I setup a NetBird-Net I have a ubuntu-server running a network office-lan with two resources office network subnet 192.168.22.0/24 and office dmz network 192.168.1.0/24.
I have a UMC6302 PBX running under 192.168.1.88, that I want to reach with Linphone from my android device, that has the latest beta client on it.
Is there a way to access the PBX?
You may have to apply to the ios/android/phone beta and then setup a network for that subnet. Or a resource
Once setup, you can connect to it either over an IP or a domain if you have a dns server on the peer that you can use.
I have NetBird running on the Server 192.168.22.2.
The PBX is running on the DMZ 192.168.1.XX.
Is it possible that the Server on 192.168.22.XX is
also a peer for the 192.168.1.xx subnet?
Depends on your networking setup and if it allows cross subnet communication. It could work, but only if your network allows you to do so. You’ll have to check with your networking department or your DHCP/Switch configuration.
Apart from that, it’ll depend on how you want to reach the machine. Either over the IP or domain.
Got it working.
Created a network office-dmz with just the UMC6302 as a resource (192.168.1.88/32)
and the ubuntu server (192.168.22.1) as a peer.
Thanks for the help.
Just working on WiFi not on mobile-network. 
I created this Network:
and this Policie:
When I’m in my WiFi, I can use Linphone with the UCM6302 PBX,
but when I’m disconnect the WiFi, I can’t use Linphone any more.
Mobile device is assinged to the umc-user group.
What am I doing wrong?
The policy has to be made to the resource, not the subnet/group i think. Try using the “Add Policy” button within the network. So umc-user → [resource]