For several years now I have had an intermittent problem with my modem (ADSL2 Phoneline Ethernet).

The modem will suddenly reboot itself.

This has happened with two different brands of modem so I feel sure it is not the modem at fault.
The reboot may happen only once in a day or it might happen so often that nearly all day is
spent rebooting with one to five minutes between reboots.
The time when I do not have the problem can vary from one day up to three months. The rebooting
seems to occur randomly at any time of year or weather pattern. Normally it happens so seldom
I can put up with it but recently it annoyed me enough to post this.
It's happened with every OS I have had on this and my previous computer. That being Slackware and lots of Linux distributions I've installed for fun. Also Windows where you can watch the lights on the modem change as it reboots even though I have the internet disconnected.

My initial thought is a weak power supply - or even a bit of corrosion on the connections to the power supply. But that can depend on what kind of power supply - an external brick is the one I've had to deal with before.

It may also depend on the weather and the phone line (bad static on the line can cause the modem to hangup and reconnect), but with completely random disconnects would lead to think of hardware failures.

your ISP is likely the cause

the connection dropping

think of it as a power grid brown-out or momentary power outage

the same things happens with dsl and cable

could also be bad hardware

contact your isp and have them switch it out

Hi,

Since this is a DSL modem I would make sure that your line is clear. Have the ISP do a line check and be sure to check all the filters connected to all phones within the line area. Bad filters can cause this type of issue.

Another thing would be sure to have a good AC source, check the socket or check what is used on that same circuit that could create power line signal injection (motors, refrigerators or any large on/off system). If you do not have experience working with electrical then have a qualified person do the checks.

You could use a UPS for the modem to insure the problem is not due to drop/brown/noise on the AC line that can cause outage or a intermittent power issue(noise, power drop/changes). You can get the small UPS designed for modems for around $30 US.
Intermittent problems can be very hard to track or diagnose.
Hope this helps.

Some good ideas here giving me plenty to think about. New filter and cables seems like a useful first thing to try.
The modem has been alright lately so I might as well close this thread.