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Old 05-06-2004, 06:03 AM   #1
comcastuser
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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!
 
Old 05-06-2004, 06:03 AM   #2
comcastuser
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Oh yeah and I'm using redhat 9
 
Old 05-06-2004, 12:44 PM   #3
comcastuser
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uh hello..can someone please help...?
 
Old 05-06-2004, 05:06 PM   #4
comcastuser
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hello? Is there anyone who uses comcast..?
 
Old 05-07-2004, 12:48 AM   #5
comcastuser
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testing.. does anyone see this?
 
Old 05-07-2004, 01:19 AM   #6
Raveolution
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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.
 
Old 05-07-2004, 01:55 AM   #7
shultzc
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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.
 
Old 05-07-2004, 06:11 PM   #8
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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...
 
Old 05-07-2004, 06:23 PM   #9
shultzc
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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
 
Old 05-07-2004, 10:26 PM   #10
comcastuser
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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!
 
Old 05-07-2004, 10:37 PM   #11
NetAX
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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.
 
Old 05-07-2004, 10:46 PM   #12
comcastuser
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Quote:
Originally posted by NetAX
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
 
Old 05-07-2004, 10:56 PM   #13
NetAX
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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.)
 
Old 05-08-2004, 01:38 AM   #14
comcastuser
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Quote:
Originally posted by NetAX
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...
 
Old 05-08-2004, 10:35 PM   #15
NetAX
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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.
 
  


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