A Belkin router playing up


Do you powercycle both modem and router after mac cloning in dynamic mode? Have you tried a hard reset on the Belkin unit? Have you tried updating the Belkin routers firmware*? Can you not get hold of another router to test as suggested by heero_yuy ?
*Be sure to match up models including version 1 or 2.
If the Belkin router is faulty and you have brought the Belkin unit within the last 2 years then return to Belkin for a replacement.