Solution for Comcast users with routers losing net access

Several months ago Comcast took over my cable modem service from ATTBI. Ever since then, I’ve been randomly punted from my Internet connection with either my Linksys lan or wireless router, and also my Netgear routers. The connection could not be re-established until the router was reset.

After months of haggling, I think I have finally discovered the problem. I first read on Broadband Reports that some attbi customers were being assigned the same IP addresses. This bit of info made sense to me, as it explained why I would randomly get the boot and why I could get back on after a router reset. I did not know the solution however.

Then on 9/24 I purchased a Motorola SB5100 cable modem to replace the Toshiba PCX2200 I had bought the week prior as I did not like the Toshiba’s slow 10baseT, half duplex WAN port. I called Comcast to have the MAC address provisioned, and the gentleman told me I could not, but rather I had to use the SAS registration system. After explaining I had my Toshiba MAC provisioned, he did not budge and asked me to log in.

Being on a Mac, he told me to plug the Mac directly into the cable modem and go to Oregon’s SAS server, IE could not find it, so he put me up to level 2 support. While on hold, I found out from a graphic I downloaded off of that I needed Dumb IE, But it got me to level 2 support, so I was happy heh. I was now able to get to the login screen, but I did not have my account ID nor registration code.

The level 2 support guy told me that Comcast is indeed getting more picky about how it hands out IP addresses, and none of my equipment was registered with Comcast! Not knowing that I needed to do this, he cleared out the three MAC addresses registered, gave me my account and registration information and let me log in.

I then was registered, we reset the cable modem and I was surfing.

Then he had me plug in the Netgear WGR614 wireless router, plug the Mac back into the router and reload the SAS server page. Sure enough, it said the router was not registered. So I had two options. Replace the MAC address on the registration with that of the router, or use the Netgear’s cool “Use this Computer” option on the Basic Settings router setup page to clone the Mac’s MAC address into the Netgear. I chose to clone the address and once the router reset, loading the SAS server page showed me as registered.

This was on Wednesday, 9/24 at 11:30 am, I wrote this piece at 6pm on Wed (still running and it was posted on 9/26, 50 hours later. I believe this solved my common drops.


Comcast is giving out IPs to any device that requests them, such as a router. My theory is that if that device is not registered, then the IP is not reserved and can later be handed out to another customer. This of course changes the route tables at Comcast and you are effectively “off the net.” If you reset your router, you either get a new IP, or pull the same old one, effectively bumping the other customer off the net.

I have no hard data to back this up – But since we got the MAC address of my equipment properly registered, it has worked fine.

Here is the graphic that I got off containing the SAS regions and server names. If you are an ex-ATTBI customer and are having connection issues, give this a shot. If you log into your SAS server and it says you are not registered, it could be the source of your woes. Call Comcast and get your equipment registered.


  1. Hi,

    I have the same problem at my friends’ after the switch from ATTBI to Comcast. After they have had a ‘technician’ coming to re-install another cable line, he hooked the computer directly to the cable, didn’t bother about router, etc.

    That way Comcast ‘registered’ the MAC automatically and the router didn’t work anymore.

    After implementing the other MAC address in the router, all works smooth again.

    To make things a little bit more complicated, we are using LINUX on an old computer as router. All services fit on a floppy disk and it works just great.


  2. i got a simler prob but i cant get my router to work at all with comcast i switched from charter to them cuase there now offering 3.2 dwn and 3.0 up here twice as fast as charter but my router will not work at all with there new modems terayon tj715x all the lights blink and ever thing seems as though its working but it dont i get a no connection in the router it cant reach the net at all i tryed many diffrent cable setup and cables just to make sure i didnt have a bad cable some place also cloned the mac add from the modem into the router all i get is a light saying computer is connected to the modem ..

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