I currently have a Cisco 3620 connected to the internet via the Transedge(Newedge) network. Behind that I have clients with different types of routers. Clients with Hawking or Linksys routers run into problems logging into hotmail or running windows updates. Both just hang and never finish loading. If the client connects directly without using the router then the sites work just fine. If I set the MTU to 1500 on the Linksys router it starts working fine. The Hawking/Linksys routers worked just fine behind a Cisco 2620 connected through Sprint before. Any ideas what would be causing the problem?

That is an odd problem. If it wasn't for the fact that the clients directly connecting working ok, I would say it might have been an issues with the client's clock being way off. Believe it or not, I seen where Windows update doesn't work if the Windows clock is way off the correct time or date. I once ran into a problem at a remote location with a client connecting to a Terminal Server. It was going through two routers, and the problem ended up being the Terminal Server license packet was getting fragmented and therefore not permitting the client connection. Since you mentioned that fixing the MTU on one of the routers help solve the problem , I'd look for packet fragmentation.

Yeah, that's what I'm thinking. I upgraded the firmware on the linksys router and it works. One of the fixes in the firmware is: 5. Fixed fragment packet table error. So I can fix the problem on some linksys routers...but others there still isn't a solution. I'm wondering if my Cisco router handles the fragments different or something? I'm so lost right now :(

I had the same prob on my network. PC's behind Linksys router could not access Windows Update or hotmail, though MSN messenger worked. All PC's hung at "Passport" login, and eventual "Page cannot be displayed." Upgraded firmware, which did not solve. Only solution was to specify MTU size of 1492. Everything started functioning perfectly. No other changes have taken place on my network-- our PC's just suddenly stopped accessing sites around the date you posted your first message. Linksys thinks it was a change in the way our ISP handles packets, but I think it was a change MS made around the time of their "detail-less" hotmail outage. Server changes, to be sure.