From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ralf Spenneberg <lists@spenneberg.org>
Subject: Re: Dropping RST of SYN
Date: 04 Sep 2003 11:13:20 +0200
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To: Atsushi Nakagawa <atnak@chejz.com>
Cc: Netfilter <netfilter@lists.netfilter.org>

Am Don, 2003-09-04 um 10.50 schrieb Atsushi Nakagawa:
> What iptables table/rule can I use to drop RST (TCP) packets that're in
> reply to SYN?
> This is what I want it to do:
>=20
> -SYN->    [NEW]        -SYN->
>           [CLOSED]     <-RST-
>             ^
>           IF TCP & [NEW]: DROP '<-RST-' & SET [CLOSED]
Using the current state implementation, AFAIK this is not possible.
The RST is already an established packet. There is no way to
differentiate between this RST and a later valid and needed RST packet.
You can only drop all RST packets
-m state --state ESTABLISHED -p tcp --tcp-flags RST,ACK RST,ACK -j DROP

Cheers,

Ralf
--=20
Ralf Spenneberg
RHCE, RHCX

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