Subject: Re: how do I configure PPP to do this?
To: John F. Woods <jfw@jfwhome.funhouse.com>
From: Ronald Khoo <ronald@demon.net>
List: current-users
Date: 10/23/1997 21:14:01
> The only other way this could be made to work is if NetBSD can be
> configured to support what cisco calls an "unnumbered" network 

I think that actually works.  AFAIR, the way you do this is to give
the ppp interface the *same* ip address as your ethernet interface.

In pictures, what you have at the moment is something like this:

----+                                       +--------------+
ISP +158.152.213.1/30------+158.152.213.2/30+ppp0 BSD  eth0+-193.195.224.1/24
----+                                       +--------------+

We *used* to connect a lot of our customers in this way when we
first started out as an ISP.  Nowadays, it's more usual to do something
like:

----+                                       +--------------+
ISP +158.152.1.222/32------+193.195.224.1/32+ppp0 BSD  eth0+-193.195.224.1/24
----+                                       +--------------+

Note that ppp0 is ifconfig'd to the same address as eth0.  BSD
derived IP stacks have been able to cope with this since long
ago.  It's one of the things that the POINTOPOINT ifflag lends
meaning to.

Anyhow, that way the BSD box just has the one IP address, and
no one will be confused about who it is :-)


The only other way to solve the problem is to add an option to
the application program to bind(2) to the address you want before
connect(2)ing.  That's less convenient :-)

-- 
Ronald Khoo <ronald@demon.net> Voice: +44 181 371 1000 Fax: +44 181 371 1150