From owner-freebsd-net  Wed Apr 19 11:19:40 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: <20000419115513.A42767@relay.ucb.crimea.ua> from Ruslan Ermilov at "Apr 19, 2000 11:55:13 am"
To: ru@FreeBSD.ORG (Ruslan Ermilov)
Date: Wed, 19 Apr 2000 11:19:33 -0700 (PDT)
Cc: julian@elischer.org, brian@Awfulhak.org, cmott@scientech.com,
	ari@suutari.iki.fi, perhaps@yes.no, net@FreeBSD.ORG,
	erik@whistle.com (Erik Salander)
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Ruslan Ermilov writes:
> > 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.
> > 
> This patch should (hopefully) allow for concurrent PPTP tunnels from
> multiple local PACs to the same remote PNS to work behind NAT (rfc2637
> terminology is being used).
> 
> Could someone please test this patch, since I do not have enough test
> environment here?
> 
> Note please, that you DO NOT need PacketAliasRedirectPptp() for this
> to work.  Just running natd(8) with the default set of options should
> be enough.
> 
> If someone is going to test this, please mail me the output of `natd -v'
> while trying PPTP to the same PNS from two or more local PACs.

I'm not that familiar with the libalias code (erik@whistle.com is
more familiar), but am familiar with PPTP. Are you swizzling the
TCP stream (port 1723) at all? If not, then it's probably not going
to work .. or at least, not when two clients use the same Call ID.

PPTP is like active mode FTP in that the Call ID (FTP -> port #) is
embedded in the TCP stream and must be swizzled. Unlike FTP however,
the TCP stream won't shrink or expand.

-Archie

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


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