Link a server.
        Required arguments:
        * server - Server to link with.
        * port - Port to use.
        Optional arguments:
        * r_server=None - Link r_server with server.

def s_connect(self, server, port, r_server=None):
        """
        Link a server.
        Required arguments:
        * server - Server to link with.
        * port - Port to use.
        Optional arguments:
        * r_server=None - Link r_server with server.
        """
        with self.lock:
            if not r_server:
                self.send('CONNECT %s %s' % (server, port), error_check=True)
            else:
                self.send('CONNECT %s %s %s' % (server, port, \
                                    r_server), error_check=True)