Firewall Wizards mailing list archives

RE: Source of T/TCP traffic


From: Dave Killion <Dkillion () netscreen com>
Date: Tue, 9 Sep 2003 09:18:30 -0700

From what I've seen, and I could be dead-wrong, is that IIS and IE form a
T/TCP bond when connecting.  IE will actually try T/TCP first, and fall
back to normal TCP after failing.  This is how IIS-served webpages load so
quickly on IE.  You can tell when you're loading a non-IIS served page
with IE because there's a bit of a pause while T/TCP fails.

So three cheers to Microsoft for putting this half-dead protocol on life
support.  ;)

Dave Killion
Senior Security Engineer
Security Group, NetScreen Technologies, Inc.



-----Original Message-----
From: Knut Bjornstad [mailto:kbjo () interpost no]
Sent: Tuesday, September 09, 2003 4:23 AM
To: firewall-wizards () honor icsalabs com
Subject: [fw-wiz] Source of T/TCP traffic


Our IDS are seeing a lot of peculiar T/TCP traffic - the alerts on this
is no problem in itself - I can easily disable them. But when I try to
analyze the traffic, it seems like ordinary web traffic from various MS
IE sources. Now T/TCP is - according to my impression - a halfdead
attemt at speeding up TCP, and nothing I would associate with this kind
of everyday events. My theory is that this is coused by some firewall or
similar product that modidfies outgoing traffic by adding the neccessary
TCP option to the packets.
First question: Do anyone in this forum know of a product that does
something like that (I suspect something from Checkpoint, but I am not
sure about that)?

Second question: Given that T/TCP has problematic security, can ordinary
firewalls handle the protocol by setting up relevant rules?

--
--Knut Bjornstad -- ErgoIntegration AS ---Oslo, Norway-------
--kbjo () interpost no -- t:47 23 14 53 36 -- mob: 901 15 917 --
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