What is the function of the command #service password-encryption?

The command #service password-encryption serves the function of encrypting all plain text passwords in the device configuration. When this command is enabled on a Cisco router or switch, it ensures that any passwords in the configuration file are stored in an encrypted format rather than in plain text. This is an important security measure because it helps to protect sensitive information from being easily read by unauthorized users who may access the configuration.

By encrypting the passwords, it mitigates the risk of exposure in the event that the configuration file is viewed or downloaded, thus protecting user credentials and enhancing overall device security.

The other options do not accurately reflect the purpose of the command. Displaying current passwords, resetting user passwords, and setting password complexity requirements involve different commands and configurations altogether. Therefore, the focus on encrypting all plain text passwords clearly distinguishes the function of the #service password-encryption command.