ZyXEL Communications ISG50 User Manual

 Chapter 20 ALG

ISG50 User’s Guide

address B to receive calls through public WAN IP address 2. You configure corresponding policy 
routes to have calls from LAN IP address A go out through WAN IP address 

 and calls from LAN IP 

address B go out through WAN IP address 2. 

VoIP with Multiple WAN IP Addresses

• See 

 for related information on these screens.

• See 

 for a tutorial showing how to use the ALG for peer-to-peer H.323 

traffic. 

• See 

 for ALG background/technical information.

You must also configure the firewall and enable NAT in the ISG50 to allow sessions initiated from 
the WAN.