Incoming calls and "Use static IP..." settings

[gdmitry]

Hi all!

 

There are 2 PCs. One has IP 10.72.50.235 (VoIP phone) and another is behind the router with NAT. The WAN port of router is 10.72.52.247, IP of second PC - 192.168.0.4. See below:

 

 

 

My Network settings in ET:

 

 

 

Ports 5060-5070 on router are forwarded to ports 5060-5070 on PC.

Case 1. When I call from PC to VoIP phone everything works fine. In Wireshark I can see that in Session Description (field Connection Information) IP 10.72.52.247. Here is the packet's dump:

 

 

 

Case 2. When I call from VoIP phone to PC it doesn't work because Express Talk sends "IP 192.168.0.4" in Session Description (field Connection Information) in packet "Status-Line: SIP/2.0 200 OK". But in field "Owner/Creator" it sends 10.72.52.247. In this case VoIP phone tries to send ACK to IP 192.168.0.4. Of course PC doesn't receive this packet (and RTP!). Here is the packet's dump:

 

 

 

 

Is it correct?

 

Thanks in advance!