.\" (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_config.5,v 1.70 2006/08/21 08:14:01 dtucker Exp $
-.Dd September 25, 1999
+.\" $OpenBSD: sshd_config.5,v 1.84 2008/03/25 11:58:02 djm Exp $
+.Dd $Mdocdate: March 27 2008 $
.Dt SSHD_CONFIG 5
.Os
.Sh NAME
.Nm sshd_config
.Nd OpenSSH SSH daemon configuration file
.Sh SYNOPSIS
-.Bl -tag -width Ds -compact
-.It Pa /etc/ssh/sshd_config
-.El
+.Nm /etc/ssh/sshd_config
.Sh DESCRIPTION
.Xr sshd 8
reads configuration data from
The default is
.Dq .ssh/authorized_keys .
.It Cm Banner
-In some jurisdictions, sending a warning message before authentication
-may be relevant for getting legal protection.
The contents of the specified file are sent to the remote user before
authentication is allowed.
+If the argument is
+.Dq none
+then no banner is displayed.
This option is only available for protocol version 2.
By default, no banner is displayed.
.It Cm ChallengeResponseAuthentication
are supported.
The default is
.Dq yes .
+.It Cm ChrootDirectory
+Specifies a path to
+.Xr chroot 2
+to after authentication.
+This path, and all its components, must be root-owned directories that are
+not writable by any other user or group.
+.Pp
+The path may contain the following tokens that are expanded at runtime once
+the connecting user has been authenticated: %% is replaced by a literal '%',
+%h is replaced by the home directory of the user being authenticated, and
+%u is replaced by the username of that user.
+.Pp
+The
+.Cm ChrootDirectory
+must contain the necessary files and directories to support the
+users' session.
+For an interactive session this requires at least a shell, typically
+.Xr sh 1 ,
+and basic
+.Pa /dev
+nodes such as
+.Xr null 4 ,
+.Xr zero 4 ,
+.Xr stdin 4 ,
+.Xr stdout 4 ,
+.Xr stderr 4 ,
+.Xr arandom 4
+and
+.Xr tty 4
+devices.
+For file transfer sessions using
+.Dq sftp ,
+no additional configuration of the environment is necessary if the
+in-process sftp server is used (see
+.Cm Subsystem
+for details).
+.Pp
+The default is not to
+.Xr chroot 2 .
.It Cm Ciphers
Specifies the ciphers allowed for protocol version 2.
Multiple ciphers must be comma-separated.
.It Cm ForceCommand
Forces the execution of the command specified by
.Cm ForceCommand ,
-ignoring any command supplied by the client.
+ignoring any command supplied by the client and
+.Pa ~/.ssh/rc
+if present.
The command is invoked by using the user's login shell with the -c option.
This applies to shell, command, or subsystem execution.
It is most useful inside a
The command originally supplied by the client is available in the
.Ev SSH_ORIGINAL_COMMAND
environment variable.
+Specifying a command of
+.Dq internal-sftp
+will force the use of an in-process sftp server that requires no support
+files when used with
+.Cm ChrootDirectory .
.It Cm GatewayPorts
Specifies whether remote hosts are allowed to connect to ports
forwarded for the client.
The default is
.Dq yes .
Note that this option applies to protocol version 2 only.
+.It Cm GSSAPIDelegateCredentials
+Specifies whether delegated credentials are stored in the user's environment.
+The default is
+.Dq yes .
.It Cm GSSAPIKeyExchange
Specifies whether key exchange based on GSSAPI is allowed. GSSAPI key exchange
doesn't rely on ssh keys to verify host identity.
for data integrity protection.
Multiple algorithms must be comma-separated.
The default is:
-.Dq hmac-md5,hmac-sha1,hmac-ripemd160,hmac-sha1-96,hmac-md5-96 .
+.Bd -literal -offset indent
+hmac-md5,hmac-sha1,umac-64@openssh.com,
+hmac-ripemd160,hmac-sha1-96,hmac-md5-96
+.Ed
.It Cm Match
Introduces a conditional block.
If all of the criteria on the
keyword.
Available keywords are
.Cm AllowTcpForwarding ,
+.Cm Banner ,
.Cm ForceCommand ,
.Cm GatewayPorts ,
+.Cm GSSApiAuthentication ,
+.Cm KbdInteractiveAuthentication ,
+.Cm KerberosAuthentication ,
+.Cm PasswordAuthentication ,
.Cm PermitOpen ,
+.Cm PermitRootLogin ,
+.Cm RhostsRSAAuthentication ,
+.Cm RSAAuthentication ,
.Cm X11DisplayOffset ,
.Cm X11Forwarding ,
and
Configures an external subsystem (e.g. file transfer daemon).
Arguments should be a subsystem name and a command (with optional arguments)
to execute upon subsystem request.
+.Pp
The command
.Xr sftp-server 8
implements the
.Dq sftp
file transfer subsystem.
+.Pp
+Alternately the name
+.Dq internal-sftp
+implements an in-process
+.Dq sftp
+server.
+This may simplify configurations using
+.Cm ChrootDirectory
+to force a different filesystem root on clients.
+.Pp
By default no subsystems are defined.
Note that this option applies to protocol version 2 only.
.It Cm SyslogFacility
andersk / gssapi-openssh.git / blobdiff