr sftp 1 ,
-.Xr ssh 1 ,
-.Xr ssh-add 1 ,
-.Xr ssh-agent 1 ,
-.Xr ssh-keygen 1 ,
-.Xr login.conf 5 ,
-.Xr moduli 5 ,
-.Xr sshd_config 5 ,
-.Xr sftp-server 8
-.Rs
-.%A T. Ylonen
-.%A T. Kivinen
-.%A M. Saarinen
-.%A T. Rinne
-.%A S. Lehtinen
-.%T "SSH Protocol Architecture"
-.%N draft-ietf-secsh-architecture-12.txt
-.%D January 2002
-.%O work in progress material
-.Re
-.Rs
-.%A M. Friedl
-.%A N. Provos
-.%A W. A. Simpson
-.%T "Diffie-Hellman Group Exchange for the SSH Transport Layer Protocol"
-.%N draft-ietf-secsh-dh-group-exchange-02.txt
-.%D January 2002
-.%O work in progress material
-.Re