Such a rare thing I've never seen until I started toying with my modme and rebooting it when it is set to DMZ. Well I've noticed that when the DMZ ip address for the device set is between 60.xxx.xxx.xxx~71.xxx.xxx.xxx the signal decreases(based on the modem's line statistics) When the DMZ ip address for the device set is between 72.xxx.xxx.xxx~75.xxx.xxx.xxx(I haven't seen any ip address changed to 73.xxx.xxx.xxx or higher) the signal increases dramamtically. I had to make several tests and prove if it actually was true. One thing is that only the upload speed only increases or decreases. Maybe the different ip addresses have to do with the routers of the internetwork from which the DSL Gateway retreives the DMZ address (the distance of the router).