ZyXEL Communications ISG50-ISDN Application Note page 34

Goal to achieve:
Connect the ISG50 to the DMZ of the ZyWALL. The USG provides security services and the ISG50 acts as a pure IP PBX to provide VoIP services.
IP phones from the Internet can register to ISG50 through USG's WAN IP.
Condition:
USG:
- WAN IP: 59.124.163.156
- SIP server IP (ISG50): 172.16.1.10
USG:
Step 1. Click CONFIGURATION > Network > Interface > Ethernet to assign a WAN IP to USG.
ISG50:
- WAN IP: 172.16.1.10
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