[Q] Newbie PPP dial up problem

[Donovan J. Edye]

G'Day,

Just to clear this up. I am connecting a home network to our internal
network at the office:

Home: 192.168.40/24
Work: 192.168.42/24

I have no need to do NAT to connect these two private networks. What I did
need however was to allow packets to travel between my interfaces ie eth0 ->
ppp0 on my dial up box. As Martijn pointed out I needed to do echo 1 >
/proc/sys/net/ipv4/ip_forward to enable forwarding. A "better" solution
under Debian is to modify the /etc/network/interfaces to enable ip
forwarding. Once I did that I was able to get the packets off the network
going out the ppp link. Once on our internal network we can do the necessary
NAT to get me out into the big bad world.

Thanks to all for their suggestions and input.

--D

 -----Original Message-----
From: 	linux-admin at lists.samba.org [mailto:linux-admin at lists.samba.org]  On
Behalf Of jeremy at itassist.net.au
Sent:	Sunday, 7 October 2001 23:51
To:	resolve at repose.cx
Cc:	d.edye at bigfoot.com; linux at lists.samba.org
Subject:	Re: [Q] Newbie PPP dial up problem

 << File: ATT00248.dat >>
> will that help in this case, jeremy? he's said that he's connecting to
> another private network.
>
> donovan, say your layout is like this:
>
>
>  net1: {host_a, host_b} <-> net1_gateway
>         <-------> net2_gateway <-> net2 {host_c, host_d}
>
> you'll need routing rules so that the hosts in net2 know how to reach
> net1 (tell them the default gw is net2_gateway), and you'll need the
> associated rules so that net1 hosts know how to reach net2 hosts.
> otherwise you'll be able to send data to them, and they won't know
> where to reply.
>
> if this is the sort of arrangement you're using, you don't need IP
> forwarding, masquerading, or anything else. you just need to tell the
> hosts they can access the other hosts via the gateway.
>
> cheers!

Damien,
  very true, and I can't see his diagram (ms-what?) to get the full
picture, but it does sound like his border machine is connected fine. If
this is the case then he could fake it by masquerading so that all
connections appear to come from the border machine.  This is a poor
solution, but would work if he is only initiating connections from his
subnet.

If he really wants to properly connect the two subnets then he may wish
to consider a bridge, rather than tinkering with routing.  Like you say,
he would have to tinker with the routing tables for every computer on
the remote net.  That is unless the default route on the computers is to
the localnet then it might work without having to mangle the tables on
all machines.

Tunnelling may be one form of 'bridging' worth considering.

Anyways, I got to get back to work.  Does anyone know why n is even and
k=n/2 if C is a binary linear [n,k] code?   Arrrgh.

--
I/O, I/O,
It's off to disk I go,
A bit or byte to read or write,
I/O, I/O, I/O...