Re: tcp vulnerability? haven't seen anything on it here...

[Florian Weimer <fw@deneb.enyo.de>]

"David S. Miller" <davem@redhat.com> writes:

> On Wed, 21 Apr 2004 19:27:01 +0200
> "Fabian Uebersax" <fabian.uebersax@ch.tiscali.com> wrote:
>
>> http://www.ietf.org/internet-drafts/draft-ietf-tcpm-tcpsecure-00.txt
>
> Anyone who recommends responding to a RST packet, does not
> understand TCP very well.

This was my thought as well.  Surely you don't want to deploy such a
drastic change to the TCP state engine after just so little
investigation.

In the confined environment of BGP peerings, the risks can be
controlled (RSTs are typically rate-limited on the receiving end
anyway, for example).  On the net as a whole, you have to be
compatible with all implementations ever written.  If some
implementation replied to the ACK cookie with another RST with an
suitable sequence number, there might be a few issues.

(BTW, TCP connections used for BGP typically have port numbers from a
very small set.  So there is no additional randomness from that which
offers any additional protection.)

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