default gateway

[altaf007]

We have 4500 switch running layer 3 IOS and eigrp. It has one

user VLAN. Users on that vlan can set their default gateway to any router on

our network and it works. I am curious why this is working ? I thought you

always need to set default gateway to be as swith vlan interface for the end

users.

chasis : 4506

Sup IV WS-4515

IOS: cat4000-i5k9ls-mz.122-25.EWA6.bin

[dgahm]

That is called proxy ARP. When the router hears an ARP request for an address on a different subnet that it knows how to reach it will respond with its MAC address.

It is still a good idea to use the correct default gateway as someone might disable proxy arp on the interface.

http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080094adb.shtml

Please rate helpful posts.

Dave