I have a RUTX12 connected to a D-Link DGS-108 gigabit switch (which has been working flawlessly for over a year). At first I had DHCP disabled and was only using static IP addresses on the network, and that seemed to be stable for a few days. I have since enabled DHCP on the RUTX12, and today I started having issues where the RUTX12 would become unreachable. Upon checking the D-Link switch, I noted that neither the 10/100 Mbps or 1000 Mbps lights were on. If I unplug the RUTX12's ethernet cable from the D-Link switch, and plug it into a new port, it suddenly starts working again, and the 1000 Mbps light comes on.
There are several other devices (both 100 Mbps and 1000 Mbps) connected to the switch that keep their connection without a problem and have been plugged in for months at a time, so it doesn't seem to be the switch.
What could be causing this loss of ethernet connection after enabling DHCP (which works)? Maybe the DHCP enabling is just co-incidental, but either way, the RUTX12 (and only the RUTX12) is losing the ethernet connection to the switch.
Edit: It seems that even with DHCP disabled, this happens every few days. It's just much more frequent with DHCP enabled. So this is not specific to DHCP.