So, According to RFC 1027: http://www.ietf.org/rfc/rfc1027.txt === 2.4 Sanity checks If the IP networks of the source and target hosts of an ARP request are different, an ARP subnet gateway implementation should not reply. This is to prevent the ARP subnet gateway from being used to reach foreign IP networks and thus possibly bypass security checks provided by IP gateways. === According to RFC 985: http://www.ietf.org/rfc/rfc0985.txt?number=985 === A.3. ARP datagram An ARP reply is discarded if the destination IP address does not match the local host address. An ARP request is discarded if the source IP address is not in the same subnet. It is desirable that this test be overridden by a configuration parameter, in order to support the infrequent cases where more than one subnet may coexist on the same cable (see RFC-925 for examples). An ARP reply is generated only if the destination protocol IP address is reachable from the local host (as determined by the routing algorithm) and the next hop is not via the same interface. If the local host functions as a gateway, this may result in ARP replies for destinations not in the same subnet. === Linux is doing the things _WRONG_ and on its own way without any switch to change its behaviour. Regards, Carlos Velasco - : send the line "unsubscribe linux-net" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html