zerotier for connection between 2 LMs

[bmodeco]

Hi,

I will end up having 2 KNX-sites (home/office) running both an LM.

I would like to trigger some groupadresses from one site to another. Both sites have an independent VPN-server (openvpn).

I was thinking to (don't know if this is possible through a script):
- start openvpn and connect
- send remote command
- close vpn (no need to keep the vpn open all day)

From what i understand it should also be possible with the zerotier when i connect both LMs to the same network.
One question with this: do they retain their IP-adres after reboot (is it fixed)?

For obvious reasons i do not want to open any KNX-ports on the router...

Any ideas about this?

Thanks, 
Bart