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From: Alexander Motin <mav@alkar.net>
To: freebsd-ipfw@freebsd.org
Date: Tue, 17 Feb 2004 11:55:36 +0200
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Subject: Generating 'Fragment Needed but DF was Set' ICMP & Dummynet
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Hi!

I observe a strange thing. When I create dummynet pipe on output router 
interface with lower MTU system stops to generate 'Fragment Needed but 
DF was Set' ICMP in cases when it must. If I create this pipe on 
incoming interface there is no problem.

I check this on many routers under 4.8 and 5.2 FreeBSD.

Is this a bug or feature? :) How pipes can be created leaving ICMP 
generation working?

-- 
Alexander Motin