[CentOS] ARP Problem ???

Robert Moskowitz rgm at htt-consult.com
Tue Jun 12 03:34:06 UTC 2007

Craig Van Ham wrote:
> Does any one know if this is normal operating of ARP… Or where to 
> start looking…
> I am seeing a lot of ARP requests for my router IP from the same IP 
> within seconds.
I have seen this. Now I have to remember where!

I think that Netbios browser if configured for Wins-B mode does this. 
Unless there is a Wins server on the subnet.

Per the RFC, an implementation SHOULD maintain an ARP table entry for 10 
minutes from the last time of use (ie 10 minutes of inactivity).

The 10 minute value was determined by two teams of Comer's grad 
students: Which team could bring the DEC down, swap the Ethernet board, 
and get the system back up. The winning team did it in 10 minutes.

Ah, such practical engineering methodologies :)

Many implementation now NEVER age out ARP table entries. They are stuck 
there until they detect an ARP reply (sent out by many systems once they 
are up and running).

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