def externalIP()
            joinThread()
            external_ip = getCString()
            r = MiniUPnP.UPNP_GetExternalIPAddress(@urls.controlURL,
                                @data.servicetype,external_ip)
            if r != 0 then
                raise UPnPException.new, "Error while retriving the external ip address. #{code2error(r)}."
            end
            return external_ip.rstrip()
        end
def externalIP()
            joinThread()
            external_ip = getCString()
            r = MiniUPnP.UPNP_GetExternalIPAddress(@urls.controlURL,
                                @data.servicetype,external_ip)
            if r != 0 then
                raise UPnPException.new, "Error while retriving the external ip address. #{code2error(r)}."
            end
            return external_ip.rstrip()
        end
Returns the external network ip