PAT (NAT Overload)
Share this page:Port Address Translation (PAT) means using PORTS in order to NAT various Inside Local IPs to 1 Inside Global IP.
Step 1: Create an ACL with all the Inside Local addresses:
(config)#access-list 1 permit 10.2.2.0 0.0.0.7
Step 2: There are 2 ways to configure PAT, described in Steps 2.1 and 2.2:
Step 2.1:
- Create the Inside Global IP Pool of any addresses from the Link towards the other Router:
(config)#ip nat pool OVERLOAD 10.1.1.2 10.1.1.2 prefix-length 24
- Configure the NAT Overload with the defined pool:
(config)#ip nat inside source list 1 pool TASK2 overload
Step 2.2:
Configure the NAT to point to the Interface you need the traffic to go out from:
(config)#ip nat inside source list 1 interface s0/1/0.21
!!! The system adds “overload” argument:
(config)#do sh run | i nat inside
ip nat inside
ip nat inside source list 1 interface Serial0/1/0.21 overload