Cisco Certified Network Associate (CCNA) Practice Exam

Which command is used to configure dynamic NAT?

1. (config)#ip nat pool POOL NAME FIRST PUBLIC IP ADDRESS IN POOL

2. (config)#ip nat source static PRIVATE IP ADDRESS AND PUBLIC IP ADDRESS

3. (config)#mac access-list extended LIST NAME

4. (config)#interface INTERNAL INTERFACE

The correct answer is: (config)#ip nat pool POOL NAME FIRST PUBLIC IP ADDRESS IN POOL

The command to configure dynamic NAT involves defining a pool of public IP addresses that can be used as translations for private IP addresses. The command includes specifying a name for the NAT pool followed by the first public IP address in that pool. This setup allows for the dynamic mapping of private addresses to these public addresses on a one-to-many basis, enabling multiple devices within a private network to share a smaller number of public IP addresses. By establishing a NAT pool, the router understands which public addresses are available for outbound traffic initiated from devices within the internal network. This is crucial in scenarios where the internal network has more devices than available public IP addresses, as dynamic NAT efficiently allocates addresses as needed. The other commands do not directly pertain to configuring dynamic NAT. The command that specifies a static NAT entry involves a one-to-one mapping of a private IP to a public IP rather than a pool. The command related to an access-list focuses on controlling traffic rather than translating IP addresses, and configuring an interface does not in itself specify any NAT behavior without additional commands. Thus, the configuration that establishes a NAT pool is essential for implementing dynamic NAT.