ARP table growing up with many IPs mapped to the same MAC address

Unanswered Question
Nov 30th, 2009
User Badges:


I'm wondering if somebody has ever experienced the same problem and can share some comments. The arp table on our 2811 was growing up with entries mapping various IPs to the same MAC address. We got up to 20 entries with this kind of mapping. 5 to 8 hosts on the network were affrected by this problem. Hosts in questions lost their dhcp address and were not able to get the new one. The problem disapeared after 1 - 2 hours by itself and never happened again so far.

thanks a lot

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
Panos Kampanakis Mon, 11/30/2009 - 15:24
User Badges:
  • Cisco Employee,

It could have been a host impersonating those ip addresses.

If there was firewall or other device that was doing natting and was proxy-arping for these ip addresses it could explain the issue.

I hope it helps.



This Discussion