Proxy ARP

[akaurbedi]

Do we need proxy arp in routers for source having routing intelligence to reach the destination.

Consider a routing scenario where 3 routers are connected in a WAN.Node A connected to 1st router has the route to reach destination node B connected to the third router.Intermediate routers have the route to reach the destination network.Is proxy arp required in any of the router in this scenario?

[Richard Burts]

ARP should be a function that occurs only on the local subnet. If a machine does ARP for something that is not on the local subnet then proxy arp may be needed for connectivity to be established. But that would be the result of something not being correctly configured.

So long as machines are correctly configured and configured consistently there should be no need for proxy arp.

HTH

Rick

[cadet alain · Accepted solution]

Hi,

proxy-arp is considered a security breach and is disabled by most ISPs. It is used in ethernet network only.

on Cisco routers it is the only way to make a static route pointing to an ougoing multiaccess interface( ethernet) work

because the router considers all destinations are reachable out this interface and are in the same network so it will arp for the destination and not the next-hop but the next-hop seeing this arp request will respond with its own mac address if it knows about the destination.

So in your case I don't see the need for proxy-arp.

Regards.

Alain

Don't forget to rate helpful posts.

[akaurbedi]

Thanks a lot for the replies !!

Now,what I understood in this case,Node A will just send the ARP to the next hop interface defined in static route and It will be normal ARP not a proxy ARP..correct?

[cadet alain]

Hi,

yes.

Regards.

Alain

Don't forget to rate helpful posts.

[akaurbedi]

Thanks.......

[akaurbedi]

Alain,

Your reply was really helpful but unable to edit the correct rating.

Thanks..