.\" (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 1.176 2003/09/29 11:40:51 jmc Exp $
+.\" $OpenBSD: ssh.1,v 1.193 2004/06/26 09:03:21 jmc Exp $
.Dd September 25, 1999
.Dt SSH 1
.Os
.Nd OpenSSH SSH client (remote login program)
.Sh SYNOPSIS
.Nm ssh
-.Op Fl 1246AaCfgkNnqsTtVvXx
+.Op Fl 1246AaCfgkMNnqsTtVvXxY
.Op Fl b Ar bind_address
.Op Fl c Ar cipher_spec
+.Bk -words
.Op Fl D Ar port
.Op Fl e Ar escape_char
.Op Fl F Ar configfile
.Op Fl i Ar identity_file
-.Bk -words
.Oo Fl L Xo
.Sm off
.Ar port :
.Sm on
.Xc
.Oc
+.Op Fl S Ar ctl
.Oo Ar user Ns @ Oc Ns Ar hostname
.Op Ar command
.Sh DESCRIPTION
supports hostbased or challenge response authentication.
.Pp
Protocol 2 provides additional mechanisms for confidentiality
-(the traffic is encrypted using 3DES, Blowfish, CAST128 or Arcfour)
-and integrity (hmac-md5, hmac-sha1).
+(the traffic is encrypted using AES, 3DES, Blowfish, CAST128 or Arcfour)
+and integrity (hmac-md5, hmac-sha1, hmac-ripemd160).
Note that protocol 1 lacks a strong mechanism for ensuring the
integrity of the connection.
.Ss Login session and remote execution
Send a BREAK to the remote system
(only useful for SSH protocol version 2 and if the peer supports it).
.It Cm ~C
-Open command line (only useful for adding port forwardings using the
+Open command line.
+Currently this allows the addition of port forwardings using the
.Fl L
and
.Fl R
-options).
+options (see below).
+It also allows the cancellation of existing remote port-forwardings
+using
+.Fl KR Ar hostport .
+Basic help is available, using the
+.Fl h
+option.
.It Cm ~R
Request rekeying of the connection
(only useful for SSH protocol version 2 and if the peer supports it).
configuration files; see the
.Cm Compression
option.
-.It Fl c Ar blowfish | 3des | des
-Selects the cipher to use for encrypting the session.
-.Ar 3des
-is used by default.
-It is believed to be secure.
+.It Fl c Ar cipher_spec
+Selects the cipher specification for encrypting the session.
+.Pp
+Protocol version 1 allows specification of a single cipher.
+The suported values are
+.Dq 3des ,
+.Dq blowfish
+and
+.Dq des .
.Ar 3des
(triple-des) is an encrypt-decrypt-encrypt triple with three different keys.
+It is believed to be secure.
.Ar blowfish
is a fast block cipher; it appears very secure and is much faster than
.Ar 3des .
.Ar 3des
cipher.
Its use is strongly discouraged due to cryptographic weaknesses.
-.It Fl c Ar cipher_spec
-Additionally, for protocol version 2 a comma-separated list of ciphers can
-be specified in order of preference.
-See
-.Cm Ciphers
-for more information.
+The default is
+.Dq 3des .
+.Pp
+For protocol version 2
+.Ar cipher_spec
+is a comma-separated list of ciphers
+listed in order of preference.
+The supported ciphers are
+.Dq 3des-cbc ,
+.Dq aes128-cbc ,
+.Dq aes192-cbc ,
+.Dq aes256-cbc ,
+.Dq aes128-ctr ,
+.Dq aes192-ctr ,
+.Dq aes256-ctr ,
+.Dq arcfour ,
+.Dq blowfish-cbc ,
+and
+.Dq cast128-cbc .
+The default is
+.Bd -literal
+ ``aes128-cbc,3des-cbc,blowfish-cbc,cast128-cbc,arcfour,
+ aes192-cbc,aes256-cbc''
+.Ed
.It Fl D Ar port
Specifies a local
.Dq dynamic
options (and multiple identities specified in
configuration files).
.It Fl k
-Disables forwarding of Kerberos tickets.
-This may also be specified on a per-host basis in the configuration file.
+Disables forwarding (delegation) of GSSAPI credentials to the server.
.It Fl L Xo
.Sm off
.Ar port : host : hostport
.It Fl l Ar login_name
Specifies the user to log in as on the remote machine.
This also may be specified on a per-host basis in the configuration file.
+.It Fl M
+Places the
+.Nm
+client into
+.Dq master
+mode for connection sharing.
+Refer to the description of
+.Cm ControlMaster
+in
+.Xr ssh_config 5
+for details.
.It Fl m Ar mac_spec
Additionally, for protocol version 2 a comma-separated list of MAC
(message authentication code) algorithms can
.It Compression
.It CompressionLevel
.It ConnectionAttempts
-.It ConnectionTimeout
+.It ConnectTimeout
+.It ControlMaster
+.It ControlPath
.It DynamicForward
-.It EnableSSHKeysign
.It EscapeChar
.It ForwardAgent
.It ForwardX11
+.It ForwardX11Trusted
.It GatewayPorts
.It GlobalKnownHostsFile
.It GSSAPIAuthentication
.It HostKeyAlias
.It HostName
.It IdentityFile
-.It KeepAlive
+.It IdentitiesOnly
.It LocalForward
.It LogLevel
.It MACs
.It RemoteForward
.It RhostsRSAAuthentication
.It RSAAuthentication
+.It SendEnv
+.It ServerAliveInterval
+.It ServerAliveCountMax
.It SmartcardDevice
.It StrictHostKeyChecking
+.It TCPKeepAlive
.It UsePrivilegedPort
.It User
.It UserKnownHostsFile
.Ar hostport .
.Xc
.Sm on
+.It Fl S Ar ctl
+Specifies the location of a control socket for connection sharing.
+Refer to the description of
+.Cm ControlPath
+and
+.Cm ControlMaster
+in
+.Xr ssh_config 5
+for details.
.It Fl s
May be used to request invocation of a subsystem on the remote system.
Subsystems are a feature of the SSH2 protocol which facilitate the use
An attacker may then be able to perform activities such as keystroke monitoring.
.It Fl x
Disables X11 forwarding.
+.It Fl Y
+Enables trusted X11 forwarding.
.El
.Sh CONFIGURATION FILES
.Nm
This is the per-user configuration file.
The file format and configuration options are described in
.Xr ssh_config 5 .
+Because of the potential for abuse, this file must have strict permissions:
+read/write for the user, and not accessible by others.
.It Pa $HOME/.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
andersk / openssh.git / blobdiff