From owner-freebsd-arch  Thu Jun 22 15:43:18 2000
Delivered-To: freebsd-arch@freebsd.org
Received: from bubba.whistle.com (bubba.whistle.com [207.76.205.7])
	by hub.freebsd.org (Postfix) with ESMTP id D178B37B752
	for <arch@FreeBSD.org>; Thu, 22 Jun 2000 15:43:13 -0700 (PDT)
	(envelope-from archie@whistle.com)
Received: (from archie@localhost)
	by bubba.whistle.com (8.9.3/8.9.2) id PAA94706;
	Thu, 22 Jun 2000 15:39:36 -0700 (PDT)
From: Archie Cobbs <archie@whistle.com>
Message-Id: <200006222239.PAA94706@bubba.whistle.com>
Subject: Re: Software detection of link integrity
In-Reply-To: <200006222220.XAA02751@hak.lan.Awfulhak.org> from Brian Somers at "Jun 22, 2000 11:20:00 pm"
To: brian@Awfulhak.org (Brian Somers)
Date: Thu, 22 Jun 2000 15:39:36 -0700 (PDT)
Cc: archie@whistle.com (Archie Cobbs),
	phk@critter.freebsd.dk (Poul-Henning Kamp),
	tlambert@primenet.com (Terry Lambert),
	winter@jurai.net (Matthew N. Dodd), arch@FreeBSD.org,
	brian@hak.lan.awfulhak.org
X-Mailer: ELM [version 2.4ME+ PL54 (25)]
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: owner-freebsd-arch@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

Brian Somers writes:
> > > >> But a dial on demand line is a layered concept.  You have a transient
> > > >> physical line with a layer on top of it which pretends to be a
> > > >> permanent line.
> > > >
> > > >Which unfortunately doesn't work with a dynamically assigned IP 
> > > >number.
> > > 
> > > That is a different story alltogether...
> > 
> > On the InterJet, if it's dynamic IP and there is no other IP address
> > to use, we actually make one up! Once connected, we renumber the
> > interface of course.
> 
> How do you deal with the first connection problem - where that first 
> packet that causes the dial ends up with an incorrect src address ?
> 
> ppp(8) does it when NAT is enabled by keeping the old interface 
> address as an alias and just NATing the first connection.

That packet eventually gets dropped/ignored, and subsequent packets
will be correct, because when/if the interface gets renumbered we
restart whatever proceses need to be restarted. We can do this
because we "know" what's running and what needs a restart in this
case.

-Archie

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


To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-arch" in the body of the message