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.