Strange internet connection problem?

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I have a motorola SB6121 cable modem.

Up until the other day I was using a wireless router hooked up to the cable modem to connect to the internet. I used a ethernet cable to connect my PC to the internet.

However, I stopped using my wireless router and opted to directly connect to my cable modem via ethernet

I have a motorola SB6121 cable modem.

Up until the other day I was using a wireless router hooked up to the cable modem to connect to the internet. I used a ethernet cable to connect my PC to the internet.

However, I stopped using my wireless router and opted to directly connect to my cable modem via ethernet cable. However, now the internet periodically disconnects and I can t fix it until I reboot my PC and restart my cable modem. This happens very frequently (~ once an hour) and is very frustrating to deal with.

I checked the lights on my modem and it showed that the modem was connected to the internet (all the lights were solid as usual). However this does not stop my PC from disconnecting from the internet.

I didn t have this problem when my modem was connected to a wireless router but as of this moment I cannot use one. What should I do? What is wrong?

Best Answer:

Richard: It is possible that your ISP is only assigning your public IP address for a short period (say 1 hour), and the computer is not renewing the IP correctly. Most routers assign IP addresses for much longer periods than this on their private networks, and the router may renew the public IP sufficiently frequently that you don't experience a break of service.

It might be that the ISP is seeing the MAC address of the computer instead of the address of the router, and is deliberately blocking the connection until the PC does a new DHCP request for an address (after it is rebooted).

Rather than rebooting the PC, have you tried unplugging the Ethernet cable for 5 seconds and putting it back again? This should be much quicker than a reboot and means you can leave any programs that are not currently using the Internet running while you unplug and replug. This procedure should request the address again when the Ethernet reconnects. If this does not work, then it suggests that the PC might be objecting to something coming from the modem.

The other alternative is that without the router your PC is much more exposed to attack from the Internet and your connection is being attacked. I have seen suggestions that such a set up can result in a computer being attacked with 10 minutes of such a connection unless it is running a good firewall (not the default one) and a very strong anti-virus program (not Microsoft's default AV programs).

Unless there are strong reasons for not using the router, reinstall it.

I hope this helps.

Other answer:

Richard:
To start with, running a PC directly off a cable modem is SERIOUSLY dangerous. A router is a firewall and prevents lots of things from getting to your computer. Without a router, you are doing what many call running naked. The software firewall is anemic at best. In other words, you can get infected far easier than with a router

You don't have to turn on the WiFi portion of the router. Reconnect it (reboot the modem so the new MAC address takes) and your PC to the Ethernet and see if that works. If it still disconnects, do a virus scan.

Steve:
This might be a carrier issue. I would contact the ISP and let them know about this dropping of the Modem.

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