My Linksys WRT54GS2 V1 has begun to display ghost wired connections in the last weeks. As you can see from the images I have nothing connected except for the power cable.
I have tried a hard reset and factory defaults, also leaving the router disconnected all night.
The DHCP list show no clients but the one I'm connecting from.
The problem this causes is limited connectivity for Wireless devices and no connection at all for wired connections. Only my wireless laptop can connect always, and a wired connection can connect sometimes.
After setting a mobile wifi configuration to static instead of DHCP, I managed to be able to connect that device. So I guess there's a problem with the DHCP of the router.