Players have to enter a password before they can connect to the server or even appear on the world. The password can easily be changed in the config file and can be up to 128 characters long. Optionally, players that are whitelisted, operators, or have the password.bypass permission don't have to enter the password when joining.
Preview the default config.yml
password: changeme
# Weather operators have to enter the password when joining.
operator_bypass: true
# Weather whitelisted players have to enter the password when joining.
whitelist_bypass: false
# Whitelisted players inactive for the specified number of days have to re-enter the password.
whitelist_bypass_expiration:
enabled: false
days: 14
# Whether players should be whitelisted when entering the password.
auto_whitelist: false