Set Up A Firewall Rule For H.323 - ZyXEL Communications ZYWALL USG 20 Manual

Click Configuration > Network > NAT > Add.
2
Configure a name for the rule (WAN-LAN_H323 here).
You want the LAN H.323 device to receive peer-to-peer calls from the WAN and
also be able to initiate calls to the WAN so you set the Classification to NAT 1:1.
Set the Incoming Interface to wan1.
Set the Original IP to the WAN address object (WAN_IP-for-H323).
Set the Mapped IP to the H.323 device's LAN1 IP address object (LAN_H323).
Set the Port Mapping Type to Port, the Protocol Type to TCP and the original
and mapped ports to 1720.
Click OK.
Figure 89 Configuration > Network > NAT > Add

7.9.3 Set Up a Firewall Rule For H.323

The default firewall rule for WAN-to-LAN traffic drops all traffic. Here is how to
configure a firewall rule to allow H.323 (TCP port 1720) traffic received on the
WAN_IP-for-H323 IP address to go to LAN1 IP address 192.168.1.56.
ZyWALL USG 20/20W User's Guide
Chapter 7 Tutorials
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