200-301 Question 360
Select 3A network engineer is tasked with configuring static NAT to allow an internal web server with the IP address 192.168.1.10 to be accessible from the internet using the public IP address 203.0.113.10. After configuring the NAT settings, how can the engineer verify that the NAT is working correctly?
- A
Use the 'show ip nat translations' command to confirm the mapping between the internal and external IP addresses.
- B
Ping the public IP address (203.0.113.10) from an external device to verify connectivity.
- C
Use the 'show ip nat statistics' command to check if NAT translations are incrementing.
- D
Configure a loopback interface with the public IP address to simulate the NAT behavior.
- E
Access the web server using the public IP address from an external device.
Show answer and explanation
Correct answers: A, C, E
Explanation
To verify that static NAT is working, the engineer should use tools like 'show ip nat translations' to confirm the mapping, check NAT statistics to ensure translations are occurring, and perform an actual test by accessing the internal resource (web server) using the public IP address from an external device. These methods together confirm that the NAT configuration is correct and operational.
- A. Correct.
The 'show ip nat translations' command displays the NAT table, allowing the engineer to verify the static NAT mapping between the internal and public IP addresses.
- B. Incorrect.
While pinging the public IP address may test basic connectivity, it does not confirm that the static NAT is working correctly for services like HTTP.
- C. Correct.
The 'show ip nat statistics' command provides information about NAT translations. If the NAT is configured and working correctly, the translation counters should increment.
- D. Incorrect.
Configuring a loopback interface with the public IP address is not a standard verification method for NAT and does not test external connectivity.
- E. Correct.
Accessing the web server using the public IP address from an external device is one of the most reliable ways to verify that the static NAT configuration is functioning correctly.