thank you for your reply. I shut down all the Firewalls behind the tailscale-relay-server and I still can’t reach a Windows machine over RDP.
The whole subnet is 192.168.1.0/24. And this is exactly what I setup as a “subnet-route” over tailscale.
Lets say the machine with tailscale installed is 192.168.1.100 with CentOS and the Windows machine is 192.168.1.200. They can see each other and ping, but there is no use of RDP (through the tailscale tunnel) possible.
There are just the default ACLs set.
Do you need to pay for that feature and therefore it is disabled?
Yes, RDP works the moment I turn off tailscales subnet routes. While they (the subnet-routes) are active the RDP within the subnet aren’t working (so I would expect at least they work over tailscale, but they don`t).
With source / destination IP you mean the tailscale IPs? Can I send them via PM?
I reinstalled the machine I used as relay. And jumped from CentOS 8 to CentOS 7.
There were no changes in the environment otherwise. And now it is working.
I can’t see where the issue was. Thank you for your time. Next time I just reinstall the machine…