Network connectivity problem

[MACY]

I don't know if this is the right place to ask about this, but maybe someone knows what to do. My husband and I have separate computers and separate addresses. Our computers are not networked together. For years we have been connected, at the same time, to the internet via cable modem and a router. Now we are unable to be connected at the same time.Sometimes it's me and sometimes it's him, but never at the same time and we never know who's going to be connected or when. We've called Comcast and they say the modem is working properly and the problem is the router. The technician, who was here for three hours and replaced the modem couldn't help. All the lights on the router are blinking as they should (we've tried two different routers and they SEEM to be working properly). We are both using Windows XP and all was well until last weekend when we were at the Comcast office to exchange our cable box. While we were there, the woman behind the counter said we only needed one IP address and removed the second one she saw there. Since then, we've each had connection, but never at the same time. I am at a loss as to what to do. Should we buy a new router? Should I call Comcast again and cry or scream? Can someone here give me some suggestions?

I received a few answers in other Forum. One suggested that I do this:

After the first PC connects successfully,then try the following on the PC that does not.

Open a command prompt window and enter these two commands in the following order:

1) ipconfig /release
2) ipconfig /renew

I did that and the ip address did not renew and now I have NO ip address and am not able to connect at all. I should have known better than to mess around with that! We're getting a new router today in hopes that it will help. Any more ideas would be appreciated. Thanks so much in advance for your time...

[Marco-D]

It seems that you did not really used the Router as a Router but had two independent external IPs from Comcast. Whether it was Comcast mistake to allow two IPs (or may be it was allowed years ago) it does not matter since it seems that they are Not allowing it any more.

One IP can easily used for multiple computers if your Router is working well and it is configured correctly. Leave the past to rest, start with Fresh approach. Read the Router's manual and reconfigure every thing form scratch. I do not know how Comcast authenticates but in case they use MAC authentication this can help.

[MACY]

Thank you so much, Marco Your answer makes more sense to me than any other I've had. I'll install the new router and go from there and let you know how things worked out. I appreciate your time and kindness.

[Marlon]

You should be able to change the device connected to the Cable Modemby power cycling the modem. If this did not work, there is a configuring issue that Comcast needs to address. The modem has a bridging table that stores the mac address, but if you power cycleit, that should clear. Don't know what modem you have, some might require a reset.

Multiple IPs. You are far better off behind a router.

[MACY]

You should be able to change the device connected to the Cable Modemby power cycling the modem. If this did not work, there is a configuring issue that Comcast needs to address. The modem has a bridging table that stores the mac address, but if you power cycleit, that should clear. Don't know what modem you have, some might require a reset.

Multiple IPs. You are far better off behind a router.

Just wanted to let you know that we are connected and all is well. We bought a NetGear Super-G Wireless Router. While running the software we hit a snag, so we called the support number. The agent was GREAT and got us up and running with no trouble. If it helps you or others to know, Comcast does use MAC authentication. I appreciate your mentioning that and for your trouble