Configure NAT - GNS3 Lab

Hi ! everyone on today we are going to learn about how to configure nat using packet tracer which is given below.

Staic NAT
R0#configure terminal
R0(config)#int loopback0
R0(config-if)#ip address 10.0.0.1 255.0.0.0
R0(config-if)#ip nat inside

R0(config-if)#int f0/0
R0(config-if)#ip address 200.0.0.1 255.255.255.0
R0(config-if)#no shutdown
R0(config-if)#ip nat outside
R0(config-if)#exit

R0(config)#ip nat inside source static 10.0.0.1 200.0.0.2

R1#config terminal
R1(config)#int f0/0
R1(config-if)#ip address 200.0.0.10 255.255.255.0
R1(config-if)#no shutdown

R0#show ip nat translations

we want to test our NAT configuration we have to ping from R0’s loopback interface by using the ping extended command:

We can use the extended ping command by typing only “ping” at the privileged mode, specify the “target IP address” and type “y” at the “Extended commands” and specify the “source address or interface” 

To approve NAT works well we can disable static NAT with the following command

R0(config)#no ip nat inside source static 10.0.0.1 200.0.0.2

Now if we want to use the extended ping command (without NAT configured) this will be the results shown:

Thus, We can't ping from the loopback interface as shown in above screenshot.

Dynamic NAT

RouterA(config)# access-list 1 permit 192.168.0.0 0.0.0.255
RouterA(config)# ip nat pool PoolforNAT 200.23.123.6 200.23.123.10 netmask 255.255.255.0
RouterA(config)# ip nat inside source list 1 pool PoolforNAT

RouterA(config)# int loopback0
RouterA(config-if)# ip nat inside

RouterA(config-if)# int fa0/0
RouterA(config-if)# ip nat outside

Configure PAT (NAT Overload)

> Configure a standard access list to define what internal traffic will be translated
> Link the access list to the interface to be used for PAT
> Define interfaces as either inside or outside

PAT router commands
RouterA(config)# access-list 1 permit 192.168.0.0 0.0.0.255
RouterA(config)# ip nat inside source list 1 interface fa0/0 overload

RouterA(config)# interface fa0/0
RouterA(config-if)# ip nat outside

RouterA(config-if)# interface loopback0

RouterA(config-if)# ip nat inside