Getting to the Internet through Comcast

Do you have a Comcast high-speed connection to the Internet? If so, are you having difficulties getting to the Internet? (Obviously, if you are, you're not on the computer from which you're having the difficulty. Either that, or you went through a particular connection and you went back to the old connection.)

Here's the typical scenario: You were connected using a particular computer, but you decided to add another system. So, you popped over to Best Buy and bought a router, such as are sold by Linksys or D-Link. Now, you can't get anywhere.

Here's why. First, some background. Every single ethernet connection is required to have a MAC (MAC = media access control) address. The MAC address, typically just called "the MAC", is essentially a serial number for each device. It uniquely defines that particular device. For example, you most likely have an Ethernet connection on your computer. It could either be a NIC (network interface connection) card or a connection that is direct on your motherboard. Either way, this connection has its own MAC address. If you are using a NIC card, such as made by D-Link or any of the others, it will have a MAC address. You can have two of the exact same make & model NIC cards, but they will each have a different MAC address. As I said, each device will have its own, unique MAC address.

The same goes for routers, wireless access points, on and on and on. Each will have its own MAC address.

What does this have to do with you not being able to connect to the Internet through Comcast? Simple. Let's say that your old connection was a PC connected directly to your cable modem. What happened was this: Comcast registered your connecting by using the MAC address of your computer. It's a form of security. If someone else tried to take over your connection, they wouldn't know your MAC address. (Yes, for those technical people out there, it's possible to spoof it. But that requires more work. Hackers tend to be, among other things, lazy.) Remember I said that every device has a different MAC address? Well, when you got that shiny, new router, it also had a MAC address. And it was different than that of your computer. When you plugged it into the cable modem, Comcast did not recognize that new MAC address. Therefore, it essentially locked you out. No Internet for you! (Note: That last sentence was said in the same voice as the "Soup Nazi" from "Seinfeld".)

But fear not! There is hope. You have two options. The first is to clone the MAC address of your old connection to your new router. The other option is to get Comcast to recognize the MAC address of your new router (or whatever new thing is connecting to the cable modem.)

To go with Option #1, use whatever method is necessary to configure your router (or whatever) and look for an option to clone the MAC address. On my Linksys router, for example, I open my Internet browser, open the web-based configuration page (by typing "http://192.168.1.1" into the address bar), then enter the administrator password. From the main "Setup" page, there's an option called "MAC Address Clone". On that page, I select "Enable" next to "MAC Clone Service". At that point, the "Clone" button is no longer greyed out. I press that button and it clones the MAC address of my computer. (NOTE: I don't know how it knows which MAC address to clone if there are multiple items connected to the router. It could be that it simply clones the MAC address of whatever computer is being used to set the configuration settings. Again, I don't know this for sure.) Finally, click the button at the bottom that says, "Save Settings".

From there, you should be able to connect to the Internet.

Option #2 is to simply disconnect your cable modem from the cable connection. You will need to leave it down for at least 12 hours. (Note: I've not tried this. I'm simply quoting what some others have reported.) At that time, Comcast will release your IP address. When you connect back to the Internet, it will allow you to re-register with a new MAC address.

Best of luck to you!

Gajimmy