From: Chris Brenton <cbrenton@chrisbrenton.org>
To: Taylor Grant <gtaylor@riverviewtech.net>
Cc: netfilter <netfilter@lists.netfilter.org>
Subject: Re: TCP packets with RST flag set but **not** ACK flag OK??
Date: Tue, 12 Apr 2005 10:41:57 -0400 [thread overview]
Message-ID: <1113316917.2007.26.camel@grendel> (raw)
In-Reply-To: <425B779B.60907@riverviewtech.net>
On Tue, 2005-04-12 at 03:24, Taylor Grant wrote:
>
> In short, deciding if the ACK and RST flags to together or not is about like deciphering the English language.
Luckily I speak native English and Hex. ;-) Try this:
In one terminal window run:
tcpdump -nn -v -i lo
In another terminal window run:
hping -A -c 1 -p 5 127.0.0.1
hping -S -c 1 -p 5 127.0.0.1
You'll see the first packet causes a RST only to be returned. The second
will cause a RST/ACK to be returned. So either condition is a
possibility and a Netfilter rule base needs to handle both of them
appropriately.
HTH,
Chris
next prev parent reply other threads:[~2005-04-12 14:41 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-04-11 19:18 TCP packets with RST flag set but **not** ACK flag OK?? Christian Seberino
2005-04-11 19:49 ` Chris Brenton
2005-04-11 21:57 ` Taylor, Grant
2005-04-12 0:36 ` Chris Brenton
2005-04-12 2:32 ` Grant Taylor
2005-04-12 4:06 ` Chris Brenton
2005-04-12 4:01 ` Taylor Grant
2005-04-12 7:24 ` Taylor Grant
2005-04-12 14:41 ` Chris Brenton [this message]
2005-04-12 4:22 ` Taylor Grant
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