tramp: Gateway methods

 
 4.5 Gateway methods
 ===================
 
 Gateway methods are for proxy host declarations (SeeMulti-hops) so
 as to pass through firewalls and proxy servers.  They are not like the
 other methods that declare direct connections to a remote host.
 
    A gateway method always comes with a port setting.  TRAMP targets the
 port number with the gateway method ‘localhost#random_port’ from where
 the firewall or proxy server is accessed.
 
    Gateway methods support user name and password declarations for
 authenticating the corresponding firewall or proxy server.  Such
 authentication can be passed through only if granted access by system
 administrators.
 
 ‘tunnel’
 
      This method implements an HTTP tunnel via the ‘CONNECT’ command
      (conforming to RFC 2616, 2817 specifications).  Proxy servers using
      HTTP version 1.1 or later protocol support this command.
 
      For authentication, this protocol uses only ‘Basic Authentication’
      (see RFC 2617).  When no port number is specified, this protocol
      defaults to ‘8080’.
 
 ‘socks’
 
      The ‘socks’ method connects to SOCKSv5 servers (see RFC 1928) and
      supports ‘Username/Password Authentication’.
 
      The default port number for the socks server is ‘1080’, if not
      specified otherwise.