Internet Connection Problem!
March 6, 2005 10:56 PM   Subscribe

I need help fixing a problem with my internet connection.

First off, I have a cable internet connection from Comcast. The problem is this:

At seemingly random times during regular surfing, downloading, whatever, my cable modem seems to reset (i.e., lights go off and come back on sequentially, as though first being plugged in.) This results in a temporary (30 seconds to a minute) loss of connection. Not much of a problem for surfing, really, but as you might imagine it causes problems for downloading files and playing games. I am at a loss to diagnose or solve the problem.

Relevant information: I doubt the problem is with the actual power source. Everything is plugged into the same power strip. My roommate, who is using a wireless laptop connected to the same router, does not experience the same problem.

I thought maybe it was an IP address problem, and maybe it is, but ipconfig returns a valid IP and MAC address, and as I mentioned I generally have connectivity, not the 'network has no connectivity' errors normally associated with a bad IP address.

Comcast online help (interactive chat) has verified by vaccuous "remote testing" that I am experiencing "2% packet loss." They can send a tech, but I'll be charged if the problem is not with Comcast's specific equipment. I would prefer solve it myself and not have to go through that hassle. Help!
posted by Yelling At Nothing to Technology (16 answers total)
Try running a ($2-3) coax cable splitter from your cable connection, with one plug to the cable modem and the other plug to the television. See if anything happens to the video signal on the television when the modem resets.
posted by AlexReynolds at 11:01 PM on March 6, 2005

Your computer will keep it's IP address, even though the cable modem is powered off (or actually in it's boot sequence).

Is the cable modem actually a wireless router as well? Is this one integrated unit? If so who is the manufacturer? Does the cable company lease the router/modem to you as part of your service, or is it one that you purchased separately?

Most likely, you can log into the router/modem and see if there are any log files to help you determine what is the cause of its reset.
posted by stovenator at 11:02 PM on March 6, 2005

Response by poster: I don't have cable television, but that's a good idea.

The router is a wireless linksys router (the 'blue one,' as I've heard them called.) The modem was given to me by comcast on lease; it's a Motorola.

Frankly, I'm not enough of a techie to read a log file and arrive at the solution based on that. I guess I was hoping that someone would see this and just know what the problem was.
posted by Yelling At Nothing at 11:07 PM on March 6, 2005

I don't have cable television, but that's a good idea.

Neither do I, but I get local channels from the signal.
posted by AlexReynolds at 11:12 PM on March 6, 2005

You can pay comcast a $2 monthly fee for "maintenance service", where they don't charge you extra if it's not your equipment. When I needed the comcast guy to troubleshoot my connection, I signed up for the $2 service, and cancelled it when he was done. He had to do some wiring stuff on the cable jacks. (I'm clueless.)

I definitely recommend having them come out and look at your equipment.
posted by agropyron at 11:14 PM on March 6, 2005

where they don't charge you extra if it's not your equipment.

Ahem.. they don't charge extra if the problem isn't caused by THEIR equipment.
posted by agropyron at 11:15 PM on March 6, 2005

In my experience the cable company can't measure anything that's happening downstream of the modem -- so if they're detecting significant packet loss (and I don't know if 2% is significant), then it's occuring somewhere between them and the modem, inclusive. If you're renting the modem from them and you haven't altered the wiring inside your house, then it should be their problem to fix.

A lot of times the guy who pays the first service call will only have the skills to check your inside lines and replace your cable modem; if that doesn't fix the problem he'll scratch his head and mutter something about scheduling an appointment for an outside line technician; the outside line technician won't require your presence and will therefore be answerable to nobody about even keeping the "appointment," and when you call back to discover what happened, they'll act like they've never heard from you before.
posted by coelecanth at 11:28 PM on March 6, 2005

I have similar problems. An Orion 2000 Cable modem and Charter internet. For some reason, it seems that the combination of bittorrent and web surfing leads to a modem crash. The problem was reduced significantly by capping my upload to 80% of the maximum.
posted by swordfishtrombones at 11:35 PM on March 6, 2005

Response by poster: Gee, that makes me feel better, coelcanth.
posted by Yelling At Nothing at 11:35 PM on March 6, 2005

Okay... so you have both a Linksys Wireless Router, and a Motorola modem.

When the problem occurs, the lights all go off on the modem (and not the router) and then blink back through their bootup sequence, right? But even while this is happening, your rommate's PC still works on the internet? I find that unlikely.

Here's a couple things to try. First, using ipconfig - find out the gateway address for your computer. Assuming its, when the problem occurs, go to a command prompt and type:

ping -t

That will send a ping packet to the router. You can hit ctrl-c to stop the ping. Are you getting request timed out, or are you getting responses?

If you are still getting responses from the router, then the problem is most likely the cable modem. Most cable companies will replace the cable modem for free, so try swapping it out. It might be something different, but it will get you a better idea of where the problem lies.
posted by stovenator at 11:51 PM on March 6, 2005

A lot of times the guy who pays the first service call will only have the skills to check your inside lines and replace your cable modem;

The good news is, a lot of times that will fix the problem. I've found cable modems to be fairly flaky.
posted by agropyron at 11:52 PM on March 6, 2005

Sorry -- I actually was trying to contribute. The point was that if you actually have a line problem you have to be persistent about getting a serious technician out for the second appointment. Don't assume that they'll remember to fix the problem just because the first technician says so as a condition of your letting him leave. (agropyron, I mention this because my experience has been the reverse of yours).

My other suggestion is to simplify: if you're connecting wirelessly to the router, try connecting via a network cable. If that isn't working, try connecting directly to the modem. (If you're going to connect directly to the modem for any length of time, use a firewall program).
posted by coelecanth at 11:59 PM on March 6, 2005

Before doing anything drastic, try swapping out all your cables, both Cat-5 and coaxial, one by one. I had a similar problem last year, except my outages were longer than a minute. Days after beating my head against a wall, and even buying a new router and trying a different modem, it turned out to be 3 foot length of faulty coaxial cable.
posted by kables at 12:00 AM on March 7, 2005

I have solved a similar problem by just exchanging the cable modem at the Comcast office. I replaced a shiny new-looking Motorola that was doing the thing you describe with a busted-looking old RCA that ran like a top for the next year [until we moved and I had to turn it in].
posted by britain at 3:50 AM on March 7, 2005

agropyron [an britain on preview] has a good point - both times i've had cable modems installed recently the original unit has been replaced to fix problems.
posted by andrew cooke at 4:05 AM on March 7, 2005

Response by poster: A week later, and the problem seems to have fixed itself. Who knows.
posted by Yelling At Nothing at 2:12 PM on March 12, 2005

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