# Pastebin cXdzDbp4
    def _update_external_gateway_mac(self, fip, learning_mac):
        net_id = fip.floating_network_id
        gw_mac = self.external_gateway_mac.get(net_id, None)
        if not gw_mac or gw_mac != learning_mac:
            self.external_gateway_mac[net_id] = learning_mac
            self._install_dnat_egress_rules(fip)