Cisco Certified Network Associate (CCNA) Practice Exam

Which of the following commands is executed to specify the NAT inside interface?

1. (config-if)#ip nat inside

2. (config-if)#ip nat outside

3. (config)#ip nat pool POOL NAME

4. (config)#access-list ACL NUMBER permit host

The correct answer is: (config-if)#ip nat inside

The command used to specify the NAT inside interface is indeed the one that begins with "ip nat inside." This command is essential in configuring Network Address Translation (NAT) because it designates an interface on a router as one that will handle private IP addresses, which are usually assigned to devices on an internal network. By marking an interface as the inside NAT interface, it tells the router that the traffic coming from this interface should be translated when it needs to access the outside network. This configuration is part of the NAT setup that ensures proper translation of addresses when packets leave the internal network toward the Internet or any external destination. Properly specifying the NAT inside interface is crucial for establishing the inner workings of NAT, as it defines which traffic will be processed for address translation. Other options provided do not play a role in identifying the NAT inside interface. For example, the command indicating "nat outside" configures an interface for the external side of NAT. The "ip nat pool" command is related to defining a range of addresses for NAT translations, and the access-list command pertains to creating and controlling access lists but does not directly specify NAT interfaces.