.\" (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.1,v 1.253 2006/01/30 13:37:49 jmc Exp $
-.Dd September 25, 1999
+.\" $OpenBSD: ssh.1,v 1.273 2008/02/11 07:58:28 jmc Exp $
+.Dd $Mdocdate: March 26 2008 $
.Dt SSH 1
.Os
.Sh NAME
.Nd OpenSSH SSH client (remote login program)
.Sh SYNOPSIS
.Nm ssh
-.Op Fl 1246AaCfgkMNnqsTtVvXxY
+.Op Fl 1246AaCfgKkMNnqsTtVvXxY
.Op Fl b Ar bind_address
.Op Fl c Ar cipher_spec
.Oo Fl D\ \&
.Oc
.Op Fl S Ar ctl_path
.Bk -words
-.Op Fl w Ar tunnel : Ns Ar tunnel
+.Oo Fl w Ar local_tun Ns
+.Op : Ns Ar remote_tun Oc
.Oo Ar user Ns @ Oc Ns Ar hostname
.Op Ar command
.Ek
.Fl i
options (and multiple identities specified in
configuration files).
+.It Fl K
+Enables GSSAPI-based authentication and forwarding (delegation) of GSSAPI
+credentials to the server.
.It Fl k
Disables forwarding (delegation) of GSSAPI credentials to the server.
.It Fl L Xo
.It ControlPath
.It DynamicForward
.It EscapeChar
+.It ExitOnForwardFailure
.It ForwardAgent
.It ForwardX11
.It ForwardX11Trusted
per-host basis in the configuration file.
.It Fl q
Quiet mode.
-Causes all warning and diagnostic messages to be suppressed.
+Causes most warning and diagnostic messages to be suppressed.
.It Fl R Xo
.Sm off
.Oo Ar bind_address : Oc
Force pseudo-tty allocation.
This can be used to execute arbitrary
screen-based programs on a remote machine, which can be very useful,
-e.g., when implementing menu services.
+e.g. when implementing menu services.
Multiple
.Fl t
options force tty allocation, even if
.Fl v
options increase the verbosity.
The maximum is 3.
-.It Fl w Ar tunnel : Ns Ar tunnel
-Requests a
+.It Fl w Xo
+.Ar local_tun Ns Op : Ns Ar remote_tun
+.Xc
+Requests
+tunnel
+device forwarding with the specified
.Xr tun 4
-device on the client
-(first
-.Ar tunnel
-arg)
-and server
-(second
-.Ar tunnel
-arg).
+devices between the client
+.Pq Ar local_tun
+and the server
+.Pq Ar remote_tun .
+.Pp
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 .
See also the
.Cm Tunnel
-directive in
+and
+.Cm TunnelDevice
+directives in
.Xr ssh_config 5 .
+If the
+.Cm Tunnel
+directive is unset, it is set to the default tunnel mode, which is
+.Dq point-to-point .
.It Fl X
Enables X11 forwarding.
This can also be specified on a per-host basis in a configuration file.
but protocol 2 is preferred since
it provides additional mechanisms for confidentiality
(the traffic is encrypted using AES, 3DES, Blowfish, CAST128, or Arcfour)
-and integrity (hmac-md5, hmac-sha1, hmac-ripemd160).
+and integrity (hmac-md5, hmac-sha1, umac-64, hmac-ripemd160).
Protocol 1 lacks a strong mechanism for ensuring the
integrity of the connection.
.Pp
The methods available for authentication are:
+GSSAPI-based authentication,
host-based authentication,
public key authentication,
challenge-response authentication,
options (see above).
It also allows the cancellation of existing remote port-forwardings
using
-.Fl KR Ar hostport .
+.Sm off
+.Fl KR Oo Ar bind_address : Oc Ar port .
+.Sm on
.Ic !\& Ns Ar command
allows the user to execute a local command if the
.Ic PermitLocalCommand
The SSHFP resource records should first be added to the zonefile for
host.example.com:
.Bd -literal -offset indent
-$ ssh-keygen -f /etc/ssh/ssh_host_rsa_key.pub -r host.example.com.
-$ ssh-keygen -f /etc/ssh/ssh_host_dsa_key.pub -r host.example.com.
+$ ssh-keygen -r host.example.com.
.Ed
.Pp
The output lines will have to be added to the zonefile.
and at what level (layer 2 or 3 traffic).
.Pp
The following example would connect client network 10.0.50.0/24
-with remote network 10.0.99.0/24, provided that the SSH server
-running on the gateway to the remote network,
-at 192.168.1.15, allows it:
+with remote network 10.0.99.0/24 using a point-to-point connection
+from 10.1.1.1 to 10.1.1.2,
+provided that the SSH server running on the gateway to the remote network,
+at 192.168.1.15, allows it.
+.Pp
+On the client:
.Bd -literal -offset indent
# ssh -f -w 0:1 192.168.1.15 true
-# ifconfig tun0 10.0.50.1 10.0.99.1 netmask 255.255.255.252
+# ifconfig tun0 10.1.1.1 10.1.1.2 netmask 255.255.255.252
+# route add 10.0.99.0/24 10.1.1.2
+.Ed
+.Pp
+On the server:
+.Bd -literal -offset indent
+# ifconfig tun1 10.1.1.2 10.1.1.1 netmask 255.255.255.252
+# route add 10.0.50.0/24 10.1.1.1
.Ed
.Pp
Client access may be more finely tuned via the
file (see below) and the
.Cm PermitRootLogin
server option.
-The following entry would permit connections on the first
+The following entry would permit connections on
.Xr tun 4
-device from user
+device 1 from user
.Dq jane
-and on the second device from user
+and on tun device 2 from user
.Dq john ,
if
.Cm PermitRootLogin
.Dq forced-commands-only :
.Bd -literal -offset 2n
tunnel="1",command="sh /etc/netstart tun1" ssh-rsa ... jane
-tunnel="2",command="sh /etc/netstart tun1" ssh-rsa ... john
+tunnel="2",command="sh /etc/netstart tun2" ssh-rsa ... john
.Ed
.Pp
-Since a SSH-based setup entails a fair amount of overhead,
+Since an SSH-based setup entails a fair amount of overhead,
it may be more suited to temporary setups,
such as for wireless VPNs.
More permanent VPNs are better provided by tools such as
this variable is not set.
.It Ev TZ
This variable is set to indicate the present time zone if it
-was set when the daemon was started (i.e., the daemon passes the value
+was set when the daemon was started (i.e. the daemon passes the value
on to new connections).
.It Ev USER
Set to the name of the user logging in.
but allows host-based authentication without permitting login with
rlogin/rsh.
.Pp
+.It ~/.ssh/
+This directory is the default location for all user-specific configuration
+and authentication information.
+There is no general requirement to keep the entire contents of this directory
+secret, but the recommended permissions are read/write/execute for the user,
+and not accessible by others.
+.Pp
.It ~/.ssh/authorized_keys
Lists the public keys (RSA/DSA) that can be used for logging in as this user.
The format of this file is described in the
.Xr ssh-keysign 8 ,
.Xr sshd 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
+.%R RFC 4250
+.%T "The Secure Shell (SSH) Protocol Assigned Numbers"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4251
+.%T "The Secure Shell (SSH) Protocol Architecture"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4252
+.%T "The Secure Shell (SSH) Authentication Protocol"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4253
+.%T "The Secure Shell (SSH) Transport Layer Protocol"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4254
+.%T "The Secure Shell (SSH) Connection Protocol"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4255
+.%T "Using DNS to Securely Publish Secure Shell (SSH) Key Fingerprints"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4256
+.%T "Generic Message Exchange Authentication for the Secure Shell Protocol (SSH)"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4335
+.%T "The Secure Shell (SSH) Session Channel Break Extension"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4344
+.%T "The Secure Shell (SSH) Transport Layer Encryption Modes"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4345
+.%T "Improved Arcfour Modes for the Secure Shell (SSH) Transport Layer Protocol"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4419
+.%T "Diffie-Hellman Group Exchange for the Secure Shell (SSH) Transport Layer Protocol"
+.%D 2006
+.Re
+.Rs
+.%R RFC 4716
+.%T "The Secure Shell (SSH) Public Key File Format"
+.%D 2006
.Re
.Sh AUTHORS
OpenSSH is a derivative of the original and free
andersk / gssapi-openssh.git / blobdiff