200-301 Question 358
Single answerA network administrator is configuring NAT on a router to allow internal devices with private IP addresses to access the Internet. The administrator needs to configure static NAT for a web server with an internal IP address of 192.168.1.10 so that it can be reached from the public IP 203.0.113.5. Which of the following commands will correctly configure this static NAT mapping?
- A
ip nat inside source static 192.168.1.10 203.0.113.5
- B
ip nat outside source static 192.168.1.10 203.0.113.5
- C
ip nat inside source static 203.0.113.5 192.168.1.10
- D
ip nat pool STATIC-NAT 192.168.1.10 203.0.113.5 netmask 255.255.255.0
Show answer and explanation
Correct answer: A
Explanation
Static NAT is used to create a one-to-one mapping between a private IP address and a public IP address. In this scenario, the correct command is 'ip nat inside source static 192.168.1.10 203.0.113.5', as it maps the internal private IP of the web server to the specified public IP. The 'inside' keyword indicates that the private IP is from the internal (LAN) network, and it is being translated to a public IP for external access.
- A. Correct.
This command correctly maps the internal private IP address (192.168.1.10) to the public IP address (203.0.113.5) using static NAT. The 'ip nat inside source static' syntax is used for this purpose.
- B. Incorrect.
The 'ip nat outside source static' command is used for external-to-internal NAT, which is not the case in this scenario. The web server resides inside the network.
- C. Incorrect.
This command incorrectly reverses the mapping, mapping the public IP to the private IP, which is not the intended configuration.
- D. Incorrect.
The 'ip nat pool' command is used for configuring a range of IP addresses for dynamic NAT or PAT, not for static NAT.