Changed my MAC Address with a program called Macshift and then I could not connect to the Internet using Comcast Cable?

Posted on 2006-03-29
Medium Priority
Last Modified: 2012-08-14
I changed my MAC Address with a program called Macshift and then I could not connect to the Internet using Comcast Cable?  Can I get reconnected to the internet through Comcast Cable after changing my MAC Address with MacShift?  Could I use the Comcast Cable Self Install Kit to get reconnected after changing the MAC Address?

Question by:gdkinney_2
LVL 97

Accepted Solution

Lee W, MVP earned 400 total points
ID: 16325969
Turn off the cable modem for 1 minute (unplug it).  Then reconnect it.  Cable modems don't take kindly to changes of Mac Address without a reboot.

Assisted Solution

x_X_x_X_x earned 400 total points
ID: 16328342
Not sure about comcast but most cable providers use your mac as a means to authenicate on there network. So you changed the mac address of your broadband modem? If so you will have to call Comcast to hav them register  the new mac address on there side

Assisted Solution

tristancomputes earned 400 total points
ID: 16329962
Comcast (like many other ISPs) lets you access the internet with a specific MAC address.  Once this address is registered in their DHCP server, it will refuse to give you another address (as it is expecting to see your old computer again).  Just call Comcast support and tell them that you switched PC's.  They'll remove the old MAC address from their records and when you reboot everything the new one will be registered with them.

Of course, the alternative to this would be to change back to your old MAC address (because it really shouldn't be necessary to change yours in the first place).  Also, if you are using a router with the Comcast service, you should have the router's external MAC address imitate the one of your originally registered computer.  This will allow you to continually change the computers connected to the internet (through the router) without Comcast ever knowing and cutting you off because of it.
LVL 15

Assisted Solution

Computron earned 400 total points
ID: 16330441
Not to mention that Comcast might not take kindly to it either. They may view that as you trying to find a valid lease to establish a freebie connection. Use caution or change that MAC address back if possible. In the original paperwork when they installed your cable modem, they most likely have a sticker on that sheet that shows your MAC address.

Assisted Solution

csgeekpyro earned 400 total points
ID: 16384757
I used to have comcast (I have cox now that I've moved) but they don't use your PC's mac to authenticate to the UBR, they use the cable modem's Coax interface MAC address.  That's the only one they actually "register".

The problem is likely with the modem.  When the model is provisioned for 1 computer connection, it won't offer IP's or talk to any others.  You need to make the modem forget about your MAC address.  The easiest way is to unplug it for a few seconds, but if that doesn't work, navigate to its config page (usually at and find the button/link for factory reset.  That'll do it.

Featured Post

What does it mean to be "Always On"?

Is your cloud always on? With an Always On cloud you won't have to worry about downtime for maintenance or software application code updates, ensuring that your bottom line isn't affected.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

    Over the past few years, small business and home owners have become so dependent on internet that a need for redundancy has arisen.    What happens when your small business or home / home office loses its internet connection?  The results c…
Sometimes you have to pull out old tricks to get a new firewall to work… While we were installing a new Sonicwall at a customers site we found that sites they were able to visit before were not working.  It seemed random and we could not understa…
Despite its rising prevalence in the business world, "the cloud" is still misunderstood. Some companies still believe common misconceptions about lack of security in cloud solutions and many misuses of cloud storage options still occur every day. …
As many of you are aware about Scanpst.exe utility which is owned by Microsoft itself to repair inaccessible or damaged PST files, but the question is do you really think Scanpst.exe is capable to repair all sorts of PST related corruption issues?
Suggested Courses

850 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question