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From: Miguel Angel Amador L <amador@puc.cl>
To: netfilter@lists.netfilter.org
Subject: Re: bad tcp packets
Date: Tue, 23 Nov 2004 09:42:24 -0300	[thread overview]
Message-ID: <1101213743.32475.37.camel@JOKER.INFOWORLD.CL> (raw)
In-Reply-To: <web-23112413@infinito.it>



El mar, 23-11-2004 a las 09:18, hamals@infinito.it escribió:
> Hello to everyone
> 
> I'm reading "Iptables Tutorial 1.1.19" by Oskar 
> Andreasoon, and I cant understand these bad packets rules
> 
> 
> $IPTABLES -N bad_tcp_packets
> #
> #
> # bad_tcp_packets chain
> #
> $IPTABLES -A bad_tcp_packets -p tcp --tcp-flags SYN,ACK 
> SYN,ACK \
> -m state --state NEW -j REJECT --reject-with tcp-reset

May be that you can't got the three flags on, in the same packet


> $IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state 
> --state NEW -j LOG \
> --log-prefix "New not syn:"

> $IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state 
> --state NEW -j DROP

May be, if the packet haven't the syn flags on, the packet is not new

> someone could explain me why that are bad tcp packets?
I don't secure, but i thing that is this.
regards

 Miguel Amador

> Thanks
> 
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  reply	other threads:[~2004-11-23 12:42 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-11-23 12:18 bad tcp packets hamals
2004-11-23 12:42 ` Miguel Angel Amador L [this message]
2004-11-23 13:49 ` Jason Opperisano
2004-11-23 13:59 ` Frank Gruellich
  -- strict thread matches above, loose matches on Subject: below --
2004-11-23 13:39 Scott Knake

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