Cisco's IOS commands are associated with fifteen different levels of privilege.

  • Level one is user mode; users can look at configurations but make no changes.
  • Level two is used with minimal access. Commands such as show, ping, and debug are used for monitoring and testing.
  • Level fifteen is the highest privilege mode; reload, erase NVRAM, erase flash, and shutdown are examples of level fifteen commands.

To customize privilege levels, use the privilege level configuration command.