Hello.
I'm doing a lot of VC installing and almost on every site I've encounter same problems with network. As known, H.323 is no NAT-friendly. So, to quick-tests on customer site and production too, was impemented Gatekeeper with H.460 (17,18,24) support on "white" IP address.
So, there is no longer need to do port-traversal or DMZ on most sites. Also, this is a solution for several H.323-systems in same network to dial out without H.323-SBC, like VBP.
IP address is 92.249.69.203
Please, feel free to use it 
If someone wants to know, hot it was implemented - http://samael28.blogspot.com/2012/10/gnugk-vbp-e-vbp-st.html (Russian)