Help Needed with Comcast Cable Internet Setup

[Farmer]

Hi all, been a while since I've posted on Anandtech, but I have a question:

I'm home for a week for break and I want to set up cable internet for my folks. We've been on 768 Kbps ADSL (first through Ameritech and, in the past few years, AT&T) for 7 or 8 years now, and we're ready to move on to something faster. I called up Comcast and ordered their 12Mbps service. We have coax wired to our apartment for cable TV, so we don't have to worry about that.

The issue is, I'm leaving on Saturday, and my folks don't know how to nor do they want to set up the service themselves. I've purchased a slightly used Motorola modem from Amazon which will get here today, but I'm not sure when the Comcast "set-up kit" will get here.

My question is, from people who have done it, do I really need the "set-up kit" to setup service? From what I've seen, the setup kit consists of nothing more than coax/USB/ethernet cables, a coax splitter, and a PCI Ethernet card. The first two I can get at Radio Shack, the last one I don't need.

Is there some critical information in the setup kit that I need to initiate service? Like a phone number to call and an activation code, or a username and password? I will also be using a fairly old router with the cable modem (a circa 2003 Netgear wifi router). When I had ADSL, there was a username and password I inputted into the router in order for it to authenticate and get access to the internet. Is there something similar with cable?

The actual physical installed is straightforward (co-ax into modem, ethernet or USB from modem to router or PC) and I don't believe I need help with that, but any info the necessary procedure after hardware installation would be very helpful.

Thanks for reading.

P.S.: What happened to the laughing man avatar?!

 

[nboy22]

Ok, what you're going to want to do is probably use ethernet (because the CD probably has a driver for USB.) Ethernet will be more simple, and will cause less pain to set up.

I am thinking you might have problems with the modem though. The reason being is that sometimes cable providers really lock down the modems to their system and the modems are identified in the system by either a serial number, or mac address (just a number usually printed on the bottom of the modem.

Now if I were you, I'd call comcast and make sure that your modem you purchased online will actually work by just plugging it in. They may either need to program the mac address into their system, or serial number into their system. It is also possible that they won't even do that for you, you'll just have to see.

My experience comes from Cox communications. One time I sold my modem to someone else on craigslist and we both had to call about 2-3 times to release the modem from my old account, and then link it up with the other guy's new account.

As far as the router goes, just make sure you clear out that PPPoE username and password by holding the reset button on the router for a good 15 seconds or so, and you should be golden.

 

[Farmer]

Thanks for the reply. Luckily, I've successfully registered the modem I purchased with Comcast and I'm using the Comcast service to type this post as we speak. I also registered this computers MAC address and Comcast gives me an IP and I can access the internet fine if I hook up the modem directly to this computer. It's fast, much faster than DSL.

However, trying to use the router is a different story. The router is an old one (Netgear FWG114P), but I don't think that should matter much if at all. I've turned off the PPPoE stuff for DSL. I've set the router to use this computer's MAC address. I've specified the DNS servers for my router to use (going off of info from ipconfig when I'm directly connected). I've turned NAT on, so externally, I figure Comcast sees a device with the registered MAC address accessing the correct DNS servers. However, it just doesn't work. They don't give my router a WAN IP address.

Any tips?

 

[nboy22]

Did you get a static IP setup from comcast? I don't even know if they offer it, but you really shouldn't even have to program the MAC address settings OR the DNS issues. Sometimes there are DNS Issues, and it shouldn't hurt having those settings manually typed out if they are correct, but I would suggest just factory resetting the netgear and testing the connection out that way first.

Just take the ethernet and run it from the back of the modem to the router's WAN port, and connect the computer via the LAN port. Your netgear router would normally obtain IP, DNS, and all other settings it needs directly from the modem by itself.

You may also want to try to upgrade the router's firmware by flashing it if possible. Firmware can be obtained from netgear's website.

 

[Farmer]

Nope I did not buy a static IP. Everything should be dynamic, but the if I set the router to detect everything automatically, it just doesn't work. I've done a few resets and reboots of the router to no avail.

The reason I wanted to set the MAC address is I think Comcast will only give you an IP address if your device has a registered MAC address. Why do I think that? Well, when I plug my laptop into the same modem, I can't get an IP. If I plug it into the desktop I did the activation and registration on, everything works fine.

I'll flash the firmware on the router, maybe that will fix it.

Thanks for your help. I'll keep posting updates. I think I'll give Comcast a call tomorrow to see if they can do anything.

 

[nboy22]

Ok, you're correct then, everything should be really automatic. I find it VERY strange that you plug your laptop in directly to the modem via ethernet and you don't get a connection. I have never had that particular problem with a cable modem, except when the ethernet cord was at fault.

So then maybe you could examine your settings on the desktop a bit further. We need to find out what makes it different from your laptop. Maybe you could run that same set up CD (not sure if it can be ran twice) on the laptop and then see if the internet works as a next step

Also, another thought, the router usually takes a mac address from the computer and uses it (I think). Your router should also default to your computer's MAC address if it's the only device connected. So this is why your cable modem should work with any device that's plugged in directly to it by ethernet. The modem should also find a mac address somehow. Is the modem old by any chance? Not sure if that would have anything to do with it, but I've had cable modem for the majority of the past 9 years and have not experienced this same problem you're having.

 

[Farmer]

The issue actually was resolved just now. I had to "power cycle" the modem, meaning turn it off for about 5 minutes and then turn it on again.

Apparently, either due to something with Comcast or the DOCSIS standard, the modem only assigns a WAN IP to 1 MAC address on record. Before, when I did a quick reboot of the modem and just plugged in the router, for whatever reason it did not recognize the router despite the fact I spoofed the MAC. With the "power cycle", the modem loses memory of the attached MAC, and when I rebooted everything in the modem -> router -> PC configuration, everything DHCP'd up fine with the router..

Everything works fine now. In fact I'm using the Comcast service through the wireless router to type this post.

Thank you very much nboy! Your help has been invaluable.

 

[nboy22]

Awesome! Glad I could help resolve your issue. Ah, the wonders of DHCP 😀