Panasonic Hybrid IP-PBX Manual page 14

2.1 VoIP Requirements
Does the router not use network address translation (NAT/NAPT)?
If the router uses address translation techniques (e.g., NAT/NAPT) to convert between global and local IP
addresses, VoIP communications between the IP-EXT16 card and IP-PT cannot be carried out effectively.
Therefore, the routers used to access the IP network must not use NAT/NAPT. Generally, NAT and NAPT
are features that are available with routers.
Using NAT/NAPT
Local IP Address
Domain
Global IP Address
Domain
Local IP Address
Domain
14 Information about IP Proprietary Telephones
Router
IP Network
Router
NOT Using NAT/NAPT
Local IP Address
Domain
Router
IP Network
Router