Thanks.

MY bets are that it's either Comcast, who can be pretty erratic where we live at times, or the router (or one of the other two boxes). VOIP doesn't show any signs of being impacted (it is very noticeable when it is) so I am guessing it is downstream of the telephone adapter- which is the wireless router and connections.

I am still puzzled by the multiple "null" connections (usually three). I did another experiment last night where I checked who was connected (3 out of the 7 DHCP clients were "null") and then restarted the router to dump everyone off, leaving one PC and the "null" corresponding to the N810.

It is possible but not likely that the N810 is connected with one IP address and then re-requesting DHCP due to some issue; hence the multiple occurrences of null device. But not likely.

Really not likely that it's one of my neighbors.

I guess my next step will be to swap out the wireless router and see if that addresses it.

One thing that would help: Is there some way to force the N810 to identify itself to the DHCP as something besides Null?