Cisco WS-C6509-E Arp Cache Corruption Issue

arpciscoswitch

We are having an issue with our Catalyst 6500 switch where we suspect that the ARP cache is being corrupted. This presents itself with the following symptoms:

  1. When you attempt to ping a system which has not been resolved before, the first ping response times out, and each proceeding one succeeds:
    Pinging foo.network.com [xxx.xx.xx.xx] with 32 bytes of data:
    Request timed out.
    Reply from xxx.xx.xx.xx: bytes=32 time=5ms TTL=55
    Reply from xxx.xx.xx.xx: bytes=32 time=3ms TTL=55
    Reply from xxx.xx.xx.xx: bytes=32 time=3ms TTL=55

  2. When the corruption issues occurs, every other ping times out:
    Pinging foo.network.com [xxx.xx.xx.xx] with 32 bytes of data:
    Reply from xxx.xx.xx.xx: bytes=32 time=5ms TTL=55
    Request timed out.
    Reply from xxx.xx.xx.xx: bytes=32 time=5ms TTL=55
    Request timed out.

  3. Clearing the ARP cache temporarily resolves the issue. To clear the ARP cache we use the commands:
    clear arp cache
    clear ip cache
    This fixes it, but it is sure to happen again.

Details on the switch:

IOS ™ s72033_rp Software (s72033_rp-PK9SV-M), Version 12.2(17d)SXB8, RELEASE SOFTWARE (fc2)

cisco WS-C6509-E (R7000) processor (revision 1.1)

Any help appreciated,
Thanks

CLARIFICATION: We have the network that we manage, and then we are plugged into the corporate network. All requests to machines inside of the network that we manage work fine. We are only having problems with machines on the other network.

Best Answer

I would suggest you to open a case to Cisco.
They will be able to check for know bugs on your IOS version and will ask you configuration details that you may don't want to publish here. (but if you want you can put the result of a sh tech somewhere it could help us)
Also doest it append after a reboot or did it start to get corrupt after a long uptime ?

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