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Date:      Wed, 24 Jan 2001 18:00:10 -0500 (EST)
From:      Alwyn Goodloe <agoodloe@gradient.cis.upenn.edu>
To:        Luigi Rizzo <rizzo@aciri.org>
Cc:        hackers@FreeBSD.ORG
Subject:   Re: Divert Sockets & Fragmentation
Message-ID:  <Pine.SOL.4.21.0101241755480.2862-100000@gradient.cis.upenn.edu>
In-Reply-To: <200101242245.f0OMjUX20166@iguana.aciri.org>

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I was originally diverting udp packets heading to a particular port then
I flushed the ipfw and tried:

 ipfw  add 60000 divert 4422 ip all from any to any in
and still no packets are received by recvfrom(). Would the port numbers 
matter for this case.

Alwyn
agoodloe@gradient.cis.upenn.edu
 




On Wed, 24 Jan 2001, Luigi Rizzo wrote:

> it depends on what template do you use for matching.
> the firewall acts before reassembly, so for the fragments you will
> not be able to see the port numbers.
> 
> 	cheers
> 	luigi
> 
> > I have been using divert sockets for a while sending small (< MTU) UDP
> > packets and everything worked fine. Now that the UDP packets are larger
> > (>MTU = 1500) and hence fragmentation is taking place there seems to be a
> > problem. tcpdump tells me that the fragmented packets arrive but it seems
> > that they are never diverted. I say this because after they are received
> > recvfrom () never gets the packet. I've done things like play with the
> > nbytes field of the recvfrom() fn. without any success. Any
> > suggestions, I'm sure its something stupid.
> > 
> > 
> > Alwyn
> > agoodloe@gradient.cis.upenn.edu
> > 
> > 
> > 
> > 
> > 
> > To Unsubscribe: send mail to majordomo@FreeBSD.org
> > with "unsubscribe freebsd-hackers" in the body of the message
> > 
> 
> 



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