Figure 222 Create A Firewall Rule; Figure 223 Lan1 Computer Queries The Dns Server - ZyXEL Communications ZyWALL USG 100 Series User Manual

Figure 222 Create a Firewall Rule

NAT Loopback Example
The NAT 1:1 Example on page 315
LAN1 SMTP mail server to allow users to access the SMTP mail server from the WAN. LAN1
users can also use an IP address to access the mail server. However, you need to configure
NAT loopback for LAN1 users to use a domain name to access the server.

Figure 223 LAN1 Computer Queries the DNS Server

A LAN1 user computer at IP address 192.168.1.89 queries the domain name (xxx.LAN-
SMTP.com in this example) from a public DNS server and gets the SMTP server's 1-1 NAT
mapped public IP address of 1.1.1.1.
ZyWALL USG 100/200 Series User's Guide
maps a public IP address to the private IP address of a
xxx.LAN-SMTP.com = ?
1.1.1.1
LAN
192.168.1.21
Chapter 16 Virtual Servers
DNS
xxx.LAN-SMTP.com = 1.1.1.1
192.168.1.89
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