[lug] DSL question

[PC Drew]

Thus spake Justin on Saturday, April 22, 2000, 7:42:28 PM:

J> Hi, I finally got DSL available in my area and have it setup to start on the
J> 2nd of the month. I have service with Uswest and I am using a Cisco 675
J> external modem. My isp uses the PPP mode with DSL, how does that work exactly?

That's just the way your DSL router talks to US West's DSL network.
Also, it's a DSL router not a DSL modem.  With a DSL router you can do
a lot more (i.e. setup filtering, setup port forwarding, use with
multiple machines, etc.).

J> I've had cable modem in the past with a static ip and basically just connected
J> that via ethernet to my redhat box. I am going to get a static ip with the DSL
J> too and was hoping to do just the same thing. Does the PPP mode change
J> anything or is that just specific to the Cisco modem? I would think with a
J> static ip and my isp dns info that I could simply configure an ethernet
J> interface to connect with. Any help or suggestions is much appreciated.

Actually, no. You plug the DSL router into a hub or switch and start
NAT on the router.  Then, you setup each one of your machines to have
a gateway of 10.0.0.1 and start giving out IP addresses after that one
(i.e. 10.0.0.2, 10.0.0.3, etc).  If you don't want to do that, you can
start the DHCP service on the DSL router and each machine will
configure its own IP address.

Now what you've got is a whole network of computers masquerading as
one IP address when it goes out through your DSL router.  Using NAT
(Network Address Translation), your non-routable IP address of
10.0.0.2 gets translated to something like: 12.13.14.15:32402
(assuming 12.13.14.15 is your IP address, then the 32402 is a random
port number) and then everything works fine.