User manual

VOPTech GoIP User Manual

The trunk agent protocol supports encryption on communications over the gateway. This

feature needs the support of the server developed by VOPTEL Technology.

3.5.6.3 Media NAT Traversal

The media NAT (firewall) traversal is classified into four types:

A. No firewall

The firewall traversal mechanism is not supported.

B. Port Transparency/DMZ

The port transparency is used to transfer the network port on the LAN interface to the

computer or the server in the LAN. This feature enables external users (through the Internet in

most cases) to share the services of internal servers (such as FTP, HTTP, and Telnet).

The port transparency supports the address of the gateway and response server. The gateway

is a communication device that connects two different networks. The response server is a

standard service device that implements the ECHO protocol.

C. STUN (RFC 3489)

The Simple Traversal of UDP over NAT (STUN) is a protocol that enables the SIP telephone

to detect the existence and type of the firewall installed in the computer. This parameter

indicates the SIP address of the STUN server.

Note: The STUN protocol supports the SIP gateway only.

D. Trunk Agent

The trunk agent protocol is a firewall traversal technology developed by VOPTEL Technology.

It enables the products of VOPTEL Technology to be applicable for most LANs. It involves

the address, port, user name and password. The trunk agent protocol supports encryption on

communications over the gateway. This feature needs the support of the server developed by

VOPTEL Technology.