350-401 Question 196
Single answerYou are configuring PAT (Port Address Translation) on a Cisco router to allow multiple internal devices to access the internet using a single public IP address. After assigning an ACL to define the internal network (192.168.1.0/24), which set of commands will correctly configure PAT on the router?
- A
ip nat inside source list 1 interface GigabitEthernet0/1 overload
- B
ip nat inside source static 192.168.1.10 203.0.113.2
- C
ip nat inside source list 1 pool NAT_POOL overload
- D
ip nat inside source list 1 interface GigabitEthernet0/1
- E
ip nat inside source static tcp 192.168.1.10 80 203.0.113.2 8080
Show answer and explanation
Correct answer: A
Explanation
PAT allows multiple internal devices to share a single public IP address by assigning unique port numbers to each session. The correct command, 'ip nat inside source list 1 interface GigabitEthernet0/1 overload,' maps the internal devices defined in ACL 1 to the public IP of the interface while enabling port-based differentiation through the 'overload' keyword.
- A. Correct.
Correct. This command enables PAT by translating internal addresses from ACL 1 to the public IP address assigned to the GigabitEthernet0/1 interface, using port numbers to differentiate traffic.
- B. Incorrect.
Incorrect. This command configures static NAT for a single internal host, not PAT, and does not satisfy the requirement for multiple devices to share one public IP address.
- C. Incorrect.
Incorrect. This command uses a NAT pool for dynamic NAT, which is not required for PAT. PAT specifically uses a single public IP with port-based differentiation.
- D. Incorrect.
Incorrect. This command configures NAT without the 'overload' keyword, which is necessary for PAT to function.
- E. Incorrect.
Incorrect. This command configures static port forwarding for a single host and service, not PAT for multiple internal devices.