ZyXEL Communications AMG1312-T10D User Manual page 124

Chapter 10 Network Address Translation (NAT)
Device keeps track of the original addresses and port numbers so incoming reply packets can have
their original values restored. The following figure illustrates this.
Figure 88 How NAT Works
LAN
192.168.1.12
192.168.1.11
124
192.168.1.13
SA
192.168.1.10
Inside Local
Address (ILA)
192.168.1.10
NAT Table
Inside Local Inside Global
IP Address
IP Address
192.168.1.10
IGA 1
192.168.1.11
IGA 2
192.168.1.12
IGA 3
192.168.1.13
IGA 4
SA
IGA1
Inside Global
Address (IGA)
WAN
AMG1312-T10D User's Guide