This is the first post in a series of posts providing step-by-step instructions that need to be followed in order to solve the labs proposed by Wendell Odom, the author of the books:

1. CCNA 200-301 Official Cert Guide, Volume 1

2. CCNA 200-301 Official Cert Guide, Volume 2

If you want to follow along, you can find the lab requirements and the .pkt file on Wendell’s blog.

You can download the Packet Tracer from Cisco Networking Academy.

In this lab, we need to configure PAT (Port Address Translation) on a Cisco router.

These are the steps we need to take:

1. Identify the hosts for which port address translations should take place (In our lab these are S1, S2 and S3).
2. Configure a NAT pool on R1.
3. Configure PAT on R1.
4. Configure a static route on R2.
5. Check that PAT is working as intended.

Check that the initial configuration is in place

Here is the network diagram used in this lab:

In the first step, I will check the initial configuration of the routers.

Configure the numbered access list (ACL) on router R1

In order to identify the hosts for which the address translations should take place, we need to configure a numbered access list on R1.

access-list 1 permit 192.168.100.64 0.0.0.63

Configure a NAT pool on router R1

In order to configure the NAT pool, we need to use the below command:

ip nat pool nat_pool 10.15.20.130 10.15.20.130 netmask 255.255.255.255

Configure PAT on router R1

Now, we need to configure the PAT on the Cisco router R1, and specify the inside and outside interfaces for which PAT should be performed.

ip nat inside source list 1 pool nat_pool overload

# under interface gig0/1
ip nat inside 

#under interface gig0/2
ip nat outside

Configure static route on router R2

Next, we need to configure the static route on R2 for the returning traffic. Without this route, there will be no communication between PC S1 and the Router R2.

ip route 10.15.20.130 255.255.255.255 172.16.100.1

After configuring the static route, we need to verify that it was added to the routing table.

show ip route

Check that PAT is working as intended

The last step is to verify the connectivity and ensure that PAT is working as expected.

ping 172.16.100.2

Now, we need to check if there are any translations on the router R1.

show ip nat translations
show ip nat statistics
show ip access-lists 

I hope you find this post helpful.

If you struggle to configure PAT, share your issue in the comments and I will try to help you.