Lab Objective:
The objective of this lab exercise is for you to learn and understand how to configure pool-based PAT.
Lab Purpose:
PAT configuration is a fundamental skill. PAT provides many-to-one translation using random port numbers. This means that multiple inside hosts can use the same outside address to communicate with external devices, while hiding their private IP addresses. Like dynamic NAT, PAT works in one direction only: from the inside to the outside. Interface-based PAT translates all private IP addresses to the outside interface on the router. As a Cisco engineer, as well as in the Cisco CCNA exam, you will be expected to know how to configure interface-based Port Address Translation.
Certification Level:
This lab is suitable for CCNA certification exam preparation
Lab Difficulty:
This lab has a difficulty rating of 8/10
Readiness Assessment:
When you are ready for your certification exam, you should complete this lab in no more than 10 minutes
Lab Topology:
Please use the following topology to complete this lab exercise:
Task 1:
Configure the hostnames on routers R1, R2 and Sw1 as illustrated in the topology.
Task 2:
Configure R1 S0/0 which is a DCE to provide a clock rate of 256Kbps to R2. Configure the IP addresses on the Serial interfaces of R1 and R2 as illustrated in the topology.
Task 3:
Configure VLAN 50 named NAT_VLAN on Sw1. Assign the FastEthernet0/2 interface on Sw1 to this VLAN. Also, configure R1 to allow Telnet access using a password of CISCO.
Task 4:
Configure interface VLAN 50 on Sw1 and assign it the IP address illustrated in the topology. The default gateway on Sw1 should be 10.2.2.2. Next, configure interface FastEthernet0/0 in R2 and assign it the IP address illustrated in the topology.
Task 5:
Test connectivity by pinging from R1 to R2 and pinging from R2 to Sw1. These should all be successful. However, since R1 does not know about the 10.2.2.0/27 subnet, Sw1 will not be able to ping R1 or vice versa.
Task 6:
Create an ACL to permit all IP traffic from the 10.2.2.0/27 subnet to the 192.168.254.0/29 subnet. You can create either a named or numbered ACL to complete this task.
Task 7:
Configure R2 F0/0 as the inside interface for NAT and S0/0 as the outside interface for NAT. Next, configure a pool called PAT-POOL to be used for PAT translation. This pool should have both a single starting and ending IP address of 192.168.254.4. Use the same subnet mask as that of S0/0 for this pool.
Task 8:
Configure PAT on R2 to translate traffic specified in the ACL configured in Task 6 to the pool named PAT-POOL. Telnet from Sw1 to R1. If you have configured PAT correctly, this should work. The same applies for ping from Sw1 or the Fa0/0 interface of R2 to R1.
Task 9:
Check the NAT translation table on R2 using the show ip nat translations command.