Print

[Confusticated]

Check your log to see if the time it drops off the network coincides with the time the DHCP lease expires.
OR
Configure the plug with a fixed IP and see if the problem goes away.

[Tobi_2006]

My router's settings for the plug are already the following:

"Always use the same IP address:   Yes
DHCP Lease Time:   Infinite".

I also never had this problem with any other (Linux-) PC I have on the network and from time to time I had them running for a few days in a row.

[Confusticated]

The objective is to prove the fault is with the plug, not to cure it.

[Tobi_2006]

I thought that's what I did - the same problem does not occur with my other computers on the same network with the same router settings and more or less identical programmes. The internal IP address for the plug stays the same and the DHCP settings are set to infinite lease time.

I had a closer look at the plugs network behaviour, and it looks like there is no apparent pattern. The network is sometimes up for 6 or more hours, sometimes only for around an hour. I don't think it's related to the time of the day either, it appears to be random.