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From: smb@ulysses.homer.nj.att.com (Steven M. Bellovin)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: Lifetime of routes added by redirects
Message-ID: <12310@ulysses.homer.nj.att.com>
Date: 21 Oct 89 02:42:33 GMT
References: <3760@sater.cs.vu.nl>
Organization: AT&T Bell Laboratories, Murray Hill
Lines: 13

The host requirements RFCs addresses this point, but the issue is far
from settled.  Basically, they call for hosts to implement some sort
of dead gateway detection code; the route should be squashed at such
times.  If the gateways, negotiating amidst themselves, decide that
a different gateway is now better -- and each gateway is assumed to
know such things -- then the old gateway will send out a new redirect
message.  (Dead gateways can be detected by things like the sudden absence
of ACKs to TCP.)

Personally, I'm not completely convinced.  Dead gateway detection
is often hard, and other factors, notably security considerations,
make me less than fond of redirects in the first place.  But the
RFCs are certainly the place to start.