Kenneth, I believe you were correct, it was proxy-arp causing my issue. Thank you very much for the help.
-Marc On Wed, Mar 2, 2011 at 9:52 PM, Matlock, Kenneth L <[email protected]>wrote: > What you may be seeing is a feature called 'proxy arp'. I'm not 100% sure > of hte origins of it, but I know that in the real world it masks > netmask/gateway problems on the clients. > > How? Well the switch sees an ARP request for something, and if it has a > valid route to it, it sends out a proxy arp reply, with it's MAC instead. > This allows the misconfigured client to send the packet as Layer2 to the > switch, which can then route the packet. So if the client has a bad netmask > or gateway, it will be ARPing for hosts that are not local, and the switch > will 'fix' it. > > In practice I turn it off on all my boxes, because all it REALLY does for > us is mask client issues, and fills up the ARP tables :) > > Ken > > ________________________________ > > From: [email protected] on behalf of marc abel > Sent: Wed 3/2/2011 7:46 PM > To: [email protected] > Subject: [OSL | CCIE_RS] Arp Watch Flip Flops > > > > I hope you don't mind me asking a real world question here, I think the > content is plenty relevant to the studies at hand. > > I have ARP watch running on my network and I am regularly seeing a flip > flop > occur from one of the hosts in a fairly new VLAN. Two 4506's have an > interface in this VLAN with HSRP running between them. The host IP keeps > flipping between the MAC of the laptop, and the MAC of the standby switch. > This doesn't happen rapidly, but maybe a few times a day. To me this > implies > that the secondary switch is occasionally answering ARP query's for the > host's IP address. Can anyone give an explanation or a theory of why the > switch would do that? > > Thank you, > > Marc > _______________________________________________ > For more information regarding industry leading CCIE Lab training, please > visit www.ipexpert.com > > > _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
