.\" (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 1.88 2006/03/13 10:14:29 dtucker Exp $
-.Dd September 25, 1999
+.\" $OpenBSD: ssh_config.5,v 1.126 2010/01/09 23:04:13 dtucker 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
.Cm ServerAliveCountMax
is left at the default, if the server becomes unresponsive,
ssh will disconnect after approximately 45 seconds.
+This option applies to protocol version 2 only.
.It Cm ServerAliveInterval
Sets a timeout interval in seconds after which if no data has been received
from the server,
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
andersk / openssh.git / blobdiff