Configuring Dynamic NAT: One Private to One Public Address Translation


For a complete configuration of NAT/PAT with a diagram for visual assistance, see the sample configuration at the end of this chapter.

Step 1: Define a static route on the remote router stating where public addresses should be routed.

ISP(config)#ip route s0/0

Informs the ISP router where to send packets with addresses destined for

Step 2: Define a pool of usable public IP addresses on your router that will perform NAT.


Private address will receive first available public address in pool

Corp(config)#ip nat pool scott netmask

Defines the following:

  • Name of pool is scott (The name of the pool can be anything.)

  • Start of pool is

  • End of pool is

  • Subnet mask is

Step 3: Create an ACL that will identify which private IP addresses will be translated.

Corp(config)#access-list 1 permit


Step 4: Link the access control list (ACL) to the pool of addresses. (Create the translation.)

Corp(config)#ip nat inside source list 1 pool scott

Defines the following:

  • The source of the private addresses is from ACL 1

  • The pool of available public addresses is named scott

Step 5: Define which interfaces are inside (contain the private addresses).

Router(config)#int fa 0/0


Router(config-if)#ip nat inside

You can have more than one inside interface on a router. Addresses from each inside interface are then allowed to be translated into a public address

Step 6: Define the outside interface (the interface leading to the public network).

Router(config)#int s 0/0


Router(config-if)#ip nat outside


CCNA Self-Study(c) CCNA Portable Command Guide
CCNA Portable Command Guide
ISBN: 1587201585
EAN: 2147483647
Year: 2006
Pages: 261
Authors: Scott Empson

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