Help determine cause of my Internet shut-outs.

March 1, 2008 10:24 PM

Help determine cause of my Internet shut-outs.

Ok, in order for you guys to try to figure out why my Internet connection goes down, I'll write up the details of the situation below.

I gut shut out of the Internet today because from about 6pm to 1 am in the morning, my cable model would only send packets but not receive them. Windows troubleshooting diagnosed this as a DNS problem. I would do multiple resets of router and cable modem, as well as plug in the cable modem directly to the computer with the router turned off. Each time I unplugged in and replugged in the modem, I would also sometimes reboot the computer. Nothing helped. Then the Internet connection came back on its own. Now, I am in the Boston area and using Comcast, and I had their tech support come over and check out the problem once, however this didn't do much. By the time the technician would come over, the connection was already back up and he couldn't detect anything dysfunctional. Unfortunately, these down times happen every so often, so I am still frustrated.

To sum it up, what do you think the problem is? Is it a Windows bug or is it the cable modem? Perhaps it is the cable wiring within my home that is at fault. (It can't be the cable service in general, since when I called support, their network was fine and I was the only one to complain.) Btw the model of my cable modem is Motorola SB4200, while the router's is DLInk 614+

posted by gregb1007 to computers & internet (12 comments total)

Uhh... error in title. It should say: Help me determine the cause of my Internet shut-outs.
posted by gregb1007 at 10:25 PM on March 1, 2008

Have you considered that your modem is busted? I had to replace my SB a few years ago after a power outage. All the lights were blinking and everything, but it didn't want to "connect" to the internet. I bought a new modem, called up Comcast and I was back online in an hour or so.
posted by pete0r at 10:34 PM on March 1, 2008

Oh yeah, forgot a detail... when it wasn't working only three lights were blinking: power, receive, and send. The other ones.. online and activity were off during the downtime though they are usually on. But this is not consistent, sometimes all the lights are on during a downtime.
posted by gregb1007 at 10:40 PM on March 1, 2008

I am having a remarkably similar problem. I'm with Comcast, SB4100 model modem and live on the NH seacoast. My problem started Thursday night, no connection or very intermittent. Not the router, firewall, cabling or PCs. I called Comcast and the tech could see the modem but not get a response from it. OK, modem blown, I'll get a new one. For the heck of it I unplugged the modem for a few hours, plugged it back in a now it works, sort of. The connection doesn't like to send anything.

I think I'll replace the modem on Monday.
posted by D_I at 10:52 PM on March 1, 2008

D_I, keep me updated on how your problem gets resolved/dealt with, thanks for posting ;-)
posted by gregb1007 at 11:00 PM on March 1, 2008

Yeah I live in the Boston area too and use Comcast and this happens to me a lot. I just unplug the modem for about 10 minutes and restart my computer then plug the modem back in and it usually happens. Some times just flipping the WiFi switch on and off on my laptop will help too. But I can relate to your frustration.
posted by lilkeith07 at 12:41 AM on March 2, 2008

lilkeith, interesting to see that these blackouts happen to you as well, but you do seem to recover pretty quickly. Maybe I should unplug my modem for longer. So far, I've only unplugged it for a minute or two to reset: perhaps shutting it off for 10-20 minutes might be more effective. Still, a pretty weird bug, ey? Especially since no one seems to know what exactly's causing it.
posted by gregb1007 at 12:46 AM on March 2, 2008

I had a similar problem once. It actually turned to be a problem with the cable to my house. It took a few tries to get Comcast to fix it (they'd always come over right when things were working!)
posted by trig at 2:19 AM on March 2, 2008

Are you downloading or using torrents? If so I have had this problem consistently with Comcast and it is often talked about on the nets. If you are using torrents activate encryption on your client and you will likely deal with less interruption. Otherwise good luck with CumQuat service.
posted by Odinhead at 2:31 AM on March 2, 2008

Do you have a "suspend" button on your cable modem? Hit it and wait a few moments. Check your connectivity then. If that doesn't work, reboot the router, and try again. If that doesn't work, refresh your computer's DNS (go to cmd, ipconfig /renew ). And if all that doesn't work, hit that suspend button on your modem again, try all the above one more time, and then call your cable provider and make them fix their shit.

I know this because I hit the "suspend" button on my parents' cable modem when I was over one day. I could not, for the life of me, figure out why there was a "DNS" error even though the cable modem's web page said they had valid DNS servers, and so did the router.
posted by Xoder at 6:14 AM on March 2, 2008

Does your cable modem have a button that will turn off the internet? This "feature" can cause the most difficult problems to diagnose, and it's often easy to bump while moving the modem.
posted by odinsdream at 8:58 AM on March 2, 2008

Update: Used the existing modem until Monday, I could connect but upload nothing. Just replaced it with an SB5101 and it would not connect. Did the usual troubleshooting, by-passed router, ipconfig /release /renew, killed the firewall and Kaspersky,modem resets and PC reboots. I finally called Comcast and they connected to it but said there was an error on their end, they did what they do and now its running fine.

I'm guessing I didn't need to replace the original modem and that the first tech I talked to missed whatever error was on their side. Not that I am complaining, I've done tech support and missed plenty of things before.
posted by D_I at 3:43 PM on March 4, 2008