For some time I've been struggling with the following problem. This is my setup: Draytek Vigor 2820 with proper NAT setup, different port to internal port 3389 to a Terminal Server 2003. All is working great, remote users (max 8) can connect to it. DNS setup external so no IP address needed. All of a sudden no external connection is possible anymore. RDP sessions freezes, no connection can be made. If I connect locally, no problem, if I connect externally through a Lan to Lan connection (Draytek to Draytek) also no problem. But the moment I try to use the external connection through NAT, no connection possible. Sometimes it's just enough to reboot the Draytek router but other times I also have to reboot the server to establish a connection again. And even sometimes I just let it be and after a few hours, max a day, everything is working fine again.
Does anybody have any ideas?