asked on

losing connection with comcast cable modem

OK, I have a brand new dell PC with Windows XP. The problem is: every time that I shut down the PC- turn it off, i lose my internet connection and/or the connection with the router.

After powering the PC up, I have to then power cycle my cable modem in order to make it work. I am going thru a Linksys VPN router. I actually replaced the router, thinking that this was the problem. But, I am still having the issue. Is there something wrong with Comcast or I am I missing a configuration setting. Does MAC Cloning have anything to do with this? Ugh!!

Thanks in advance...

JLB

ASKER CERTIFIED SOLUTION

Focusyn

membership

This solution is only available to members.

To access this solution, you must be a member of Experts Exchange.

Start Free Trial

Caseybea

If this isn't the MAC issue noted above, it also sounds like a DHCP-related issue to me. To test this theory, in the network-TCP/IP properties, configure your PC with a STATIC (fixed) network address, instead of using DHCP. The network you are using internally is most likely 192.168.0.x, so you could turn OFF the DHCP server in the linksys, and hardcode the network address on the XP box.

(Note: Regardless of whether or not this fixes your issue, it DOES speed up the XP boot/login process quite a bit....)

jameslbrady

ASKER

So, do I need MAC Filtering? But, if I changed out my pc and my router, do I need to call Comcast so that they can update my new MAC address? Could this be an issue? Also, is there a setting somewhere that could time out the router or the actual cable modem?

JLB

Focusyn

You don't need to call them unless you change your cable modem. Comcast has the MAC adress of your modem; that's how they activate/deactivate your internet service. The MAC they use for your DHCP lease is the MAC of the machine connecting thorugh the modem. That's why I asked about bridging versus routing. If your Linksys is in Routing mode, then Comcast is assigning the IP address to your router by its MAC. I'm wondering if your Linksys may have some feature that's switching it between bridge/route when it detects only one computer connected. That would be an easy explanation of the "issue" I've been advised of by their geniuses in tech support. At any rate, when you connect any device (PC, router etc) to the cable modem, and that device requests an IP address, then Comcast sends one based on the MAC address of said device. As long as it sees that device connected, it will not re-issue any more addresses through your cable modem. Once a device obtains an address, Comcast's DHCP table shows one address leased to a specific MAC through your cable modem, and will assign no more. It has a timeout limit and does not constantly poll your modem.

Now, once a device is on there, and you want another one on, only two things will clear the lease in their table - first, is to wait for the original lease to time out, second is to reset your cable modem, at which time your cable modem reports the current device connected (or most importantly reports that the device to which the IP is/was leased is no longer connected) and Comcast assigns the IP address once again.

Neither your cable modem nor your router should time out their connection unless there is a configuration problem such as I had, where they provisioned the wrong model. Under those circumstances, mine timed out a few times a day as they did not recieve the expected successful TFTP response from my modem, and their system would kill my connection and start over again with trying to configure my modem.