NAT (PAT)

1. PAT (NAT Overloading) (many-to-one mapping)

1.1. Configure a standard access list to define what internal traffic will be translated

1.1.1. RouterA(config)# access-list 1 permit 192.168.0.0 0.0.0.255

1.2. Link the access list to the interface to be used for PAT

1.2.1. RouterA(config)# ip nat inside source list 1 interface fa0/0 overload

1.3. Define interfaces as either inside or outside

1.3.1. R0uter(config-if)#ip nat inside (or ip nat outside)

2. NAT terms

2.1. Inside local address

2.2. Inside global address

2.3. Outside local address

2.4. Outside global address

3. Static NAT (one-to-one mapping)

3.1. Define the router’s interfaces as inside or outside:

3.1.1. R0uter(config-if)#ip nat inside (or ip nat outside)

3.2. Define static mapping between the inside address and the outside address:

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

4. Dynamic NAT (one-to-one mapping)

4.1. Define a pool of addresses (public IP) to be used for dynamic NAT allocation

4.1.1. Router(config)#ip nat pool pool_name start_ip end_ip { netmask netmask | prefix-length prefix-length }

4.2. Configure a standard access control list to define what internal traffic will be translated

4.2.1. Router(config)#access-list access-list-number permit source [source-wildcard]

4.3. Link the access list to the NAT pool

4.3.1. Router(config)#ip nat inside source list access-list-number pool pool_name