SSH 命令行参数详解【英】

ssh connects and logs into the specified hostname (with optional user name).  The user must prove his/her
identity to the remote machine using one of several methods depending on the protocol version used (see
below).

If command is specified, it is executed on the remote host instead of a login shell.

-1      Forces ssh to try protocol version 1 only.

-2      Forces ssh to try protocol version 2 only.

-4      Forces ssh to use IPv4 addresses only.

-6      Forces ssh to use IPv6 addresses only.

-A      Enables forwarding of the authentication agent connection.  This can also be specified on a per-
        host basis in a configuration file.

        Agent forwarding should be enabled with caution.  Users with the ability to bypass file permissions
        on the remote host (for the agent's UNIX-domain socket) can access the local agent through the
        forwarded connection.  An attacker cannot obtain key material from the agent, however they can
        perform operations on the keys that enable them to authenticate using the identities loaded into
        the agent.

-a      Disables forwarding of the authentication agent connection.

-b bind_address
        Use bind_address on the local machine as the source address of the connection.  Only useful on
        systems with more than one address.

-C      Requests compression of all data (including stdin, stdout, stderr, and data for forwarded X11 and
        TCP connections).  The compression algorithm is the same used by gzip(1), and the “level” can be
        controlled by the CompressionLevel option for protocol version 1.  Compression is desirable on
        modem lines and other slow connections, but will only slow down things on fast networks.  The
        default value can be set on a host-by-host basis in the configuration files; see the Compression
        option.

-c cipher_spec
        Selects the cipher specification for encrypting the session.

        Protocol version 1 allows specification of a single cipher.  The supported values are “3des”,
        “blowfish”, and “des”.  3des (triple-des) is an encrypt-decrypt-encrypt triple with three different
        keys.  It is believed to be secure.  blowfish is a fast block cipher; it appears very secure and is
        much faster than 3des.  des is only supported in the ssh client for interoperability with legacy
        protocol 1 implementations that do not support the 3des cipher.  Its use is strongly discouraged
        due to cryptographic weaknesses.  The default is “3des”.

        For protocol version 2, cipher_spec is a comma-separated list of ciphers listed in order of
        preference.  See the Ciphers keyword in ssh_config(5) for more information.

-D [bind_address:]port
        Specifies a local “dynamic” application-level port forwarding.  This works by allocating a socket
        to listen to port on the local side, optionally bound to the specified bind_address.  Whenever a
        connection is made to this port, the connection is forwarded over the secure channel, and the
        application protocol is then used to determine where to connect to from the remote machine.
        Currently the SOCKS4 and SOCKS5 protocols are supported, and ssh will act as a SOCKS server.  Only
        root can forward privileged ports.  Dynamic port forwardings can also be specified in the
        configuration file.

        IPv6 addresses can be specified by enclosing the address in square brackets.  Only the superuser
        can forward privileged ports.  By default, the local port is bound in accordance with the
        GatewayPorts setting.  However, an explicit bind_address may be used to bind the connection to a
        specific address.  The bind_address of “localhost” indicates that the listening port be bound for
        local use only, while an empty address or ‘*’ indicates that the port should be available from all
        interfaces.

-e escape_char
        Sets the escape character for sessions with a pty (default: ‘~’).  The escape character is only
        recognized at the beginning of a line.  The escape character followed by a dot (‘.’) closes the
        connection; followed by control-Z suspends the connection; and followed by itself sends the escape
        character once.  Setting the character to “none” disables any escapes and makes the session fully
        transparent.

-F configfile
        Specifies an alternative per-user configuration file.  If a configuration file is given on the
        command line, the system-wide configuration file (/etc/ssh/ssh_config) will be ignored.  The
        default for the per-user configuration file is ~/.ssh/config.

-f      Requests ssh to go to background just before command execution.  This is useful if ssh is going to
        ask for passwords or passphrases, but the user wants it in the background.  This implies -n.  The
        recommended way to start X11 programs at a remote site is with something like ssh -f host xterm.

        If the ExitOnForwardFailure configuration option is set to “yes”, then a client started with -f
        will wait for all remote port forwards to be successfully established before placing itself in the
        background.

-g      Allows remote hosts to connect to local forwarded ports.

-I pkcs11
        Specify the PKCS#11 shared library ssh should use to communicate with a PKCS#11 token providing the
        user's private RSA key.

-i identity_file
        Selects a file from which the identity (private key) for public key authentication is read.  The
        default is ~/.ssh/identity for protocol version 1, and ~/.ssh/id_dsa, ~/.ssh/id_ecdsa and
        ~/.ssh/id_rsa for protocol version 2.  Identity files may also be specified on a per-host basis in
        the configuration file.  It is possible to have multiple -i options (and multiple identities
        specified in configuration files).  ssh will also try to load certificate information from the
        filename obtained by appending -cert.pub to identity filenames.

-K      Enables GSSAPI-based authentication and forwarding (delegation) of GSSAPI credentials to the
        server.

-k      Disables forwarding (delegation) of GSSAPI credentials to the server.

-L [bind_address:]port:host:hostport
        Specifies that the given port on the local (client) host is to be forwarded to the given host and
        port on the remote side.  This works by allocating a socket to listen to port on the local side,
        optionally bound to the specified bind_address.  Whenever a connection is made to this port, the
        connection is forwarded over the secure channel, and a connection is made to host port hostport
        from the remote machine.  Port forwardings can also be specified in the configuration file.  IPv6
        addresses can be specified by enclosing the address in square brackets.  Only the superuser can
        forward privileged ports.  By default, the local port is bound in accordance with the GatewayPorts
        setting.  However, an explicit bind_address may be used to bind the connection to a specific
        address.  The bind_address of “localhost” indicates that the listening port be bound for local use
        only, while an empty address or ‘*’ indicates that the port should be available from all
        interfaces.

-l 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.

-M      Places the ssh client into “master” mode for connection sharing.  Multiple -M options places ssh
        into “master” mode with confirmation required before slave connections are accepted.  Refer to the
        description of ControlMaster in ssh_config(5) for details.

-m mac_spec
        Additionally, for protocol version 2 a comma-separated list of MAC (message authentication code)
        algorithms can be specified in order of preference.  See the MACs keyword for more information.

-N      Do not execute a remote command.  This is useful for just forwarding ports (protocol version 2
        only).

-n      Redirects stdin from /dev/null (actually, prevents reading from stdin).  This must be used when ssh
        is run in the background.  A common trick is to use this to run X11 programs on a remote machine.
        For example, ssh -n shadows.cs.hut.fi emacs & will start an emacs on shadows.cs.hut.fi, and the X11
        connection will be automatically forwarded over an encrypted channel.  The ssh program will be put
        in the background.  (This does not work if ssh needs to ask for a password or passphrase; see also
        the -f option.)

-O ctl_cmd
        Control an active connection multiplexing master process.  When the -O option is specified, the
        ctl_cmd argument is interpreted and passed to the master process.  Valid commands are: “check”
        (check that the master process is running), “forward” (request forwardings without command
        execution), “exit” (request the master to exit), and “stop” (request the master to stop accepting
        further multiplexing requests).

-o option
        Can be used to give options in the format used in the configuration file.  This is useful for
        specifying options for which there is no separate command-line flag.  For full details of the
        options listed below, and their possible values, see ssh_config(5).

              AddressFamily
              BatchMode
              BindAddress
              ChallengeResponseAuthentication
              CheckHostIP
              Cipher
              Ciphers
              ClearAllForwardings
              Compression
              CompressionLevel
              ConnectionAttempts
              ConnectTimeout
              ControlMaster
              ControlPath
              DynamicForward
              EscapeChar
              ExitOnForwardFailure
              ForwardAgent
              ForwardX11
              ForwardX11Trusted
              GatewayPorts
              GlobalKnownHostsFile
              GSSAPIAuthentication
              GSSAPIDelegateCredentials
              HashKnownHosts
              Host
              HostbasedAuthentication
              HostKeyAlgorithms
              HostKeyAlias
              HostName
              IdentityFile
              IdentitiesOnly
              IPQoS
              KbdInteractiveDevices
              KexAlgorithms
              LocalCommand
              LocalForward
              LogLevel
              MACs
              NoHostAuthenticationForLocalhost
              NumberOfPasswordPrompts
              PasswordAuthentication
              PermitLocalCommand
              PKCS11Provider
              Port
              PreferredAuthentications
              Protocol
              ProxyCommand
              PubkeyAuthentication
              RekeyLimit
              RemoteForward
              RequestTTY
              RhostsRSAAuthentication
              RSAAuthentication
              SendEnv
              ServerAliveInterval
              ServerAliveCountMax
              StrictHostKeyChecking
              TCPKeepAlive
              Tunnel
              TunnelDevice
              UsePrivilegedPort
              User
              UserKnownHostsFile
              VerifyHostKeyDNS
              VisualHostKey
              XAuthLocation

-p port
        Port to connect to on the remote host.  This can be specified on a per-host basis in the
        configuration file.

-q      Quiet mode.  Causes most warning and diagnostic messages to be suppressed.

-R [bind_address:]port:host:hostport
        Specifies that the given port on the remote (server) host is to be forwarded to the given host and
        port on the local side.  This works by allocating a socket to listen to port on the remote side,
        and whenever a connection is made to this port, the connection is forwarded over the secure
        channel, and a connection is made to host port hostport from the local machine.

        Port forwardings can also be specified in the configuration file.  Privileged ports can be
        forwarded only when logging in as root on the remote machine.  IPv6 addresses can be specified by
        enclosing the address in square braces.

        By default, the listening socket on the server will be bound to the loopback interface only.  This
        may be overridden by specifying a bind_address.  An empty bind_address, or the address ‘*’,
        indicates that the remote socket should listen on all interfaces.  Specifying a remote bind_address
        will only succeed if the server's GatewayPorts option is enabled (see sshd_config(5)).

        If the port argument is ‘0’, the listen port will be dynamically allocated on the server and
        reported to the client at run time.  When used together with -O forward the allocated port will be
        printed to the standard output.

-S ctl_path
        Specifies the location of a control socket for connection sharing, or the string “none” to disable
        connection sharing.  Refer to the description of ControlPath and ControlMaster in ssh_config(5) for
        details.

-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 of SSH as a secure transport for other applications (eg.
        sftp(1)).  The subsystem is specified as the remote command.

-T      Disable pseudo-tty allocation.

-t      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.  Multiple -t
        options force tty allocation, even if ssh has no local tty.

-V      Display the version number and exit.

-v      Verbose mode.  Causes ssh to print debugging messages about its progress.  This is helpful in
        debugging connection, authentication, and configuration problems.  Multiple -v options increase the
        verbosity.  The maximum is 3.

-W host:port
        Requests that standard input and output on the client be forwarded to host on port over the secure
        channel.  Implies -N, -T, ExitOnForwardFailure and ClearAllForwardings and works with Protocol
        version 2 only.

-w local_tun[:remote_tun]
        Requests tunnel device forwarding with the specified tun(4) devices between the client (local_tun)
        and the server (remote_tun).

        The devices may be specified by numerical ID or the keyword “any”, which uses the next available
        tunnel device.  If remote_tun is not specified, it defaults to “any”.  See also the Tunnel and
        TunnelDevice directives in ssh_config(5).  If the Tunnel directive is unset, it is set to the
        default tunnel mode, which is “point-to-point”.

-X      Enables X11 forwarding.  This can also be specified on a per-host basis in a configuration file.

        X11 forwarding should be enabled with caution.  Users with the ability to bypass file permissions
        on the remote host (for the user's X authorization database) can access the local X11 display
        through the forwarded connection.  An attacker may then be able to perform activities such as
        keystroke monitoring.

        For this reason, X11 forwarding is subjected to X11 SECURITY extension restrictions by default.
        Please refer to the ssh -Y option and the ForwardX11Trusted directive in ssh_config(5) for more
        information.

-x      Disables X11 forwarding.

-Y      Enables trusted X11 forwarding.  Trusted X11 forwardings are not subjected to the X11 SECURITY
        extension controls.

-y      Send log information using the syslog(3) system module.  By default this information is sent to
        stderr.