Hooking up with Comcast/cable modem service?
 

I have a small black Comcast cable modem with a "by Scientific Atlantic, Inc" thing on the front (there's no other way to identify this thing). It has a USB and an ethernet connection, and my system is using the ethernet connection part.

I've followed the instructions on astro.umd.edu/~teuben/linux/comcast.html. Even so, none of it works.

I don't have the slightest idea what I'm doing here. I set up DSL to work with Linux, but dhcp has always been an alien and very finicky animal for me... is there any way to get this working??

Thanks!

Oh yeah and I'm using redhat 9

uh hello..can someone please help...?

hello? Is there anyone who uses comcast..?

testing.. does anyone see this?

Linux is incompatible with cable modems and will not connect to them on any service, unfortunately. Especially comcast. Plus it's a security hazard because cable modems are vulnerable to packet sniffing by other users in your neighborhood.

Linux is NOT incompatible with cable modems or Comcast. I know because I use Linux with a cable modem on Comcast.

I can't speak for the modems that plug in directly via USB. However, my modem (an RCA box) has a cable connection come into it and spits out an ethernet connection. I used to simply plug the ethernet cable straight into my linux box, enable DHCP (try using netconfig or your favorite graphical configurator), and - voila - browse the 'net.

Nowadays I plug the output of the modem into an external router and have it serve up IP addresses via DHCP to all the computers in the house.

Either way, the modem should just "act" as a normal DHCP server - the fact that you are on cable is not even seen by Linux. It's just another network device.

Yours,
Conrad Shultz

P.S.- I believe Comcast now requires something called the "installation kit" (a.k.a. a CD-ROM) to get up and running on your own. This does require Windows, but I believe can be run on any computer with an internet connection, not just one on the cable. Also, I have been told that an installer can come by with a laptop and do this for you.

Excuse me, just one thing... how would I use netconfig to start dhcp?

Could you spare me a detailed description on how to do that... please?

Thanks...

I am using Fedora Core 1. I believe the same steps worked in RH9...

From the terminal:

Become root, run "/usr/sbin/netconfig", say that you "would like to set up networking," check "use dynamic IP configuration (BOOTP/DHCP)," finish the configurator (no other setting needed), and restart network services by running "/etc/init.d/network restart". Done!

From X:

As root, run redhat-config-network, select the network card in question (probably eth0), click the "Edit" button, check "Activate device on boot" and "Automatically obtain IP address settings with... DHCP." You can probably leave "Hostname" blank, and check "Obtain DNS information from provider." Save the changes (File-->Save), click the "Deactivate" button, and then the "Activate" button. Done!

Hope this helps.

-Conrad

Interesting... in using /etc/init.d/network restart, it told me:

"Bringing up interface eth0:
Determining IP information for eth0... failed; no link present. Check cable?"

The cable is connected to the cable modem and the cable modem light says it's connected.

How do I get the system to realize the link is present?

BTW I owe you a lot for this, heheh.. thanks in advance!

Check to see if there isnt a problem with the ethernet card located inside of the computer.

Run the network configuration tool with the ethernet cable disconnected and see if it will bring up any information about the ethernet card. If it does come up try restarting the cable modem.

Well there can't be too much of a problem - I can get online on that machine through Windows XP :confused:

can the card be detected in linux? Does linux 'see' the card on startup? (could easily be a compatability issue between linux and the ethernet card.)

Yup, it sees the card on startup. I got ifup eth0 to work... now I just need to see why it can't see the cable modem connection......

Is there some other diagnostic thing I should run? I used dhclient eth0 and I don't understand what it really said...

if your using XP to connect through the internet now run "command prompt" and type "ipconfig" see what your IP address is(ususally the second line). Write it down somewhere and restart in linux. Im not to sure if red hat uses YaST, but if it does find the network card configuration page and use the IP address you wrote down as a static IP in the configuration. Try to see if it works then.


If it doesn't work copy down your "ifconfig" and post it here.

Good advice, NetAX.

If you don't have YaST, netconfig will allow you to do the same. You may also need to find out what DNS servers XP is using (and potentially a Gateway as well), and input them into Linux if you are doing static configuration.

-Conrad

i can help u
 

right no i'm working ion the same problem. the tech support offered me no support, but i assume that your running an operating system other than linux because your able to post here. Anyway, in whatever operating system your using look for your ip settings, assuming that your other conection uses comcast. If you don't have a way to conect to comcast using a different os i can't really help, beacuse we probally live in different place etc. thu the netwrok data will be wrong. I duel boot linux and windows xp so under xp i looked up the details on my internet connection. the info you find SHOULD be enough to conect using linux. Good luck! and if i can evr get my connection running right i'll run a site or somthing for othe comcast-linux users

I recently set up Comcast on another machine, and learned a few things that might help people...

After hooking up the cable modem and plugging it into the ethernet card, I had no network connectivity even though the modem had its Data and Link lights flashing. This is unsurprising, since the modem needs to be "registered" with Comcast.

I happened to have a Windoze XP laptop handy and tried using the "Comcast Self-Install Kit" I obtained from the local office (I had previously arranged to buy service by calling up their 800 number and tacking it onto my cable TV bill). However, for reasons I still don't understand, the software failed to connect to the registration server.

I then called Comcast tech support, read him the message, and - get this - he inadvertantly was helpful AND gave me instructions that would work in Linux!

He directed me to configure "Internet Explorer" (read: Mozilla on Linux) to use sas.r1.attbi.com (perhaps specific to my area) as a proxy server, and connect to it directly. At the server was a web-based configurator which registered my cable modem and got my connection working. No Windoze required!

So, if you are having problems, I suggest calling Comcast tech support, telling them that you need to do the proxied web-based setup of your cable modem service, and you can probably get all the details you need.

Good luck!

-Conrad

Hi, I'm back... went on vacation for a while.

I keep getting this error in Linux:
/sbin/dhclient-script: line 58: need_config: command not found

what the heck???

My Linux can't even see other computers on the lan (behind the router)...

Hi,
I've been emailed many websites about comcast w/linux. I don't have the websites with me, but I will let you know them soon!

I just can't believe it's so incredibly difficult to get Linux to see another system that's peer to it behind a router.

In Windows XP I can do this in 1 minute flat if I count the time to go take a leak. In XP my systems are so well networked I'm burning DVDs on one machine using a program on another!

This is totally not right.

OH yes and my PC IPs are
192.168.0.100
*.101
*.102

and the router is
192.168.0.1

Hi,
Here is my list of websites for comcast with linux. I got this list because the person who gave them to me thought that my problem was because of comcast.

http://my.brandeis.edu/bboard/q-and-...ical%20Support

http://www.comcastusers.org/

http://micha.bloki.com/index.jsp?nam...&folderId=3021

http://www.astro.umd.edu/~teuben/linux/comcast.html

http://help-site.com/LDP/HOWTO/Cable...roduction.html

shoulda mentioned the router sooner. Things are different with a router. Is your router set up for dhcp server to the lan and client to comcast? Or is there no firewall active on it? if the computer can see eth0, can you ping the other computers on the lan? internet?

Don't know what your error message means, but I would take it as something is missing. It can't find the command (or can't find the config file?). I would try reinstalling the dhclient program.

Don't know what the problem is. I use comcast and I plugged in the wire and it had no problems at all getting to the internet. The comcast CD in not necessary, at least not after you made an initial connection. Had it on a windows computer, reinstalled the OS without reinstalling the comcast stuff and have had no problems getting online with either computer. If you can connect with windows from home, I doubt it is the comcast CD.

I'm not sure if it's set up for dhcp server.. how would I know? I'm using a D-Link DI-604 Broadband Ethernet Router.

In Windows I can ping the LAN and the internet, in Linux, nada.

Darn, I always leave out something in my posts. I reinstalled dhclient and dhcpd and several other programs before I posted this. I can't find any reference anywhere to "need_config".

I'll reinstall Linux from scratch and come back and post an ifconfig readout... maybe that'll get rid of the need_config problem.

another thing, with a router and multiple computers, you can see if the router can find your linux box. Read the manual (you can download it) and see how you access its menu - probably by typing the router IP in your browsers address bar. From there, you should be able to check to see what IP allocation the router has for your lan. So, turn on the linux box, and from a different computer, go to the router menu and check if the router sees your linux computer. Oh, and from here you would set up a lan dhcp server, which you have with IPs of 192.168.x.x.

I doubt that your router will see your linux box, you are getting that command not found error. Whenever I ran dhclient on my computer, I never had the -script part of the command, what does that do?

This won't help me, we are getting out of my league, but it may help someone else, what flavor of linux are you using?

Well it seems that installing Fedora Core 2 test 3 (I'm going to get the full DVD version of core 2 in a little while) did the trick.. I can see the Internet from here behind my router. I really wish I knew how the system did this. When I get another linux box up I'm going to go back at setting up a network from scratch. I'd REALLY like to make a web page simplifying this so others don't have to go through the llama stage that I'm going through :(

Now for the next big question, how do I access my other peer computer behind this firewall?

This computer is 192.168.0.101 aka something (I'd like to have it known as foo) running FC2 Test 3
The other comp is 192.168.0.100 aka bar, running Windows XP SP1

How do I give this computer a name that a windows XP machine can find on the workgroup, give the machine named 'bar' permission to browse this machine, and actually browse the windows XP machine with this one?

Thanks... and also thanks for your patience :)

I think you need samba--

Here is what a google linux search turned out
http://www.google.com/linux?sourceid...=utf-8&q=samba

that's the search page

Oh yeah--It says moz client because I am using mozilla

you do need samba to access windows over the network. www.samba.org