Very Computer

I have the follwing problem that I am trying to develop through to a
solution:

A LAN (6 machines) with a 56K modem on a Linux Server. LAN only runs
TCP/IP and all IP's are internet ready.

A Linux Server with 56K modem connected to an internet backbone via a
PCI network card.

The telephone line between the two is/can be dedicated to keep the LAN
connected.

I want to be able to connect the LAN to the internet using this set-up.
A possible addition of firewalls at both servers is later (at the same
time ?) envisaged using TIS.

Can anyone suggest a possible method that already exists or if there are
any guidance notes avaialble for this ?

I'm in the odd position of being able to both control the dial-in and
the dial-out and there doesn't appear to be a HOW-TO that covers all
this.

Regards,

Dominic Baines

First problem is 56k modems can ONLY talk to special isp modems at the far
end. One end of a 56k modem link MUST be digitial, so no luck there.
You could use four modems and 2 phone lines for a 67.2k connection (assuming
you can achive a 33.6 connection on both. Read the file in the source tree
called drivers/net/README.eql and read the ppp howto.

Once you do that set up the computer with the modems as a gateway for the rest
of the computers in the lan and configure the computer on the internet as an
ip forwarder or ip translation depending upon what you need.

Good Luck.

On Fri, 14 Nov 1997 07:43:35 +0000, Dominic Baines

Quote:>The dial-in part of the connection and the IP forwarder set-up has me a
>little
>foxed as it is difficult to locate guidance notes on it. Any PPP HOWTO
>mentions
>dial-in but the section is a little light on information for this type
>of set-up.

Good luck
Erick

Thanks Erick,

Quote:> >The dial-in part of the connection and the IP forwarder set-up has me a
> >little foxed as it is difficult to locate guidance notes on it.
> The IP setup is fairly simple. You need to have IP forwarding turned
> on in the kernal.

Quote:> Then, your LAN has the IP for the PPP link as the
> default gateway, and on the other system, the PPP link to the net is
> set as the default gateway. For incoming packets, make a route with
> the subnet for the LAN with the gateway as the PPP link back to the
> LAN. I think that should work.

LAN (Home)
   |
[NIC(x.y.110.50) ---- PPP (x.y.110.51)]  LAN LINUX SERVER
                                     |
                                 modem
                                     +
                                     + Private telephone line
                                     +
                                 modem
                                     |
                                 [PPP (x.y.110.236) ----NIC (x.y.110.54)]
REMOTE LINUX SERVER
                                                                         |
                                                               NETWORK
(contains 4 servers I control, I do not control the router out of subnet)
                                                                         |
                                                              NETWORK gateway
(x,y,110,99)
                                                                         |
                                                              INTERNET

The LAN (HOME) default gateway will be (x.x.117.51), at the REMOTE LINUX
SERVER I need to set the default gateway to (x,y,110,99) for the normal
network but I need to also set-up a route to (x,y,110,236). And the REMOTE
LINUX SERVER will have to forward incoming packets back through
(x,y,110,236).

Can you advise what the routing table on each machine should look like ? (And
how to create it ?) Or is there a good text on this sort of thing ?

Thanks,

Dominic Baines

I missed the first part of this, but it sounds similar to what we are
going through.

1) Without knowing the model, most 56K modems are only 56K in the
download direction, 33.6 in the upload direction.  So 2 of them on a
public line gets you 33.6 both ways, max. (The 56K side will bump down
to match the 33.6 side).   Assuming you have good enough lines to get
33.6.

2) We've gone the dedicated 56K line route ourselves.  (ISDN is not
available).

3) Made the mistake of ordering 4 wire lines instead of 2 wire.  That
means we can't use modems.  If you order leased lines, you can get
them 2 wire, then use USR Couriers, etal in leased line mode.  Can't
do that with 4 wire lines.   So we have the DSU/CSU's now.

4) Currently have a dumb terminal at the remote site, plugged into the
DTE interface on the DSU.  This end is plugged into a spare port on
our Linux box.  Can login (really fast) on the terminal.

5) Next step is to get PPP running and route the traffice we need.  I
have til Friday.....

Jim Wildman

Jim Wildman
IS Manager
Madison County Hospital