User guide

NAT support on AT-iMG Models Network address translation - NAT
4-135
iMG/RG Software Reference Manual (IPNetwork Functions)
• static NAT: defines a fixed address translation from the internal network to the external network
• dynamic NAT: translates from a pool of local IP addresses to a pool of global IP addresses
NAT provides a mechanism for reducing the need for globally unique IP addresses. It allows you to use
addresses that are not globally unique on your internal network and translate them to a single globally unique
external address
FIGURE 4-3 Address Conservation Using NAT
4.4.2 NAT support on AT-iMG Models
AT-iMG Models NAT module is designed to provide the following features:
• Global IP address pools
• Reserved mappings
• Application level gateways (algs)
NAT services are available between External security interface and Internal Security interfaces.
In order to access NAT services, the NAT module must be enabled between a a pair of interfaces by using the
NAT ENABLE command and assigning an arbitrary name to this relationship.
Note: Before enabling NAT, the Security module must be already enabled using SECURITY ENABLE
command.
See XREF_HERESecurity section for details regarding security interfaces.
Global IP Address Pools
A Global Address Pool is a pool of addresses seen from the external network. By default, each external inter-
face creates a Global Address Pool with a single address – the address assigned to that interface.
10.0.0.3
10.0.0.2
24.2.249.4
Unit
(Router with NAT)
10.0.0.4
10.0.0.1
Internet