ZyWALL User's Guide

Chapter 18 ALG
ZyWALL USG 100/200 Series User’s Guide
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For example, you configure firewall and virtual server rules to allow LAN IP address A to
receive calls through public WAN IP address 1. You configure different firewall and port
forwarding rules to allow LAN IP 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 1 and calls from LAN IP address B go out through WAN IP address
2.
Figure 235 VoIP with Multiple WAN IP Addresses
Finding Out More
• See Section 5.4.21 on page 120 for related information on these screens.
• See Section 6.8 on page 159 for a tutorial showing how to use the ALG for peer-to-peer
H.323 traffic.
• See Section 18.3 on page 330 for ALG background/technical information.
18.1.3 Before You Begin
Configure and enable NAT in the ZyWALL before you use the ALG.
18.2 The ALG Screen
Click Network > ALG to open the ALG screen. Use this screen to turn ALGs off or on,
configure the port numbers to which they apply, and configure SIP ALG time outs.
" If the ZyWALL provides an ALG for a service, you must enable the ALG in
order to perform bandwidth management on that service’s traffic.