Why does my cable internet keep going off?

Food?

First off: yes, it's Comcast.

Daily now, the internet at my house goes out. To fix it, we just reset the router and the cable modem, and it works again. This is inconvenient. It doesn't seem like it's an issue with Comcast itself (somehow), so what could it be?

unilateral

This happened with us once. The internet would go about 3 or 4 times a day for a few minutes each. We called and they said to ground out the cable wire on something metal and plug it back in. I told them it was still unacceptable. After two weeks of fighting with them, they finally sent somebody and gave us a new modem. It hasn't happened since that, and thats been roughly a year ago. I don't know if its the same problem with yours, but it sounds similar.

Geod

I had something very similar as well, but we never figured it out. I'd say the modem, though we always blamed Comcast.

Tomanta

It's likely the modem. Bypass the router, if the problem continues than I'd strongly suspect the modem. Unless it happens at roughly the same time every day, in which case it /could/ be environmental (i.e., everyone getting home at 5 and logging on) - but even then I'd probably say modem.

Sarcastro

You may want to figure out which device is giving you grief. When it happens again, just do the router - if it comes back on, then its a router thing. If it doesn't, and you have to reboot the modem and the router, then its a modem thing.

If it comes back right away after rebooting the modem, definately a modem/signal problem. If it stays out or takes a few minutes to come back, you might be having micro-outages from the ISP.

Two basic causes; a constant stream of signal errors, which a modem can only handle so many of before it needs a reboot (this is what additional grounding can fix), or a DHCP client problem inside the modem which prevents it from grabbing (or keeping) an IP address when the external IP changes. Every time the IP lease expires, poof no more internet until you reboot the client.

There is a third cause as well, in that your signal may just be crap all the time, and the rate adaptive nature of the device can't handle it all the time. A DSL connection works with a series of channels, about a thousand or so, all providing a slice of bandwidth. A modem will choose the best channels and eliminate the noisy or unusable ones. Over time, when a channel becomes bad, it is eliminated from the list of usuable channels, and the modem will only use the ones it's found and labeled as good. Next gen modems regen this list every fifteen minutes or so, but sometimes that process breaks, and the regen on the channel list doesn't occur.

Everytime you lose a channel, it stays off the list: lose too many and the connection drops below critical mass (about six channels or so) and the whole thing drops out instantly in an ugly mess. Rebooting the modem at this point forces the modem to resort out all of the availible channels again from scratch, rebuliding the connection until the same thing happens again. Its a problem within the modem, and generally this problem is hallmarked by your connection getting slower and slower until it dies, and then coming back again full speed after a modem/router reboot.

so nutshell: Good odds on a modem issue made worse by a less than ideal signal.

Treeloot

We had this problem once, and it turned out it was because our coaxial cables weren't attached very well at a certain spot in the house. We screwed them tighter and haven't had a problem since.

JohnnyCache

I used to have this problem and it seemed to drastically reduce/go away when I stopped using bitlord

MikeRyu

I'm not sure if this is the same but ours needs about half an hour or so when first switched on before it'll connect and it will now disconnect shortly after that and reconnect again. Same pattern every day.

Rhino

This happens to me when my modem gets to hot

MikeRyu

Actually I'd like to add to this, does the quality of cable affect the connection? I have the computer upstairs and have had a telephone line put in up here. It has a box but I think it might just be a glorified extension lead. Could the fact that I am not plugging in to the original telephone socket or the quality of the cables I am using have an effect on the connection? It's actually got worse just today. It seems to just go in random cycles of good upstream/downstream then a long period of bad downstream good upstream for a long time and, just like today, bad everything. Now it's disconnecting a lot. It just seems so random and temperamental to me.