# Why does my cable modem randomly stop working? **URL:** \ **Category:** Factual Questions\ **Created:** [January 12, 2003, 1:46am UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060 "2003-01-12T01:46:11Z")\ **Posts on this page:** 12\ **Page:** 1
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [January 12, 2003, 1:46am UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/1 "2003-01-12T01:46:11Z")
I have Road Runner with 2 PCs plugged into a Belkin router which goes into a cable modem. Everything usually runs perfectly, but once a day or so I’ll be browsing the internet and the connection will just stop working - it’s never anything I do specifically, sometimes it’s as basic as browsing the SDMB. I usually have to unplug the modem a few times to reset it, reset the router, and reset the computer. It also occasionally cuts off when one computer is online and the 2nd is turned on. Any ideas? ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [January 12, 2003, 1:50am UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/2 "2003-01-12T01:50:42Z")
OK, here’s a thought - do you have dynamic IPs? When I was on dynamic IPs, when they expired the IP and renewed it, it would sometimes disconnect me until I cycled power on everything. Then I got a Linksys, and it somehow magically fixed it by refreshing the IP better than the PC did. In fact, beforehand I could manually release and renew the IP, and the damn thing still wouldn’t work until I cycled power on everything. Could another thing be overheating? Some people have reported cable modems being “flaky” due to overheating from time to time. ---
**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\ **Post date:** [January 12, 2003, 2:06am UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/3 "2003-01-12T02:06:10Z")
I’m not sure why this happens, but it happens to me too. In my case the following (from a Command Prompt) usually does the trick, without power cycling the modem: ipconfig /release ipconfig /flushdns ipconfig /renew ---
**Author:** ![Bob55](https://avatars.discourse-cdn.com/v4/letter/b/e9c0ed/32.png) [@Bob55](https://boards.straightdope.com/u/Bob55)\ **Post date:** [January 12, 2003, 2:10am UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/4 "2003-01-12T02:10:13Z")
Overheating is a possibility, but the fact that it happens when the 2nd computer turns on and starts to use the network makes me think it’s something with IPs…but it does it randomly even when just 1 computer is on. As far as IPs go, I assume mine is dynamic but I thought once I had one it stayed with that IP until I reset the Cable Modem. Also, are IPs controlled by the router? Any way to fix this? ---
**Author:** ![DarrenS](https://avatars.discourse-cdn.com/v4/letter/d/977dab/32.png) [@DarrenS](https://boards.straightdope.com/u/DarrenS)\ **Post date:** [January 12, 2003, 2:22am UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/5 "2003-01-12T02:22:04Z")
Another possibility is that your signal strength is weak, occasionally dropping below the acceptable threshold and causing your connection to die. This happened to me too - the Adelphia engineer eventually ascertained that some other engineer had installed a splitter on the common junction box for my housing complex, causing my signal to be only just acceptable. Have your cable company send a tech out to check the signal strength. ---
**Author:** ![Una\_Persson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/una_persson/32/346_2.png) [@Una\_Persson](https://boards.straightdope.com/u/Una_Persson)\ **Post date:** [January 12, 2003, 4:58am UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/6 "2003-01-12T04:58:58Z")
> [@](#): > > \*Originally posted by Bob55 \* > \*\*Overheating is a possibility, but the fact that it happens when the 2nd computer turns on and starts to use the network makes me think it’s something with IPs…but it does it randomly even when just 1 computer is on. As far as IPs go, I assume mine is dynamic but I thought once I had one it stayed with that IP until I reset the Cable Modem. Also, are IPs controlled by the router? Any way to fix this? \*\* Does your Belkin router do NAT? Or are both PCs trying to pull down separate IP addressees? On dynamic IP allocation, there is an expire date which is set by the DHCP server. Typically, you cannot have any control over this. This expiry can be as short as 1 second or as long as forever, but practically speaking it is typically 2-3 days or so. ---
**Author:** ![SavageNarce](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@SavageNarce](https://boards.straightdope.com/u/SavageNarce)\ **Post date:** [January 13, 2003, 1:06pm UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/7 "2003-01-13T13:06:57Z")
Is your power stable? My cable modem cuts out on me when there are power fluctuations on the line, and I have to go through the old unplug-and-reset cycle to get it working again. A small UPS would cure this, but it’s a question of how much bother I’m willing to go through to avoid spending money…😕 ---
**Author:** ![Balthisar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/balthisar/32/2825_2.png) [@Balthisar](https://boards.straightdope.com/u/Balthisar)\ **Post date:** [January 13, 2003, 2:07pm UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/8 "2003-01-13T14:07:07Z")
I’m on Comcast – for a while after the new neighbor had her cable connected, my connection would just die. The first time I reported it, they told me I needed to swap my old @Home modem for a new Motorola. I did so, and still had problems – the only recourse was to unplug the _cable_ and plug it back in; power cycling did nothing. It was strange. Sometimes when I’m doing heavy uploading the cable connection will stop working. When I do heavy downloading it’s no problem. I think it’s the fault of the LinkSys router – I just hit reset and it fixes itself okay. I suppose it’s _possible_ that Comcast is changing my IP for heavy upload traffic, maybe thinking I’m running a server. I’ll have to look at my IP addresses next time. ---
**Author:** ![Skelji](https://avatars.discourse-cdn.com/v4/letter/s/b38774/32.png) [@Skelji](https://boards.straightdope.com/u/Skelji)\ **Post date:** [January 13, 2003, 3:07pm UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/9 "2003-01-13T15:07:15Z")
I have a similar setup at home - 3 PCs with a Linksys router, Knology cable service. I know that my equipment works, my lines are good, and I have the proper signal strength. For absolutely no reason, the cable will go out on average of about once a day. I can see the activity light on the modem go out, then after a minute or so it flashes amber, then back to a steady green as service is restored. I’ve spoken to the cable company, and they say that it’s either some type of switching (huh?), or they are releasing my IP (even though it hasn’t changed for over a year). Yes, I have a dynamic IP. I know 4 other people in my neighborhood with the same service, and they say the same thing. Occasionally, the service will be out for an extended time. I used to reset my modem and router each time my connection dropped, but now I only do so if it’s out more than a few minutes. Most times, the service resumes on its own. When it drops, it doesn’t seem to matter whether 2 or 3 PCs are downloading, or only one is browsing. ---
**Author:** ![Tannim](https://avatars.discourse-cdn.com/v4/letter/t/0ea827/32.png) [@Tannim](https://boards.straightdope.com/u/Tannim)\ **Post date:** [January 13, 2003, 3:07pm UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/10 "2003-01-13T15:07:31Z")
I am using a belkin router and Roadrunner as well. I had that problem but I think mine was a little worse. I had to reset everything every couple of hours. I updated the firmware on the router and now it hasn’t happened since. ---
**Author:** ![Bongmaster](https://avatars.discourse-cdn.com/v4/letter/b/6a8cbe/32.png) [@Bongmaster](https://boards.straightdope.com/u/Bongmaster)\ **Post date:** [January 13, 2003, 3:39pm UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/11 "2003-01-13T15:39:39Z")
I have also had issues with signal strength causing that problem. Look for fuzzy pictures on your TV’s lower channels. The guy came out, swapped a cable joint in the closet and it cleared up both the connections being dropped and the fuzzy display. ---
**Author:** ![GOM](https://avatars.discourse-cdn.com/v4/letter/g/5f9b8f/32.png) [@GOM](https://boards.straightdope.com/u/GOM)\ **Post date:** [January 13, 2003, 5:31pm UTC](https://boards.straightdope.com/t/why-does-my-cable-modem-randomly-stop-working/148060/12 "2003-01-13T17:31:11Z")
Thanks for asking about this. I thought I was the only one having problems… On my machine, the only time I have the any problem with our cable modem is on this board. When I switch to Juno, everything works fine. That seems strange. No. I take that back. There is one other board that it happens on, but in that case it is only when I am trying to post. hmmm Now that I think about it, I only have the problem with this board when I am trying to post. That doesn’t make much sense to me, but then I’m a computer idiot.