ryecoaaron
At my view, Teamviewer daemon have to initiate connection to Teamviewers servers (something like server19408.teamviewer.com) for handshake, ID assignment, tunnel establishment, etc., before teamviewer client will get possibility to connect to target system.
Otherwise it will be impossible to connect remote system via internet thru NAT, routers, etc...
On this netstat output:
root@RDNS:~# netstat -ntap | grep teamviewer
tcp 0 0 127.0.0.1:5939 0.0.0.0:* LISTEN 16170/teamviewerd
we have only localhost listening for loopback purposes only.
There is no any other connection necessary for tunnelling between remote an local systems via Teamviewers servers.
That is the problem I guess.
Other thing, I cannot connect my remote system directly in the same local network, but teamviewer software allowed direct connection in the same local network, for Windows version at list.
I didn't check that you are the author of openmediavault-teamviewerhost plugin, I'm sorry for any possible inconvenience for you in case my issue opening on Github.
And you are right - that's the question for teamviewer support mostly.