Zyxel ZyWALL USG 50 [118/150] Set up a nat policy for the ippbx

Chapter 5 Managing Traffic

ZyWALL USG 20-2000 User’s Guide

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5.7.2.2 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.

•Set the Incoming Interface to use the WAN interface.

•Set the Original IP to the WAN address object (IPPBX-Public). If a domain name is registered

for IP address 1.1.1.2, users can use it to connect to for making SIP calls.

•Set the Mapped IP to the IPPBX’s DMZ IP address object (IPPBX-DMZ).

•Set the Port Mapping Type to Port, the Protocol Type to UDP and the original and mapped

ports to 5060.

• Keep Enable NAT Loopback selected to allow the LAN users to use the IPPBX.

• Click OK.

Figure 50 Configuration > Network > NAT > Add

5.7.2.3 Set Up a WAN to DMZ Firewall Rule for SIP

The firewall blocks traffic from the WAN zone to the DMZ zone by default so you need to create a

firewall rule to allow the public to send SIP traffic to the IPPBX. If a domain name is registered for

IP address 1.1.1.2, users can use it to connect to for making SIP calls.

Click Configuration > Firewall > Add. Set the From field as WAN and the To field as DMZ. Set

the Destination to the IPPBX’s DMZ IP address object (DMZ_SIP). IPPBX_DMZ is the

destination because the ZyWALL applies NAT to traffic before applying the firewall rule. Set the

Access field to allow and click OK.