From owner-freebsd-net  Mon Apr 17 17:14:32 2000
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From: Archie Cobbs <archie@whistle.com>
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Subject: Re: Improved PPTP support for libalias(3)
In-Reply-To: <20000417170542.A61926@relay.ucb.crimea.ua> from Ruslan Ermilov at "Apr 17, 2000 05:05:42 pm"
To: ru@FreeBSD.ORG (Ruslan Ermilov)
Date: Mon, 17 Apr 2000 17:14:25 -0700 (PDT)
Cc: julian@elischer.org (Julian Elischer),
	brian@Awfulhak.org (Brian Somers),
	cmott@scientech.com (Charles Mott), ari@suutari.iki.fi (Ari Suutari),
	perhaps@yes.no (Eivind Eklund), net@FreeBSD.ORG
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Ruslan Ermilov writes:
> > does this mean that only one PC at a time behind a NAT wall, can access a
> > particular machine?
> > i.e. two visitors with their own laptops from the same place,
> > cannot go back to the same host to read their mail..?
> > This is not a BAD restriction, but it is a restriction..
> >  
> If you mean two PCs, each with their own tunnel to the same host, this
> will not work.  The problem here is that we need some "tag" to use with
> source and destination IP addresses, to successfully de-alias packets
> coming in.  For TCP and UDP packets, there are port numbers.  For ICMP
> echo/timestamp packets, there is an ID field.  But unfortunately, there
> seems to be no such "tag" with PPTP protocols.

Sure there is: the Call ID. 

We are probably going to implement the remaining bit of this here
at Whistle in the next couple of weeks.. and will submit when done.

-Archie

___________________________________________________________________________
Archie Cobbs   *   Whistle Communications, Inc.  *   http://www.whistle.com


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