Wireless/Redundant Edge Services xl Module Management and Configuration Guide WS.02.xx and greater

Table Of Contents
8-1
8
Configuring Network Address Translation
(NAT)
Contents
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3
Translating Between an Inside and an Outside Network . . . . . . . . . . . 8-3
Local and Global Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4
NAT Implementation Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
Dynamic, or Many-to-One, NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
Dynamic NAT for Wireless Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5
Dynamic NAT for Wired Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
Port Address Translation for Dynamic NAT . . . . . . . . . . . . . . . . . . 8-7
Static, or One-to-One, NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-8
Static NAT on Destination Addresses . . . . . . . . . . . . . . . . . . . . . . . 8-8
Using Port Forwarding with Static Destination NAT . . . . . . . . . 8-10
Static NAT on Source Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . 8-12
Understanding Local and Global Addresses . . . . . . . . . . . . . . . . . . . . 8-12
Planning the NAT Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-14
Consider Your Company’s Requirements for NAT . . . . . . . . . . . . . . . 8-14
Record Necessary IP Addresses and Select the NAT
Implementation Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-15
Planning the Configuration for Dynamic NAT . . . . . . . . . . . . . . . 8-16
Planning the Configuration for Static NAT . . . . . . . . . . . . . . . . . . 8-17
Configuring Standard ACLs for Dynamic NAT . . . . . . . . . . . . . . . . . . . . . . 8-20
Configuring NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-22
Defining Interfaces as Outside or Inside . . . . . . . . . . . . . . . . . . . . . . . 8-22
Configuring Dynamic NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-24