I'm trying to simulate some strange behavior on Linux for testing. Machine A and machine B are on different subnets. On A, the gateway to B's subnet is is through gateway G. So, if I send a packet on A to B, then on the A<->G link, the packets have a destination MAC address of Ethernet(G). I would like to force this destination MAC address to something other than G's MAC address. Concrete example: Machine A's address is 10.3.3.54, machine B's address is 10.2.2.32. A has a route entry specifying that the 10.2/16 network is reachable through Gateway G, at 10.3.3.40. I want to change the destination MAC address used for packets sent from A to B. I tried using the 'arp' utility (this is on a Redhat 8 box): MachineA # arp -s 10.2.2.41 a1:a1:a1:a1:a1:a1 SIOCSARP: Network is unreachable I tried using 'ip neigh add', which _did_ create a permanent arp entry to be created. But, pinging 10.2.2.41 shows that the "a1:a1:a1:a1:a1:a1" MAC address is not being used. So is this possible? If so, how? The context here: I'm testing a transparent proxy setup. When the tproxy communicates with a server, the tproxy NAT's its IP addresses to match the client, but leaves its Ethernet addresses alone. But - when the tests run against a Celera, it replies back to the proxied, non-local IP address with the MAC address of the tproxy, and _not_ of the proper gateway. This revealed a bug in the tproxy code. But I'd like to recreate this scenario, if possible, and without the Celera. Thanks, Al - : 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
