How To Use An Ippbx On The Dmz - ZyXEL Communications ZyWALL USG Series Application Notes

4.7.2 How to Use an IPPBX on the DMZ

This is an example of making an IPPBX x6004 using SIP in the DMZ zone accessible from the Internet
(the WAN zone). In this example you have public IP address 1.1.1.2 that you will use on the WAN
interface and map to the IPPBX's private IP address of 192.168.3.9. The local SIP clients are on the
LAN.
Figure 48
4.7.2.1 Turn On the ALG
Click Configuration > Network > ALG. Select Enable SIP ALG and Enable SIP
Transformations and click Apply.
Figure 49
4.7.2.2 Set Up a NAT Policy for the IPPBX
Click Configuration > Network > NAT > Add > Create New Object > Address and create an
IPv4 host address object for the IPPBX's private DMZ IP address of 192.168.3.9. Repeat to create a
host address object named IPPBX-Public for the public WAN IP address 1.1.1.2.
• Configure a name for the rule (WAN-DMZ_IPPBX here).
• You want the IPPBX to receive calls from the WAN and also be able to send calls to the WAN so you
set the Classification to NAT 1:1.
IPPBX Example Network T opology
Configuration > Network > ALG
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