How to configure Static NAT in Cisco IOS Routers – Part 2

We discussed NAT Overloading in the Part-1 of our Cisco IOS NAT configuration here

Here, we will configure a Static NAT on Cisco IOS Routers. Static NAT is rather straightt forward as it is a one to one NATing between IP addresses as against the NAT Overloading or the Dynamic NAT where the IP addresses from the inside are NATed to a pool of IPs.

1. NAT inside interface

Enable an interface on the router with an IP Address and mark it as nat inside interface. This is the interface that connects to your internal private network

WANRouter(config)# int fastethernet0/1

WANRouter(config-if)# ip address 192.168.1.1 255.255.255.0

WANRouter(config-if)# ip nat inside

2. Enable NAT outside interface

WANRouter(config)# int serial0/0/0

WANRouter(config-if)# ip address 100.100.100.100 255.255.255.0

WANRouter(config-if)# ip nat outside

Instruct Router to NAT the Source IP Address to that of a NATed IP.

WANRouter(config)# ip nat inside source static 10.1.1.11 172.1.1.11

WANRouter(config)# ip nat inside source static 10.1.1.12 172.1.1.12

WANRouter(config)# ip nat inside source static 10.1.1.13 172.1.1.13

Where 10.1.1.x IPs are NATed to 172.1.1.x

The syntax is

ip nat inside source static x.x.x.x y.y.y.y

That sets up the Static NATs. These can co exist along with NAT Overloading or Dynamic NATs.

To check the NAT Status and Statistics

WANRouter# show ip nat statistics

To see the active translations

WANRouter# show ip nat translations