ZyXEL Communications ZyWALL 1000 User Manual
Chapter 6 Tutorials
ZyWALL USG 1000 User’s Guide
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Figure 96 Create a Firewall Rule
6.7 NAT Loopback
The NAT 1:1 example in
maps a public IP address to the private IP
address of a LAN SMTP mail server to allow users to access the SMTP mail server from the
WAN. LAN users can also use an IP address to access the mail server. However, you need to
configure NAT loopback for LAN users to use a domain name to access the server.
WAN. LAN users can also use an IP address to access the mail server. However, you need to
configure NAT loopback for LAN users to use a domain name to access the server.
Figure 97 LAN Computer Queries the DNS Server
A LAN 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.
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.
192.168.1.21
xxx.LAN-SMTP.com = ?
LAN
DNS
192.168.1.89
xxx.LAN-SMTP.com = 1.1.1.1
1.1.1.1