Subject: traceroute termination on ICMP unreachable
To: None <tech-net@NetBSD.ORG>
From: None <is@NetBSD.ORG>
List: tech-net
Date: 09/04/1997 17:44:53

as a side remark in his PR 4038, Havard Eidnes claimed that (some/most)
routers rate-limit ICMP unreachable messages, so that normally, only e.g.
two of 3 traceroute probes would get the message back.

Now, normally, traceroute terminates if (nunreachables == nprobes) (per hop).
This doesn't work for rate-limiting routers.

Havard proposed to test for (nunreachables && (nunreachables >= (nprobes-1)).
However, this probably won't work for nprobes much > 3, either.

So, do the networking/router experts among us have better formulae to propose?
[Is there any RFC/Internet Draft proposing rate limiting on ICMP?]

	Ignatios Souvatzis