[Q] Newbie PPP dial up problem

[Donovan J. Edye]

Shane,

Thanks for the pointer, but the other problem I have is that I cannot seem
to get traffic that is on eth0 to go out the ppp0 port. Not sure that NAT
addresses that.

--D


 -----Original Message-----
From: 	Shane Huntley [mailto:huntleyse at iname.com]
Sent:	Sunday, 7 October 2001 19:44
To:	Donovan J. Edye
Cc:	linux at lists.samba.org
Subject:	Re: [Q] Newbie PPP dial up problem

What you are trying to do isn't so simple.  The problem is that packets
from your hosts in the 192.168.xxx.xxx be routed on the internet as they
aren't valid addresses outside local LAN's / private networks.  To talk
on the internet the host needs to have or appear to have a valid IP
address so the remote webserver can address the reply.

There are two solutions to the problem:

 Network Address Translation (NAT) wunning on your gateway computer will
relable packets going out with it's valid internet IP address allocated
to the ppp0 interface and redirect the replies.

http://netfilter.samba.org/unreliable-guides/NAT-HOWTO/NAT-HOWTO.linuxdoc.ht
ml
gives a guide for the 2.4 Kernel or a google search for "NAT LINUX" will
turn up heaps more info.  IP-Masquerading is another term for this.

The other possible way of getting around this would be to set up your
gateway machine as a web proxy using something like SQUID.

Personally I have cheated and have a dedicated box running "smoothwall"
as my gateway machine "www.smoothwall.org" which takes care of just
about everything straight out the box.

Shane


Donovan J. Edye wrote:

>G'Day All,
>
>What I want to do is so simple I cannot figure out why I cannot get it
done.
>I have a gateway box 192.168.40.1. Attached to that I have a modem. I would
>like the rest of the network 192.168.40/24 to use the .1 box to access the
>net. I have set up the dial up info using pppconfig, but the routing does
>not appear to work. I can ping the 192.168.40.1 box from another machine on
>the network say 192.168.40.10 but when I tracert to say www.hp.com
><http://www.hp.com>  from the 192.168.40.10 box I do not seem to go out the
>ppp0 link. I have no firewalling whatsoever in place. Can someone please
>point me in the direction of a FAQ / HOWTO that shows how to set up a LAN /
>Dialup configuration such as the above?
>
>--D
>