Chapter 11 Network Address Translation (NAT)
XMG3512-B10A User’s Guide
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11.9.3 How NAT Works
Each packet has two addresses – a source address and a destination address. For outgoing packets,
the ILA (Inside Local Address) is the source address on the LAN, and the IGA (Inside Global Address) is
the source address on the WAN. For incoming packets, the ILA is the destination address on the LAN,
and the IGA is the destination address on the WAN. NAT maps private (local) IP addresses to globally
unique ones required for communication with hosts on other networks. It replaces the original IP source
address (and TCP or UDP source port numbers for Many-to-One and Many-to-Many Overload NAT
mapping) in each packet and then forwards it to the Internet. The XMG 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 89
How NAT Works
11.9.4 NAT Application
The following figure illustrates a possible NAT application, where three inside LANs (logical LANs using IP
alias) behind the XMG can communicate with three distinct WAN networks.
192.168.1.13
192.168.1.10
192.168.1.11
192.168.1.12
SA
192.168.1.10
SA
IGA1
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
NAT Table
WAN
LAN
Inside Local
Address (ILA)
Inside Global
Address (IGA)
Содержание XMG3512-B10A
Страница 14: ...14 PART I User s Guide ...
Страница 23: ...Chapter 1 Introducing the XMG XMG3512 B10A User s Guide 23 Figure 8 Wall Mounting Example ...
Страница 33: ...Chapter 3 Quick Start XMG3512 B10A User s Guide 33 Figure 16 Quick Start Result Summary ...
Страница 56: ...56 PART II Technical Reference ...
Страница 139: ...Chapter 10 Quality of Service QoS XMG3512 B10A User s Guide 139 Figure 71 Classification Setup Add Edit ...
Страница 249: ...249 PART III Appendices Appendices contain general information Some information may not apply to your device ...
Страница 279: ...Appendix D Legal Information XMG3512 B10A User s Guide 279 Environmental Product Declaration ...