April 22, 2019

.comment: Going Broadband With a Cable Modem

Bye-bye Telco

  • September 27, 2000
  • By Dennis E. Powell

When my wife and I moved to our little Connecticut horse farm, we arranged Internet access ahead of time. Oh, yes, the phone company representatives said, you'll have high-speed Internet through snet.net.

Yeah, right.

When we got here, we discovered that the lines were duplexed, meaning not only that we wouldn't regularly connect at more than 26,400 bps, but indeed that a higher connect speed wasn't even possible.

DSL? Sorry, we were too far out in the sticks.

The telephone company kept saying that new copper was being strung, just wait a little longer.

A little longer came to its end last week. While I've always thought of cable modems as a ragingly insecure and laughably nonserious way of getting online, it had become clear that if we wanted to see websites while we still remembered why we'd gone to them, a cable modem was the only choice for us.

So, my friends, begins the saga of the arrival of Charter Pipeline in our home, the problems encountered, and the solutions we chose. I shall not go into great detail about the mistakes made along the way, in part because it's embarrassing (and in some cases really embarrassing), and in part because I hope that this will be useful to others contemplating the same kind of setup.

The Security Issue

Anyone exploring the switch to a cable modem will find a multitude of stories having to do with the lack of security. I do not know if these stories are true, though I was asked to sign a document stating that I expected no security from Charter Pipeline at all, so I suppose there might be something to it.

Now. It is possible to set up a software firewall in Linux, to turn off the multitude of services that distributions maniacally start by default, and to install software designed to prevent cracking and to report it if it has taken place. I have some of that installed (though not a firewall), but as they say in the military, my confidence level was not high--good enough, maybe, for a dialup, but not for a permanent connection.

As it happened, I was going to need to add some hardware anyway: A network card, and a hub, because I wanted to feed a couple of machines, maybe more. My printer has a network connection available. I keep a couple of notebook machines around, and there is always a machine in progress here.

And it happens that you really can't just plug in the cable modem line--a RJ45 connection--to a hub and send it out to everyone.

Fortunately, practically everyone in the network hardware business has now come out with a little box that performs a multitude of functions: firewall, NAT, and so on. These typically allow many machines to be served by the same cable (or DSL) connection. It's plugged in between the cable modem and the hub (or the computer, if only one machine is involved).

I decided to try to get all three--the network card, hub, and firewall box--from the same company, on the simple justification that if I had to phone tech support, it would be more difficult to lay the blame on one of the other suppliers. My choice was D-Link, because their products are inexpensive, because they promise Linux support, and because I was satisfied with their technical support, which I phoned and talked with before I bought anything. Their answers were satisfying. (And no, I am not compensated by them in any way, nor did I receive anything for free.)

After a little additional research, I decided upon their DFE-530TX+ network cards, which seem solid and which one can get for under $20 a pop.

Their website talked of a thing called the DI-704, which combines one of the little firewall-NAT devices with a four-hole hub. Sounded pretty attractive. Problem was, it wasn't yet available. And contemplation led me to realize it would have been pretty minimal anyway: my machine, the printer, my wife's machine--that left only one connection. So I got their DI-701, which is a one-in, one-out device that I'm counting upon to protect my home and office network from the bad guys. It feeds into a separate device, an eight-hole hub, which is then connected to the computers, the printer (which had a JetDirect card in it when I bought it), and so on.

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