We currently use SSL VPN SA-4000 Ver. 5.5R2.1 and we have been having issues since day one with RDP sessions on XP machines. We used to use an SSH tunnel through a Unix box to get outside access to our networks however due to security problems we opted to go with SSL VPN. The problem is that users RDP sessions run at least 2 - 3 times slower through the VPN than the SSH tunnel. Does anyone know why and or how to speed up the sessions through the VPN? Is it even possible to speed it up. Users are currently using the lowest video settings as possible when using the RDP sessions.
Make sure client-side logging is turned off. It slows down things and there was a bug in some versions of the firmware that caused the client -side logs to grow and grow and grow. It caused dramatic slowdowns in RDP sessions.
Logging/Monitoring -> Client Logs -> Settings - Un-check them all unless you're actively troubleshooting a problem.