Having a strange problem where only some clients connecting to a 2003 VPN server are experiencing slow connections between their machine and the server.
Here is the setup.
2003 Server SP2 2.3Ghz AMD Phenmom 2.30Ghz configured with VPN under Routing and Remote Access.
ISP Verizon Fios 15 Mbs up/down. (very fast connection otherwise)
About 15 clients, most in the same state all running windows XP.
About 6 out of the 15 clients connect and have slow speeds. I have a constant ping going to all clients, and most are in the 20-50ms range. However, there are about 6 that randomly will be in the 800 - 1200 range, but not all the time. I thought it was hardware related, and put together an entirely new box, new Nics, MB, CPU, everything, same setup, same results.
The strange thing is these clients that are having the problem, can connect to another VPN server (Windows 2003 server) that I have setup on a different ISP and they work file, pings in the 20-50ms range.
I suspect it's something to do with my ISP and/or server configuration. I've tried dropping the MTU in the router. I had been just fwding the proper ports, but tried it in the DMZ as well. The router is a MI424-WR running 188.8.131.52.184.108.40.206.6 version of firmware. This is on a Verizon FIOS business account with static IP, and from what I know there should be nothing preventing me from running a VPN server. Speed tests and other network performance don't seem to be an issue; speedtest.net reports I'm getting close to 15/15.