I have a strange issue with my setup: arduino uno + ethernet shield (+a couple of sensors like pir, temp and 2 relays). It has been working ok for a year or two, but during the past 2 weeks ethernet connection randomly stops (after a couple of hours and sometimes after a couple of days). The arduino continues to work (i have led that flashes when the loop starts and when it ends) but the ethernet shield stops ( i cannot ping it and it does not receive commands). In order to fix the problem i have to re-plug the ethernet cable). Has anyone experienced smt similar before? Any suggestions on how to fix it?