.\" (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: ssh_config.5,v 1.89 2006/03/14 16:32:48 markus Exp $
-.Dd September 25, 1999
+.\" $OpenBSD: ssh_config.5,v 1.125 2009/12/29 18:03:32 jmc Exp $
+.Dd $Mdocdate$
.Dt SSH_CONFIG 5
.Os
.Sh NAME
.Nm ssh_config
.Nd OpenSSH SSH client configuration files
.Sh SYNOPSIS
-.Bl -tag -width Ds -compact
-.It Pa ~/.ssh/config
-.It Pa /etc/ssh/ssh_config
-.El
+.Nm ~/.ssh/config
+.Nm /etc/ssh/ssh_config
.Sh DESCRIPTION
.Xr ssh 1
obtains configuration data from the following sources in
.Cm Host
keyword) to be only for those hosts that match one of the patterns
given after the keyword.
+If more than one pattern is provided, they should be separated by whitespace.
A single
.Ql *
as a pattern can be used to provide global
.Dq cast128-cbc .
The default is:
.Bd -literal -offset 3n
-aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour128,
-arcfour256,arcfour,aes192-cbc,aes256-cbc,aes128-ctr,
-aes192-ctr,aes256-ctr
+aes128-ctr,aes192-ctr,aes256-ctr,arcfour256,arcfour128,
+aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,aes192-cbc,
+aes256-cbc,arcfour
.Ed
.It Cm ClearAllForwardings
Specifies that all local, remote, and dynamic port forwardings
to disable the escape
character entirely (making the connection transparent for binary
data).
+.It Cm ExitOnForwardFailure
+Specifies whether
+.Xr ssh 1
+should terminate the connection if it cannot set up all requested
+dynamic, tunnel, local, and remote port forwardings.
+The argument must be
+.Dq yes
+or
+.Dq no .
+The default is
+.Dq no .
.It Cm ForwardAgent
Specifies whether the connection to the authentication agent (if any)
will be forwarded to the remote machine.
be disclosed.
The default is
.Dq no .
-Note that hashing of names and addresses will not be retrospectively applied
-to existing known hosts files, but these may be manually hashed using
+Note that existing names and addresses in known hosts files
+will not be converted automatically,
+but may be manually hashed using
.Xr ssh-keygen 1 .
.It Cm HostbasedAuthentication
Specifies whether to try rhosts based authentication with public key
for protocol version 2.
Additionally, any identities represented by the authentication agent
will be used for authentication.
+.Pp
The file name may use the tilde
-syntax to refer to a user's home directory.
+syntax to refer to a user's home directory or one of the following
+escape characters:
+.Ql %d
+(local user's home directory),
+.Ql %u
+(local user name),
+.Ql %l
+(local host name),
+.Ql %h
+(remote host name) or
+.Ql %r
+(remote user name).
+.Pp
It is possible to have
multiple identity files specified in configuration files; all these
identities will be tried in sequence.
+.It Cm KbdInteractiveAuthentication
+Specifies whether to use keyboard-interactive authentication.
+The argument to this keyword must be
+.Dq yes
+or
+.Dq no .
+The default is
+.Dq yes .
.It Cm KbdInteractiveDevices
Specifies the list of methods to use in keyboard-interactive authentication.
Multiple method names must be comma-separated.
Specifies a command to execute on the local machine after successfully
connecting to the server.
The command string extends to the end of the line, and is executed with
-.Pa /bin/sh .
+the user's shell.
+The following escape character substitutions will be performed:
+.Ql %d
+(local user's home directory),
+.Ql %h
+(remote host name),
+.Ql %l
+(local host name),
+.Ql %n
+(host name as provided on the command line),
+.Ql %p
+(remote port),
+.Ql %r
+(remote user name) or
+.Ql %u
+(local user name).
+.Pp
+The command is run synchronously and does not have access to the
+session of the
+.Xr ssh 1
+that spawned it.
+It should not be used for interactive commands.
+.Pp
This directive is ignored unless
.Cm PermitLocalCommand
has been enabled.
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 NoHostAuthenticationForLocalhost
This option can be used if the home directory is shared across machines.
In this case localhost will refer to a different machine on each of
over another method (e.g.\&
.Cm password )
The default for this option is:
-.Dq hostbased,publickey,keyboard-interactive,password .
+.Do gssapi-with-mic ,
+hostbased,
+publickey,
+keyboard-interactive,
+password
+.Dc .
.It Cm Protocol
Specifies the protocol versions
.Xr ssh 1
and
.Sq 2 .
Multiple versions must be comma-separated.
-The default is
-.Dq 2,1 .
-This means that ssh
-tries version 2 and falls back to version 1
+When this option is set to
+.Dq 2,1
+.Nm ssh
+will try version 2 and fall back to version 1
if version 2 is not available.
+The default is
+.Sq 2 .
.It Cm ProxyCommand
Specifies the command to use to connect to the server.
The command
string extends to the end of the line, and is executed with
-.Pa /bin/sh .
+the user's shell.
In the command string,
.Ql %h
will be substituted by the host name to
.Ar host Ns / Ns Ar hostport .
Multiple forwardings may be specified, and additional
forwardings can be given on the command line.
-Only the superuser can forward privileged ports.
+Privileged ports can be forwarded only when
+logging in as root on the remote machine.
+.Pp
+If the
+.Ar port
+argument is
+.Ql 0 ,
+the listen port will be dynamically allocated on the server and reported
+to the client at run time.
.Pp
If the
.Ar bind_address
This option applies to protocol version 1 only and requires
.Xr ssh 1
to be setuid root.
+.It Cm RoutingDomain
+Set the routing domain number.
+The default routing domain is set by the system.
.It Cm RSAAuthentication
Specifies whether to try RSA authentication.
The argument to this keyword must be
To disable TCP keepalive messages, the value should be set to
.Dq no .
.It Cm Tunnel
-Request starting
+Request
.Xr tun 4
device forwarding between the client and the server.
-This option also allows requesting layer 2 (ethernet)
-instead of layer 3 (point-to-point) tunneling from the server.
The argument must be
.Dq yes ,
-.Dq point-to-point ,
-.Dq ethernet ,
+.Dq point-to-point
+(layer 3),
+.Dq ethernet
+(layer 2),
or
.Dq no .
+Specifying
+.Dq yes
+requests the default tunnel mode, which is
+.Dq point-to-point .
The default is
.Dq no .
.It Cm TunnelDevice
-Force a specified
+Specifies the
.Xr tun 4
-device on the client.
-Without this option, the next available device will be used.
+devices to open on the client
+.Pq Ar local_tun
+and the server
+.Pq Ar remote_tun .
+.Pp
+The argument must be
+.Sm off
+.Ar local_tun Op : Ar remote_tun .
+.Sm on
+The devices may be specified by numerical ID or the keyword
+.Dq any ,
+which uses the next available tunnel device.
+If
+.Ar remote_tun
+is not specified, it defaults to
+.Dq any .
+The default is
+.Dq any:any .
.It Cm UsePrivilegedPort
Specifies whether to use a privileged port for outgoing connections.
The argument must be
.Sx VERIFYING HOST KEYS
in
.Xr ssh 1 .
+.It Cm VisualHostKey
+If this flag is set to
+.Dq yes ,
+an ASCII art representation of the remote host key fingerprint is
+printed in addition to the hex fingerprint string at login and
+for unknown host keys.
+If this flag is set to
+.Dq no ,
+no fingerprint strings are printed at login and
+only the hex fingerprint string will be printed for unknown host keys.
+The default is
+.Dq no .
.It Cm XAuthLocation
Specifies the full pathname of the
.Xr xauth 1