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From: "fooler" <fooler@skyinet.net>
To: "Jesper Wallin" <jesper@hackunite.net>,
	=?iso-8859-1?Q?Dag-Erling_Sm=F8rgrav?= <des@des.no>
References: <200507051428.j65ESjJu001522@caligula.anu.edu.au><42CAA478.7010806@hackunite.net>
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Date: Wed, 6 Jul 2005 14:11:40 +0800
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Cc: freebsd-security@freebsd.org, Darren Reed <avalon@caligula.anu.edu.au>
Subject: Re: packets with syn/fin vs pf_norm.c
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----- Original Message ----- 
From: "Dag-Erling Smørgrav" <des@des.no>
To: "Jesper Wallin" <jesper@hackunite.net>
Cc: <freebsd-security@freebsd.org>; "Darren Reed"
<avalon@caligula.anu.edu.au>
Sent: Wednesday, July 06, 2005 1:39 PM
Subject: Re: packets with syn/fin vs pf_norm.c


> The TCP_DROP_SYNFIN option should be removed; it has long outlived its
> original purpose (which was to prevent nmap identification of IRC
> servers which didn't run ipfw for performance reasons, back in the 3.0
> days)

i vote not to remove because it just an option there whether you want it or
not for added protection for OS fingerprinting...

standard tcp is the most rampant used than t/tcp and most (or all) tcp
modules are not combining syn + fin flag in a tcp datagram for normal tcp
transaction...

fooler.