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Negative ARP caching [was Re: TCP session disconnection caused byCode Red? ]

  • From: Alex Bligh
  • Date: Mon Aug 06 17:09:12 2001


Probably
a bad idea.  Rate limiting, as RFC 1122 suggests, would seem to be much
better.
Agree that rate-limiting is a good idea (indeed that's INCOMPLETE[n] and
[t1] in my proposal) but I don't see how it helps here.
Or to put it another way:

So if you are storing sufficient state in the OS to do rate-limiting (i.e.
keeping state on incomplete / nonexistant entries too), then put it to
some use, and (say) halve the rate-limit every time one proves
non-existant (and you drop the queued packet(s)), (i.e. twice as
many seconds between ARP packets), down to some minimum, like one
every 5 mins, and reset the rate limit on reception of any IP
packet from that machine and/or successful ARP.

This is almost the same thing as I suggested, but looks more like
rate limiting, with some intelligence as to the rate.

--
Alex Bligh
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