Monday, January 7, 2008

Cable Modem Troubleshooting

Recently, I had problems with my cable modem. Due to my knowledge in the area of networking, the first thing I thought was that the network needed to be reset. I unplugged the modem and the router, and then plugged them back in after having them powered down for about thirty seconds. This reset it. That didn't fix my problem. So, my next step was to call my Internet Service Provider. I asked them to reset the modem. (This led to one of the funniest conversations I've had in my life; if I followed the advice of the ISP's tech, I would always think my Windows XP computer was infected with spyware because the tech (lets call him Bill) insisted that "svchost.exe" in the process list was spyware. Then, after I connected my Mac, running OS X, directly to the modem and the connection was still slow, Bill said my Mac was also infected with spyware . This was news to me since I hadn't installed any and there's no known spyware for the Mac in the wild. But I needed to get rid of all those svchost.exe files that were running. Needless to say, I didn't listen to Bill very much longer and soon hung up.) Thanks to Bill's wonderful advice and lack of any knowledge whatsoever, I had to call back and talk to someone else for them to send a reset signal to my modem. That didn't fix the problem either. By this time, I've gone and connected my computer (a Macbook Pro)[already mentioned] directly to the modem so that I can rule out the router as being an issue. Funny thing is, when having my ISP test the connection speeds, the speeds were fine with nothing connected to the modem, but once a computer was connected, the speeds dropped to a horrible crawl. I decided to replace the modem and well, that fixed it. But how did I come to this conclusion? Well, I'm going to provide some of my troubleshooting steps to everyone out there now. 

Step One: You've noticed that your connection is slow, even "speed tests" (though not always accurate) show that your connection is slow. (I use speedtest.net for mine) You can open your command line (In Windows, click on Start then click on Run and type "cmd" (without the quotes) then press the Enter key. From here you can type "ping google.com" (again without quotes) and press Enter. For people on a Mac, go into your Applications folder, Utilities, Terminal, and type "ping -c 4 google.com" the -c 4 will only let it ping 4 times, instead of infinite.)  Most people should have an average of 50ms in the reply time for a cable connection. 

Now you know there's a problem with the connection; ping times are high. Well, the next thing to check is that if your computer is the problem. If you're on Windows, shut down the computer and when you turn it on tap the F8 key until you get the Windows boot Options menu. From here you can select Safe Mode with Networking and see if your connection is any faster. If it’s not, chances are it’s not your computer. If you're on Linux or a Mac, shut down all the programs you're running and try the tests in step one again. If you don't have problems in Safe Mode or with no programs running, you might need to clean your system of viruses or gray-ware (malware, spyware, adware, etc). 

Step Two: Now you know it’s not your computer. Well it’s time to unplug the modem and the router and leave them turned off for about 30 seconds, then plug them back in. This resets both of them. Now run the tests in Step One again and see what happens. Still having problems?

Step Three: Plug the computer directly into the modem. ONLY DO THIS IF YOU HAVE A FIREWALL ON YOUR COMPUTER!!! (In Windows go into the Control Panel and the Security Center and turn the firewall on. On a Mac the firewall is in System Preferences, either under Sharing or Security.) Now, with the computer plugged directly into the modem, run the tests in Step One again. If you still have a problem, now is the time to call your ISP.

Step Four: When you get the tech on the line politely explain what you have done before calling. Tell the tech that you are going to disconnect your computer from the modem and ask him/her to ping the modem without anything connected to it. Then, after that's done, connect your computer and ask them to ping it again. Chances are if the ping is fast with nothing connected and slow with a computer connected, then the modem has gone bad. If you rented the modem from the ISP, ask the tech if he can send out a new one. If you bought your modem, thank the tech for the work he did and then go purchase a new modem. (If it doesn't work you can usually return it.) 

Step Five: Replacing the modem didn't work? Time to call your ISP again and schedule a tech to come and check the cables. By this point, you've ruled out everything else that could be a problem. The good news is that you've ruled everything else out. The bad news is that you have to wait for someone else to come out and test things to fix it.