350-401 Question 194
Select 4A network engineer is tasked with configuring NAT Overload (PAT) on a Cisco router to allow multiple internal devices to share a single public IP address for outbound internet access. The internal network uses the 192.168.1.0/24 subnet, and the public IP address assigned to the router is 203.0.113.5. Which configuration commands should the engineer use to achieve this?
- A
ip nat inside source list 1 interface GigabitEthernet0/0 overload
- B
access-list 1 permit 192.168.1.0 0.0.0.255
- C
interface GigabitEthernet0/0 ip nat outside
- D
interface GigabitEthernet0/1 ip nat inside
- E
ip nat inside source static 192.168.1.10 203.0.113.5
Show answer and explanation
Correct answers: A, B, C, D
Explanation
To configure NAT Overload (PAT) on a Cisco router, the engineer must first define an access list to identify the internal subnet requiring NAT. Next, the internal (inside) and external (outside) interfaces must be configured for NAT. Finally, the 'ip nat inside source' command is used with the 'overload' keyword to enable PAT, allowing multiple devices to share a single public IP. Static NAT is unnecessary for this scenario, as PAT is required for dynamic translations.
- A. Correct.
This command enables NAT Overload (PAT) by specifying the source list (access-list 1) and the public-facing interface (GigabitEthernet0/0) for the translation. The 'overload' keyword ensures multiple internal devices can share the same public IP.
- B. Correct.
This command creates an access list to identify the internal subnet (192.168.1.0/24) that requires NAT. It allows traffic from this subnet to be translated.
- C. Correct.
This command configures the public-facing interface (GigabitEthernet0/0) as the NAT outside interface, which is required for NAT to function.
- D. Correct.
This command configures the internal-facing interface (GigabitEthernet0/1) as the NAT inside interface, allowing it to be part of the NAT process.
- E. Incorrect.
This command is used for static NAT, translating a single internal IP address to a single public IP address. It does not configure NAT Overload (PAT) and is not relevant to the scenario.