Hello everybody,
A customer runs Windows Server 2019 terminal server farms. From the local network, everything is fine. Users get perfectly connected and load-balanced to the RD servers. However, if the log on to the domain through a VPN (TMG 2010) which does not block any
traffic, they can only only sometimes connect to the farm. When they fail, their Windows 10 RDP client just yields an "internal error" without being more specific.
We checked already:
* TMG does not block anything coming from the VPN to the inner servers or vice-versa. We also tried temporary firewall rules allowing any traffic in both directions.
* DNS resolution and contact to the domain controllers is fine from the LAN and through the VPN. There are DNS A records for each RD server, and for each RD server there is a DNS A record with the farm name, pointing to each of the RD servers, for DNS round-robin.
* The RD broker (a separate server) load-balances the users just fine.
* The clients get a DHCP address for their VPN connection from VPN, also just fine.
* The clients CAN connect every time to the old 2008 R2 server farm which did not load balance. When they try to connect to a 2019 farm (with each farm consisting of 4 RD servers and its own broker and licensing server), the only connect sometimes, the other
time failing with the "internal error".
* The clients connect (locally and through VPN) using the same .rdp file pointing to the farm name. The do not use RDWeb currently, nor a RD gateway.
We have the suspicion (although not proved 100% yet) that the users can connect when a RD redirection is not needed/requested by the RD server that they initially contact via DNS round-robin.
Is such a symptom known? Does anyone have a clue what is happening here?
Best Regards, Stefan Falk