Minecraft server in a FreeBSD Jail

You may have no interest in the game Minecraft, but that won’t stop people asking you to set up a server. Having read about how to do this on various forums and Minecraft fan sites (e.g. this one) I came to the conclusion that no one knew how to do it on current FreeBSD. So here is how you do it, jailed or otherwise.

First off, there isn’t a pre-compiled package. The best way to install it is from the ports, where it exists as /usr/ports/games/minecraft-server

Be warned – this one’s a monster! Run “make config-recursive” first, or it’ll go on stopping for options all the way through. Then run “make install”. It’s going to take quite some time.

The first configuration option screen asks if you want to make it as a service or stand-alone. I picked “service”, which sets up the start-up scripts for you but doesn’t actually tell you it’s done it. It does, however, stop it trying to run in graphics mode on your data centre server so I’m not complaining too much.

The good news is that this all works perfectly in a jail, so while it’s compiling (it could be hours) you can set up the required routing, assuming you’re using an internal network between jails – in this case Using pf this will look something like:

scrub in all
nat pass on $extinterface from to any -> $externalip
rdr pass on $extinterface proto tcp from any to $externalip port 25565 -> $minecraft
rdr pass on $extinterface proto tcp from any to $externalip port
{19132,19133,25565} -> $minecraft

And that’s it. You’re basically forwarding on TCP and three UDP ports. If you’re not using a jail, you obviously don’t need to forward anything. For instructions on setting up jails properly, see here, and for networking jails see elsewhere on this blog.

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One thing that’s very important – this is written in Java, so as part of the build you’ll end up with OpenJDK. This requires some special file systems are mounted – and if you’re using a jail this will have to be in the host fstab, not the jails!

# Needed for OpenJDK
fdesc /dev/fd fdescfs rw 0 0
proc /proc procfs rw 0 0

If you’re using a jail, make sure the jail definition includes the following, or Java still won’t see them:


Once you’ve finished building you might bet tempted to follow some of these erroneous instructions in forums and try to run “minecraft-server”. It won’t exist!

To create the basic configuration files run “service minecraft onestart”. This will create the configuration files for you in /usr/local/etc/minecraft-server. It will also create a file called eula.txt. You need to edit this change “eula=false” to “eula=true”.

You can make the minecraft service run on startup with the usual “minecraft_enable=yes” in /etc/rc.conf

And that’s really it. There are plenty of fan guides on tweaking the server settings to your requirements, and they should apply to any installation.

This assumes you’re handy with FreeBSD, understand jails and networking; if you’re not so handy then please leave a comment or contact me. Everyone has to start somewhere, and it’s hard to know what level to pitch instructions like this. Blame me for assuming to much!

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