Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 20 Mar 2003 09:08:55 +1100
From:      Gregory Bond <gnb@itga.com.au>
To:        Luigi Rizzo <rizzo@icir.org>
Cc:        "Simon L. Nielsen" <simon@nitro.dk>, "Crist J. Clark" <cjc@FreeBSD.ORG>, Wiktor Niesiobedzki <w@evip.pl>, freebsd-ipfw@FreeBSD.ORG, gnb@itga.com.au
Subject:   Re: Prioritizing empty TCP ACKs with ipfw? 
Message-ID:  <200303192208.JAA01920@lightning.itga.com.au>
In-Reply-To: Your message of Wed, 19 Mar 2003 00:41:38 -0800.

next in thread | raw e-mail | index | archive | help
> >      iplenmin len
> >              Matches IP packets whose total length, including header and da
> ta,
> >              is minimum len bytes (packet length >= len).

If we're going to all that trouble, why not add function/keyword to
calculate payload length (for IP/UDP/TCP), after accounting for IP and
TCP options.  This would allow unambiguous detection of acks
(payloadlen < 1) and pretty good detection of interactive telnet
traffic and the like.  It's pretty easy and cheap to do this calc in C
but a fair bit harder to do in FW rules.

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-ipfw" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?200303192208.JAA01920>