Epson 3300 manual NAT Traversal, Manually Input NAT IP, Address, Auto Discovery NAT IP

3.7.8 NAT Traversal

NAT traversal is a challenge that all Service Providers looking to deliver public IP-based voice and multimedia services must solve. The goal of this function is to provide secure connection to subscribers behind NAT (Network Address Translation) devices and Firewalls. Overcoming this traversal problem will lead to widespread deployment of profitable voice and multimedia over IP services to any subscriber with broadband connection.

Disable	Disables this function. The feature is used if Vigor3300 has a
	public WAN IP address and not behind a NAT router.
Manually Input NAT IP	NAT IP Address - Type the IP address to be used as the NAT
Address	IP address. The feature is used when Vigor 3300V is behind a
	NAT router, and the NAT router uses a static WAN IP
	address. This value is the same as the WAN IP of the front
	NAT router.
Auto Discovery NAT IP	It is used when Vigor3300 is behind a NAT router, and the
Address	NAT router uses a dynamic WAN IP address such as a DHCP
	or PPPoE client. The Vigor3300 requires a STUN server for
	this option.
	The “STUN” (Simple Traversal of UDP through NATs)
	server is an implementation of the STUN protocol that
	enables STUN functionality in SIP-based systems. It is an
	application-layer protocol that can determine the public IP
	and nature of a NAT device sitting between the STUN client
	and STUN server.
	Semi-auto, need to config NAT – If you click this function;
	the user needs to configure NAT information.
120	Vigor3300 Series User’s Guide