I have a Linksys RT41P2-AT router using AT&T Callvantage Voip. For 6-8 months i thought my isp was having problems because every site i loaded was very laggy stopping multiple times during loading even a simple, small page. Loading certain sites like ubid would go crawlingly slow, when they would fly on friends connections with the same isp. Any full size image on webshots.com would load at exactly 1.5KB/sec. Overall page loading was bareable (barely), but I knew something was wrong.
For kicks one night I reset the router to factory defaults, and the problem went away. All sites loaded almost like they were local, and webshots would load full size images at up to 900KB/sec (my isp's max speed). I had no idea what i was missing from my ISP
I started playing with router settings, and enabled block ping requests, and filter ActiveX in the control panel. After saving settings, everything went to hell again. Resetting to factory defaults immediately solved the problem. I have tried only enabling block ping request, or only enabling filter activex, with the same result. The wierd part is that even after disabling them the problem doesen't go away. The only solution is to reset to factory defaults.
Is there any reason my router is doing this? It is not an isolated issue, because this is my second RT41P2-AT that has done this. My original model was returned to AT&T because the voip circuitry failed after less than a year.