SoftEther VPN User Forum

I have a strange problem (windows) when connecting to a rdp server (windows 10 rdp, not terminalserver):
If I am located in a foreign Wifi, then connect to the remote network using the SE client. Connection is ok, but I cannot access any host using rdp in the remote network.
If I use the mobile brodband adapter (built into the notebook) to connect to the VPN everythiing works.
The VPN is a L2 bridge VPN
I can fix this by lowering the MTU of the SE VPN adapter to 1290 (tested a ping with the DF flag and found that from 1300up the ping will not return).

What could be the reason behind this?

The RDP MTU issue can be fixed by disabling URCP but you also have MTU ping problems. Perhaps a global URCP-off can fix it too.

Thank you!
I never heard about this issue, but now found several posts in the internet about it.
What I do not understand: global URCP turn-off: Does this effect other services besides RDP, and, how can I turn this off global?

URCP is enabled by default for all applications. Disabling it for RDP-only is documented. I suppose there may be a way to turn it off 'globally' but it is my speculation.

Can anyone please discribe where exactly to modify the MTU setting?

Destination server, connecting client, SE SecureNAT settings, SE bridge interface? All?
Which seams suiteable or reasonable?

Please let us know.

on RDP server PC:

in my case I had to change the MTU on the client (see first post).