What command is used to reset an interface to its default configuration on a Cisco router?

The command to reset an interface to its default configuration on a Cisco router is "default interface interface". This command is used in global configuration mode, where you specify the interface you want to reset, such as "default interface GigabitEthernet0/1".

When executed, it removes any configuration changes that have been made to the specified interface and resets it to the default settings defined by the device. This can include reverting properties such as the interface state, IP address assignments, and various other settings back to factory defaults.

This process is particularly useful for network administrators who want to clear custom configurations and start fresh without needing to manually erase each individual setting. The other commands listed do not fulfill this specific function of fully reverting an interface to its original default state.