What command is used to clear dynamic NAT entries before the timeout has expired?

The command used to clear dynamic NAT entries before the timeout has expired is "clear ip nat translation." This command effectively removes the existing dynamic NAT translations in the NAT table, forcing the router to delete the current entries which can be helpful in scenarios where you want to immediately free up addresses or resolve issues with stale translations.

The "clear ip nat translation" command is particularly useful in dynamic NAT configurations where translations are created dynamically based on the IP address assignment. By using this command, administrators can manage the NAT entries actively and ensure that the translation pool has available entries when needed, enhancing network behavior and performance as traffic patterns change.

Other options serve different purposes: "show ip nat statistics" provides a summary and statistics of NAT translations but does not modify the entries, while "clear nat sessions" is not a standard command in Cisco IOS, and "reset ip nat" is also not a recognized command for clearing NAT translations. Thus, "clear ip nat translation" is the precise and effective command for the task at hand.