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Network Security Focus-IDS
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Re: TCP Sack processing

Subject: Re: TCP Sack processing
Date: Sun, 14 Aug 2005 12:42:39 -0400
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On Aug 13, 2005, at 8:10 AM, Joel Esler wrote:

IIRC, Snort's preprocs do a very good job of keeping that state stuff
in combination between Stream4 and the new frag3.  Basically this is
my opinion, and I need someone from SF to back me up.

Snort's stream4 module is "clocked" by received ACKs from the receiving side of the connection, SACKs don't appear to me to influence our reassembly behavior because we typically don't want to process a collection of segments until we know that the other side of the connection has received them. I'd say that in the case of Snort's current stream reassembler, SACK processing isn't necessary.


    -Marty


- -- Martin Roesch - Founder/CTO, Sourcefire Inc. - +1-410-290-1616 Sourcefire - Discover. Determine. Defend. roesch@sourcefire.com - http://www.sourcefire.com Snort: Open Source Network IDS - http://www.snort.org


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