.\" -*- nroff -*-
.\"
-.\" sshd.8.in
-.\"
.\" Author: Tatu Ylonen <ylo@cs.hut.fi>
-.\"
.\" Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
.\" All rights reserved
.\"
-.\" Created: Sat Apr 22 21:55:14 1995 ylo
+.\" 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.
.\"
-.\" $Id$
+.\" 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 1.73 2000/11/22 15:38:30 provos Exp $
.Dd September 25, 1999
.Dt SSHD 8
.Os
(hmac-sha1 or hmac-md5).
.Pp
Protocol version 2 provides a public key based
-user authentication method (DSAAuthentication)
+user authentication method (PubkeyAuthentication)
and conventional password authentication.
.Pp
.Ss Command execution and data forwarding
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 -d options increases the debugging level.
+Maximum is 3.
.It Fl f Ar configuration_file
Specifies the name of the configuration file.
The default is
.It Fl Q
Do not print an error message if RSA support is missing.
.It Fl V Ar client_protocol_id
-SSH2 compatibility mode.
+SSH-2 compatibility mode.
When this option is specified
.Nm
assumes the client has sent the supplied version string
and skips the
Protocol Version Identification Exchange.
+This option is not intended to be called directly.
.It Fl 4
Forces
.Nm
Only group names are valid; a numerical group ID isn't recognized.
By default login is allowed regardless of the primary group.
.Pp
+.It Cm AllowTcpForwarding
+Specifies whether TCP forwarding is permitted.
+The default is
+.Dq yes .
+Note that disabling TCP forwarding does not improve security unless
+users are also denied shell access, as they can always install their
+own forwarders.
+.Pp
.It Cm AllowUsers
This keyword can be followed by a number of user names, separated
by spaces.
can be used as wildcards in the patterns.
Only user names are valid; a numerical user ID isn't recognized.
By default login is allowed regardless of the user name.
-.It Cm DSAAuthentication
-Specifies whether DSA authentication is allowed.
+.It Cm PubkeyAuthentication
+Specifies whether public key authentication is allowed.
The default is
.Dq yes .
Note that this option applies to protocol version 2 only.
.Dq no .
The default is
.Dq no .
-.It Cm HostDSAKey
-Specifies the file containing the private DSA host key (default
-.Pa /etc/ssh_host_dsa_key )
-used by SSH protocol 2.0.
-Note that
-.Nm
-disables protocol 2.0 if this file is group/world-accessible.
.It Cm HostKey
-Specifies the file containing the private RSA host key (default
+Specifies the file containing the private host keys (default
.Pa /etc/ssh_host_key )
-used by SSH protocols 1.3 and 1.5.
+used by SSH protocol versions 1 and 2.
Note that
.Nm
-disables protocols 1.3 and 1.5 if this file is group/world-accessible.
+if this file is group/world-accessible.
+It is possible to have multiple host key files.
+.Dq rsa1
+keys are used for version 1 and
+.Dq dsa
+or
+.Dq rsa
+are used for version 2 of the SSH protocol.
.It Cm IgnoreRhosts
Specifies that
.Pa .rhosts
This can be in the form of a Kerberos ticket, or if
.Cm PasswordAuthentication
is yes, the password provided by the user will be validated through
-the Kerberos KDC. To use this option, the server needs a
+the Kerberos KDC.
+To use this option, the server needs a
Kerberos servtab which allows the verification of the KDC's identity.
Default is
.Dq yes .
If set then if password authentication through Kerberos fails then
the password will be validated via any additional local mechanism
such as
-.Pa /etc/passwd
-or SecurID.
+.Pa /etc/passwd .
Default is
.Dq yes .
.It Cm KerberosTgtPassing
Alternatively, random early drop can be enabled by specifying
the three colon separated values
.Dq start:rate:full
-(e.g. "10:30:60").
+(e.g., "10:30:60").
.Nm
will refuse connection attempts with a probabillity of
.Dq rate/100
The default is
.Dq yes .
.It Cm Subsystem
-Configures an external subsystem (e.g. file transfer daemon).
-Arguments should be a subsystem name and a command to execute upon subsystem request.
+Configures an external subsystem (e.g., file transfer daemon).
+Arguments should be a subsystem name and a command to execute upon subsystem
+request.
+The command
+.Xr sftp-server 8
+implements the
+.Dq sftp
+file transfer subsystem.
By default no subsystems are defined.
Note that this option applies to protocol version 2 only.
.It Cm SyslogFacility
the user so its contents can be copied to known hosts files.
These two files are created using
.Xr ssh-keygen 1 .
+.It Pa /etc/primes
+Contains Diffie-Hellman groups used for the "Diffie-Hellman Group Exchange".
.It Pa /var/run/sshd.pid
Contains the process ID of the
.Nm
machine-specific login-time initializations globally.
This file should be writable only by root, and should be world-readable.
.El
-.Sh AUTHOR
+.Sh AUTHORS
OpenSSH
is a derivative of the original (free) ssh 1.2.12 release by Tatu Ylonen,
but with bugs removed and newer features re-added.
This version of OpenSSH
.Bl -bullet
.It
-has all components of a restrictive nature (i.e., patents)
+has all components of a restrictive nature (i.e., patents, see
+.Xr crypto 3 )
directly removed from the source code; any licensed or patented components
are chosen from
external libraries.
The support for SSH protocol 2 was written by Markus Friedl.
.Sh SEE ALSO
.Xr scp 1 ,
+.Xr sftp-server 8 ,
.Xr ssh 1 ,
.Xr ssh-add 1 ,
.Xr ssh-agent 1 ,
.Xr ssh-keygen 1 ,
+.Xr crypto 3 ,
.Xr rlogin 1 ,
.Xr rsh 1
andersk / openssh.git / blobdiff