Cisco Certified Internetwork Expert (CCIE) Practice Test

Which command allows for dynamic NAT configuration on a Cisco router?

1. ip nat inside source list

2. ip nat outside source

3. ip nat inside

4. ip nat pool

The correct answer is: ip nat inside source list

The command that facilitates dynamic NAT configuration on a Cisco router is "ip nat inside source list." This command specifies an access control list (ACL) that identifies the internal IP addresses that will be translated to the public IP addresses. By using this command, the router can dynamically map multiple internal addresses to a pool of public addresses based on the rules defined in the ACL. When dynamic NAT is configured, routers provide a way for internal devices to communicate with external networks (like the Internet) by translating their private IP addresses into public IPs as needed. The command indicates the internal network that needs NAT, allowing for the dynamic allocation of the public addresses from the pool. In contrast, the other command options serve different purposes within NAT configuration. While "ip nat outside source" is related to static NAT configurations or configuring NAT for traffic going to an outside source, "ip nat inside" merely indicates which interfaces are considered part of the inside network without specifying dynamic NAT. Similarly, "ip nat pool" is used to define a range of public IP addresses available for NAT translations but does not configure the actual mapping process. Thus, "ip nat inside source list" is specifically the command that initiates the dynamic translation process by referencing the ACL that identifies the traffic