nanog mailing list archives

Re: Code Red


From: John Kristoff <jtk () depaul edu>
Date: Fri, 20 Jul 2001 09:43:35 -0500


Jeff Ogden wrote:
is causing network problems due to heavy ARP loads when the local
site routers ARP for what turn out to be unused IP addresses.  This
is an issue when there are large blocks of IP addresses behind a
router. It is less of a problem when there is a relatively small
number of IP addresses behind a router (say one class C worth). Are
others seeing these sorts of problems?  What strategies are there for
dealing with this?

If addresses are contiguous, perhaps you could blackhole some of them
temporarily.  It might be nice if there was a way to take a current ARP
table and freeze it.  That is, mark all the entries as permanent, then
turn off ARP or dump destination IPs not in the ARP table into the bit
bucket.  As long as the router continues to respond to ARP requests,
this might be a short term fix for that type of event.

John


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