[c-nsp] 6500 ARPing behaviour

[PW]

Hi All,

Recently we are seeing some unusual behaviour with one of our 6500 switches,
where it is broadcasting ARPs for every IP address sequentially within the
subnet of one of the SVIs every now and then.

There are two streams of sequential broadcasts that I can see, with one
starts a few minutes later than the other. Not all IPs in the subnet can be
resolved as those IPs are not used.

I have captured the ARP traffic for an actual host within the subnet, and
apart from an ARP response from the host back to the 6500 switch, there is
really nothing else happening after that.

Any one have an idea of why the switch is behaving this way? I initially
thought some external hosts is trying to ping every address on the subnet,
but after I found out apart from the ARP traffic there's nothing else, I'm
not so sure.

Thanks in advance!

cheers,
Patrick