[OpenSIPS-Users] Cannot Register X-Lite Soft-Phones From One Network To An OpenSER In Another Network

[Kemp, Larry]

OpenSER Community;

I was wondering if anyone could help point me in the right direction with OpenSER. 

I've successfully installed OpenSIPS 1.2.2 on Debian 5.0.3 Linux (Kernel 2.6.26-2-686) using Flavio's helpful book "Building Telephony Systems with OpenSER" from Packt Publishing. I am trying to get two X-Lite v2.0 Soft-Phone clients to register to the OpenSER. When I run the command "openserctl ul show" however I do not see any phones registered. When I perform "ngrep -p -q -W byline port 5060 >test.txt" and look at the SIP messages on the OpenSER I see the following that seems to incrementing: 

.P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint: outbound..P-hint

I have NAPTR, SRV and A records in my DNS servers and the server resolves correctly. I am thinking it is some kind of SIP-routing-loop because I am going from one private net, out into the internet, then back into a private DMZ. All ports are open for OpenSER and the Clients. Like this:

 ________________                       __  __                     ___________________
|     LAN        |                    _/  \/  \_                  |       DMZ         |
|  ------------  |      ------       /          \       --------  |       -------     |
| [Soft Clients]------>[Router]---->[  Internet  ]---->[Firewall]------->[OpenSER]    |  
|  ------------  |      ------       \_ & DNS  _/       --------  |       -------     |
| 172.20.30.x    |     Router's        \__/\__/         OpenSER's |   10.100.100.199  |
|________________|     Public IP                        Public IP |___________________|
                      208.76.x.x                       208.76.x.x 

Would I be right in asuming that the soft=phones and OpenSER must be on the same subnetwork? 
Like this:
10.100.100.199 = OpenSER
10.100.100.198 - XLite Client (Extension 1000)
10.100.100.197 - XLite Client (Extension 1001)
I am going to install some soft clients on that DMZ /24 (10.100.100.0 /24) to see if I am right. So if I am and they can then talk is it a routing issue then?

I am on page 71 and 72 in Flavio's book. If one of you that has experience with this particular or a similar config, if you could please point me in the right direction that would be outstanding. I can attach logs if need be.

Thanks,

Larry Kemp
Network Engineer
U.S. Metropolitan Telecom, LLC
Bonita Springs, FL 34135