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eircom D1000 modem U
ser’s Guide
Chapter 9 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 90
How NAT Works
NAT Table
LAN
192.168.1.13
192.168.1.12
SA
192.168.1.10
Inside Local
IP Address
192.168.1.10
192.168.1.11
192.168.1.12
192.168.1.13
Inside Global
IP Address
IGA 1
IGA 2
IGA 3
IGA 4
SA
IGA1
WAN
192.168.1.11
192.168.1.10
Inside Local
Address (ILA)
Inside Global
Address (IGA)
9.6.4 NAT Application
The following figure illustrates a possible NAT application, where three inside LANs (logical LANs
using IP alias) behind the Device can communicate with three distinct WAN networks.
Figure 91
NAT Application With IP Alias
9.6.5 NAT Mapping Types
NAT supports five types of IP/port mapping. They are:
Summary of Contents for eircom D1000
Page 2: ...Copyright 2013 ZyXEL Communications Corporation...
Page 3: ......
Page 12: ...10 eircom D1000 modem User s Guide...
Page 13: ...PART I User s Guide 11...
Page 14: ...12...
Page 18: ...16 eircom D1000 modem User s Guide...
Page 26: ...Chapter 2 Introducing the Web Configurator 24 eircom D1000 modem User s Guide...
Page 27: ...PART II Technical Reference 25...
Page 28: ...26...
Page 78: ...76 eircom D1000 modem User s Guide Chapter 5 Wireless LAN...
Page 110: ...10 8 eircom D1000 modem User s Guide Chapter 6 Home Networking...
Page 126: ...Chapter 8 Quality of Service QoS 124 eircom D1000 modem User s Guide...
Page 136: ...134 eircom D1000 modem User s Guide Chapter 9 Network Address Translation NAT...
Page 148: ...146 eircom D1000 modem User s Guide Chapter 12 Filter...
Page 168: ...Chapter 14 Parental Control 166 eircom D1000 modem User s Guide...
Page 174: ...Chapter 15 Certificates 172 eircom D1000 modem User s Guide...
Page 180: ...178 eircom D1000 modem User s Guide Chapter 17 Traffic Status...
Page 182: ...180 eircom D1000 modem User s Guide Chapter 18 User Account...
Page 184: ...182 eircom D1000 modem User s Guide Chapter 19 System Setting...
Page 187: ...185 eircom D1000 modem User s Guide Chapter 20 Time Setting...
Page 188: ...Chapter 20 Time Setting 186 eircom D1000 modem User s Guide...
Page 196: ...Chapter 23 Backup Restore 194 eircom D1000 modem User s Guide...
Page 210: ...Chapter 25 Diagnostic 208 eircom D1000 modem User s Guide...
Page 216: ...214 eircom D1000 modem User s Guide Chapter 27 LED Descriptions...