Tag Archives: nat

What is N.A.T. (Network Address Translation)

Here is another additional resource from my CCENT and CCNA books!

Cisco Learning Network Store home page

“New” NAT on the ASA – Object NAT/PAT with Manual Config

There are so many variations that are possible with NAT now – and I am just talking in the “new rules”. In this post, lets just review one. We will do dynamic NAT with a PAT backup using network objects. We will provide the NAT instructions manually instead of inside an object.

Our topology is as follows:


Our objective here is as follows:

  • Configure NAT so that hosts on the inside network attempting to reach the outside network are translated using the pool to 103. We need to use the interface IP address as a PAT backup. The NAT configuration must be manual.

My first step is to create my network objects:

object network 192INSIDE
object network POOL1

Verification of this step is show run object.

Now I am ready for the manual NAT:

nat (inside,outside) source dynamic 192INSIDE POOL1 interface

The above command is made VERY easy thanks to context-sensitive help.

For verification – we do not even need to leave the ASA thanks to Packet Tracer!

packet-tracer input inside tcp 1027 23
Phase: 4      
Type: NAT
Result: ALLOW
nat (inside,outside) source dynamic 192INSIDE POOL1 interface
Additional Information:
Dynamic translate to
input-interface: inside
input-status: up
input-line-status: up
output-interface: outside
output-status: up
output-line-status: up
Action: allow

Of course, we can always create traffic through the ASA and view the translation. Here I telnet through from R3 on the inside to R4 on the outside. We confirm out configuration and that traffic is matching it:

ASA1# show nat
Manual NAT Policies (Section 1)
1 (inside) to (outside) source dynamic 192INSIDE POOL1 interface  
    translate_hits = 6, untranslate_hits = 6

Of course I will be back with plenty of other “new” NAT sample configurations and verifications for you.