Re: [tcpm] TCP zero window timeout?

Joe Touch <touch@ISI.EDU> Sun, 27 August 2006 02:59 UTC

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Date: Sat, 26 Aug 2006 19:58:43 -0700
From: Joe Touch <touch@ISI.EDU>
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To: MURALI BASHYAM <murali_bashyam@yahoo.com>
Subject: Re: [tcpm] TCP zero window timeout?
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Cc: "Mahdavi, Jamshid" <jamshid.mahdavi@bluecoat.com>, tcpm@ietf.org, "Anantha Ramaiah \(ananth\)" <ananth@cisco.com>, Fernando Gont <fernando@gont.com.ar>
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MURALI BASHYAM wrote:
> Fernando
> 
> I collaborated with mahesh on this, so let me try
> making the case for it a little better.
> 
> The problem was found on a TCP proxy, which does not
> have any applicaton awareness. In fact application
> awareness is not a goal in that environment. Hence the
> TCP level solution.

Application-aware proxies are one thing (and they would be able to
adjust fine here). TCP proxies for splice-like, transport-only gateways
are already known to break so many things it's not clear that
considering that as a special case is a good argument for modifying TCP.
It's a better argument not to use TCP that way.

> Having said that, i'd say this timeout is in the same
> spirit as the upper bound on the retransmit mechanism
> of TCP. TCP could indefinitely retransmit and have the
> application timeout too, correct? The problem is that
> TCP has a persist state which can potentially exist
> infinitely long  and which lends itself to abuse by a
> malicious peer. 

TCP is not intended to be robust to security attacks. A peer that can
establish a TCP connection is already presumed to be a non-attacker at
the TCP level, IMO.

JOe

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