Votifier is a Bukkit plugin whose purpose is to get notified (aka votified) when a vote is made on a Minecraft server list for the server. Votifier creates a lightweight server that waits for connections by a Minecraft server list and uses a simple protocol to get information about that vote. Votifier is and always will be open-source.

Source : Bukkit.org

We are going to see in this guide how to install it from the auto-installer and how to test it. 

Make sure that you have Bukkit or Spigot installed as server version. 

Port range between 31000 and 32500.

STEPS: 

1. Go to the "Plugins" menu and search for Votifier.

2. Install the latest available version.

3. Then check the logs file to see if the plugin works fine during the server starts. 

4. Restart the server to create plugin's config file. 

5. Go the "FTP/MySQL" menu in the following directory: plugins/votifier/config.yml

6. Open the config.yml with the editor (pen style button).

7. In the editor, on the first line, put your server's IP, host: 198.27.83.113, in the second line use a port between 31000 and           32500. I have chosen port: 31200.

8. Then before quitting the editor, click on the green arrow button to save changes then RESTART the server. 

Now we are going to recover the Public key before testting the connection. 

9. From the "FTP/MySQL" menu recover your FTP credentials. 

10. To connect enter the address, user and password in Filezilla, then click on the "Quickconnect" button. 

11. From Filezilla, open the file in the plugins/rsa/public.key, make a right click and View/Edit.

Use this link to connect to the Votifier online test web page. 

12. Write your server's IP: 198.27.83.113

13. Write the Votifier's port: 31200

14. Copy the public key and paste it, in the server. 

15. Click on Test. 

16. You can see 'Success', so your Votifier's plugin is accessible for the external connection. 

Check the awesome tutorial on Votifier made by RyanGamerZ.