ICMP type-3/code-3

[Barry Margolin]

In article <Pine.BSF.4.05.9906241033440.19293-100000 at adam.enteract.com>,
Lance Spitzner  <lspitz at enteract.com> wrote:
>My DNS servers are getting alot of ICMP type-3/code-3
>traffic.  This is Destination unreachable/port unreachable.

This will happen if the client has timed out waiting for a response.  When
the response finally arrives there's no process listening on that port, so
an ICMP Port Unreachable message is returned.

This is normal, although if it happens alot it suggests that there's a
problem with the performance of your server.

-- 
Barry Margolin, barmar at bbnplanet.com
GTE Internetworking, Powered by BBN, Burlington, MA
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