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	id smauREDmb; Tue Dec 10 18:53:52 1996
Reply-To: <SimsS@IBM.Net>
From: "Steve Sims" <SimsS@IBM.Net>
To: "Martin Renters" <martin@tdc.on.ca>
Cc: <jkh@time.cdrom.com>, <nate@mt.sri.com>, <freebsd-hackers@freebsd.org>
Subject: Re: PPP with network address translation
Date: Tue, 10 Dec 1996 13:52:48 -0500
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Martin Renters <martin@tdc.on.ca> is on the record:
> 
> > 3) Settle for once and all whether it's Jordan's '-alias' flag in the
command
> > line or Martin's 'set nat on|off' (Which I think is more elegant, at
least in
> > theory).
> 
> Actually, I like Jordan's idea of a command line switch for the simple
> reason that the 'set nat on|off' *could* be turned on and off at any time
> which would certainly confuse the clients/servers involved.  It seems to
> be you'd want it either on or off for the whole session which the command
> line switch accomplishes well.
> 

I find the 'set nat on|off' a little more flexible.  Say I have two
configurations defined: One for AT&T (which gives me 5 hours a month for
*free*) and one for IBM that's all-you-can-eat.  

Not that this could *actually* happen or anything ;-) but let's say IBM's
local POP is hosed for some reason.  I'd like to be able to `ppp -auto ATT`
(which had `set nat off` in /etc/ppp/ppp.conf) to provide dial-on-demand for
mail queue processing, DNS zone transfers and other administrivia for the
local machine, but prevent the P2P link from being up full-time (or close to)
by the unwashed masses on my local net (who know full well the value of free
access!)

When the hosed IBM POP got squared away, I'd slay the ATT configuration and
load 'ppp -auto IBM' (which, of course, has 'set nat on' in
/etc/ppp/ppp.conf).  Local network nodes would have restored gatewaying to
the world.

Just like I can have different levels of debug, different login scripts,
different LCP params, I think that different modes of NAT should be supported
in the ppp.conf file and, thereby, associated with remote connections rather
than the command line arguments used to start ppp.

I take your point that this could be specified with an -alias argument when
starting ppp, but embedding the setting in the ppp.conf file tends to
consolidate remote-side considerations with per-connection settings, rather
than per-instances of ppp.

Comments?

...sjs...