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Re: Fw: oops/bug in tcp, SACK doesn't work?

To: "Marty Poulin" <mpoulin@xxxxxxxxxxx>
Subject: Re: Fw: oops/bug in tcp, SACK doesn't work?
From: Harald Welte <laforge@xxxxxxxxxxxx>
Date: Sat, 28 Jul 2001 00:44:47 -0300
Cc: <netdev@xxxxxxxxxxx>
In-reply-to: <01ad01c11621$7ce50440$0b32a8c0@xxxxxxxxxxx>; from mpoulin@xxxxxxxxxxx on Thu, Jul 26, 2001 at 05:22:13PM -0500
References: <01ad01c11621$7ce50440$0b32a8c0@xxxxxxxxxxx>
Sender: owner-netdev@xxxxxxxxxxx
User-agent: Mutt/1.3.17i
On Thu, Jul 26, 2001 at 05:22:13PM -0500, Marty Poulin wrote:

> > Perhaps this has been covered somewhere before, but for some reason it
> > doesn't look like the 2.4.7 (and previous 2.4.x?)  kernels responds to
> > SACK correctly. Instead of just resending the missing packet Linux resends
> > the entire packet stream as if it never received the SACK.

Please note that the netfilter nat protocol helpers for ftp (and irc as well as
other protocols in patch-o-matic) delete the SACKPERM option on-the-fly 
from all packets.

It has to, as you run in neverending complications as soon as the nat helper
has to alter the tcp sequence numbers, etc.

So make sure that your tests are not done with ftp control connections when
you do nat and have the helper running.

> > Marty Poulin
> > vandal@xxxxxxxxxxx

-- 
Live long and prosper
- Harald Welte / laforge@xxxxxxxxxxxx                http://www.gnumonks.org
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