ZyXEL Communications ZyWALL USG100-Plus User Manual page 111

• 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 46 Configuration > Network > NAT > Add
5.6.2.3 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.
ZyWALL USG100-PLUS User's Guide
Chapter 5 Managing Traffic
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