ARP entry changed

[sullim01]

I have an arp entry that changed from my pix to another router interface and I'm not sure why. This has happened twice. Unfortunately the router causing the issue is managed by someone else so I can't see it's config. I am waiting for call ack so I can alteast get a soft copy of it. Anyway, I removed it's connection and cleared my arp to fix the problem but I would like to get to the bottom of it. Any suggestions?

Here is my environment......

Internet

--> RouterA

--> Layer 2 Switch

--> RouterB

--> Pix

[milan.kulik]

Hi,

I'd guess the problem was caused by the other router misconfiguration using your pix IP address on the router interface.

Generally, it's very difficult to "glue" your IP to the correct MAC address. There are some new IOS features available which might help:

Dynamic ARP Inspection (http://www.cisco.com/en/US/customer/products/hw/switches/ps708/products_configuration_guide_chapter09186a00802011c2.html#wp1218243)

DHCP Snooping and IP Source Guard (http://www.cisco.com/en/US/customer/products/hw/switches/ps708/products_configuration_guide_chapter09186a00801eb955.html)

Regards,

Milan