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Date: Mon, 02 May 2005 18:12:03 +0200
From: Andre Oppermann <andre@freebsd.org>
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To: Matthew Sullivan <matthew@uq.edu.au>
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cc: freebsd-current@freebsd.org
Subject: Re: DF (Don't frag) issues
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Matthew Sullivan wrote:
> Andre Oppermann wrote:
> 
>> Matthew Sullivan wrote:
>>
>>> Give me the switches you want on tcpdump and I'll be happy to provide 
>>> the packets ;-)
>>
>> This should do the trick:
>>
>>  tcpdump -n -p -i fxp0 -s 128 -w dump
>>
> Ok this is what you have:
> 
> root@scorpion:~# tcpdump -n -p -i fxp0 -s 128 -w pktdump not port 24
> 
> and it's at: http://scorpion.sorbs.net/ICMP/pktdump

Ok, this is the problem:

  MTU of next hop: 0

Have you installed my patch on the gateway machine too, or only on your
host?

MTU of next hop should not be zero under normal circumstances.  It indicates
a bug somewhere in the normal IP forwarding path.

Is this the correct packet flow:

  ... --> dc0 --> gif0 --> IPSec --> fxp0 --> Internet --> ...

-- 
Andre