D-Link DPH-125MS Product Manual - Page 32

Section 3 - Configuration NAT Traversal Settings NAT traversal is a challenge that all Service Providers looking to deliver public IP-based voice service must solve. The challenge is to provide secure connection to subscribers behind NAT (Network Address Translation) devices and Firewalls. This IP Phone implements NAT traversal function for solving the Firewall and NAT traversal problems. STUN: Simple Traversal of User Datagram Protocol through Network Address Translators is a protocol that allows applications to determine the types of NATs and firewalls that are in between them and the internet. STUN also provides the ability for applications to determine the public IP addresses allocated to them by the NAT. STUN Domain Enter the STUN domain name or IP address if Name/IP Address: STUN is enabled. User Defined E n a b l e o r d i s a b l e t h e s e t t i n g s f o r External IP/Port: configur ing the user defined exter nal IP address and port number. External IP Select whether you want to use the STUN Address: server to get the external IP address or use UPnP to get the external IP address. External SIP Port: Displays the External SIP port number. External Media Displays the External media port number. Port: UPnP: Enable or disable universal plug and play devices. Some NAT supports UPnP so STUN is not required and must be disabled. D-Link DPH-125MS User Manual 32