[NTLUG:Discuss] ADSL Configuration Questions

[Dan Carlson]

I am in the process of getting an ADSL line from GTE with DirectLink as the
ISP.  I have received the hardware package from GTE and the configuration
info email from DirectLink.  GTE is not scheduled to turn service on until
3/9.

I am trying to understand as much of the configuration process as I can in
advance so that I can get up and running as quickly as possible once GTE
turns service on.

I run Linux on the internet server / gateway for my home network.  While I
am not an expert, I am reasonably experienced at configuring Linux networks,
interfaces, routing, etc.  If I were an expert, I wouldn't have to ask these
questions! :)

My main question is: How do I configure Linux to use the Fujitsu/Orckit ADSL
modem as its internet gateway?  This modem is an external box that plugs
into the phone line and into a 10baseT ethernet connection.

This is probably easy and no big deal, but at this point I don't understand
all the details and options involved.  I am guessing that several members of
this list have already been through the process and can offer some insight.

I currently have two ethernet adapters in my server supporting 100baseT and
10baseT subnets.  I route between them and I use an automated PPP dialup
script and IP masquerading to provide internet access to the clients on the
two subnets.  This all works great.

Can I put the ADSL modem on the existing 10baseT subnet, or do I need to add
another 10baseT interface and dedicate it to the modem?  I think I
understand how to do the latter, but I don't understand how to do the
former.  Does the interface the modem is connected to need to be dedicated
to the gateway function, or can it also be on a local subnet?

DirectLink has provided me with my gateway address and my static IP address.
To connect the modem to a dedicated interface I think I just need to assign
the interface the static IP address and set it up to route to DirectLink's
gateway address, correct?  But how would connecting the modem to an
interface that is also on a local subnet work?  I understand how to assign
an interface multiple addresses, but how would the routing be set up?

Separate question: Is there any protocol running above IP over the ADSL
link, such as PPP?

Any insight that can be offered into these questions will be appreciated.

Thanks,

Dan Carlson
dmcarlson at prodigy.net