How To: Minecraft Server Not Working - Why?

I love the game Minecraft especially when playing with friends on my Minecraft server. Minecraft servers are relatively easy to setup. There is plenty of documentation on the Minecraft wiki to explain how to get the Minecraft java executable to run.  However, this is a popular message among people who are starting their first server: 'My friends can't connect to my server?'.  This post aims to help people who have a server running except no one is able to connect. In the majority of cases this guide should help get you and your friends back Minecrafting again!

Port Forwarding
The first thing you need to take care of is port forwarding .  This means opening a port on your home network which allows Minecraft traffic to find your computer. Make sure you have allowed the Minecraft server through your computers firewall. Usually when you first start the server, a message pops up about allowing java access to your network – click allow. Otherwise, you can go into your firewall settings and add an exception as port 25565.

After that has been taken care of you need to allow traffic through your internet router. The port you need to open is: 25565.

My router showing the open port.

Everyone has a different router and this means I cannot explain exactly how to open the port on your router. However portforward.com explains how to do it on most routers.

At this point you should have successfully opened port 25565 through your firewall and router. You can check that it is successful by entering the port number on canyouseeme.org (make sure you do this while the server is running).

IP Address
"My Minecraft server was working but now no one can connect." - This could be because you have a dynamic IP address. Having a dynamically changing IP means that you could find your IP address one day and give it to your friend. The next day it could be a different address and your friend is no longer able to connect.

The best way around this is to set up an account with a DNS service like dyndns.org . This service assigns an address to your IP (eg. <your-minecraft-server>.dyndns.org). Simply sign up to a free account and add a hostname.

Next you need to download the Dynamic Update Client. This constantly updates your IP address with the hostname you created. It is pretty straightforward to install and set up. Once it is running it will constantly update your IP address. As a result you can give your friends this address you created and they will be able to connect every time!

Up-To-Date
If an update comes out for Minecraft, make sure that the server is the same version as the version that your friends have. Make sure you keep Up-To-Date!

Hopefully after following this guide, you will have gotten your Minecraft server running again. Of course there are many other problems that you could stop your friends connecting to your server.  If you have any other questions or suggestions, please let me know in the comments below or feel free to email me. I will probably update this post in future if the need arises.

Happy Minecrafting!