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To: Andrew Stesin <stesin@gu.net>
cc: freebsd-hackers@freebsd.org
Subject: Re: FreeBSD as an ISDN Router 
In-reply-to: Your message of "Thu, 16 Jan 1997 11:05:54 +0200."
             <Pine.BSF.3.95.970116103950.3924F-100000@trifork.gu.net> 
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Date: Thu, 16 Jan 1997 21:47:07 +0000
From: Brian Somers <brian@awfulhak.demon.co.uk>
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> Dear Brian,
> 
> On Thu, 16 Jan 1997, Brian Somers wrote:
> 
> > The alias stuff converts *every* port number for a given interface, making 
> > what appears to be going on and what's actually going on into two completely 
> > different things.
> 
> 	Would you mind explaining me please, how the stuff discussed
> 	here differs from what IPfilter (with NAT "range-to-range"
> 	functionality) (see http://coombs.anu.edu.au/~avalon
> 	for details) does?

It solves the same problems, but the alias code has some packet-mangling stuff 
built in to deal with ftp PORT commands, realaudio etc.  It also manages 
fragments and ICMP packets.

The *real* advantage is that it's not filling the tcp stack with clag, whereas 
ipfilter does (not that much clag, but it's "unclean").

The *real* disadvantage is that it only works for user-level ppp.

The best solution (the one I'm going to tackle) is the masqd daemon sitting on 
top of ipfw 'divert'd packets.  No kernel mods, one daemon program and it 
works on any interface.... wonderful !

-- 
Brian <brian@awfulhak.demon.co.uk>, <brian@freebsd.org>
      <http://www.awfulhak.demon.co.uk/>
Don't _EVER_ lose your sense of humour....