Netherlock

Netherlock is a plugin that can lock the nether dimension either

manually

using
/netherlock lock
and
/netherlock unlock

automatically

either by using commands
/netherlock automode on/off
/netherlock setopen [time]
/netherlock setclose [time]
or by using the plugin's config file

localization

you can customise the messages that the plugin displays by modifying them in the config file