Configuring Static And Dynamic Nat Translation; Network Address Translation Overview - Cisco Nexus 3548 Configuration Manual

Configuring Static and Dynamic NAT Translation

•
•
•
•
•
•
•
•
•
•
•
•
•
•
•

Network Address Translation Overview

Network Address Translation (NAT) enables private IP internetworks that use nonregistered IP addresses to
connect to the Internet. NAT operates on a device, usually connecting two networks, and translates private
(not globally unique) IP addresses in the internal network into legal IP addresses before packets are forwarded
to another network. You can configure NAT to advertise only one IP address for the entire network to the
outside world. This ability provides additional security, effectively hiding the entire internal network behind
one IP address.
A device configured with NAT has at least one interface to the inside network and one to the outside network.
In a typical environment, NAT is configured at the exit router between a stub domain and a backbone. When
a packet leaves the domain, NAT translates the locally significant source IP address into a globally unique IP
address. When a packet enters the domain, NAT translates the globally unique destination IP address into a
local IP address. If more than one exit point exists, NAT configured at each point must have the same translation
table.
NAT is described in RFC 1631.
Network Address Translation Overview, on page 91
Information About Static NAT, on page 92
Dynamic NAT Overview, on page 93
Timeout Mechanisms, on page 94
NAT Inside and Outside Addresses, on page 95
Pool Support for Dynamic NAT, on page 95
Static and Dynamic Twice NAT Overview, on page 96
Licensing Requirements for Static NAT, on page 96
Guidelines and Limitations for Static NAT, on page 97
Restrictions for Dynamic NAT, on page 98
Guidelines and Limitations for Dynamic Twice NAT, on page 98
Configuring Static NAT, on page 99
Configuring Dynamic NAT, on page 106
Information About VRF Aware NAT, on page 119
Configuring VRF Aware NAT, on page 119
Cisco Nexus 3548 Switch NX-OS Interfaces Configuration Guide, Release 9x
6
C H A P T E R
91