HostNameWhiteList

Note
As of 1.4, this is a universal plugin meaning you can use it with either BungeeCord or Bukkit.
To put it simply, you can place the jar in the BungeeCord plugins folder or the Bukkit plugins folder.

Description
This plugin creates a whitelist of host names that can connect to your servers. This plugin is useful to block other domains (i.e. unofficial domains that you don't have ownership of) that are linking to your server while also providing a helpful message to the end user that redirects them to the official address. This plugin may also be useful if you have changed your server IP and want to redirect your users to a new one.

Source Code
Github

Commands
Aliases: hostnamewhitelist, hnw

/hnw reload
- Reloads configuration
- permission: hostnamewhitelist.admin

Configuration

# Message that is displayed on the MOTD or when a player tries to connect
warning: '&cYou entered the wrong IP address, please use &3example.com &c instead'
# Block legacy players since we can't check which hostname they are connecting from
block-legacy: true
# Ignore hostname capitalization
ignore-case: true
# Players can only connect through the following host names
allowed-host-names:
    - 'localhost'

Screenshots