James Harper
How To Set Up a High-Performance Paper Server
If you’ve ever tried running your own Minecraft server, you know it’s not as simple as just clicking a couple of buttons. Sometimes, things go wrong — Java crashes, configs don’t load, port forwarding seems impossible, and you’re left scratching your head. Setting up a Paper server for version 1.21.6 isn’t insanely complicated, but there are a few tricks that can trip you up, especially if you’re not familiar with the command line or network configs. This guide aims to cut through the confusion, walk you through the essentials, and hopefully get you up and running with a stable multiplayer server that you and friends can hop onto without hiccups. By the end, you’ll have a decent grasp of managing your own server and tweaking it to your liking.
How to Fix Common Issues When Setting Up a Minecraft Paper Server for 1.21.6
Make sure Java is installed properly and the correct version is running
First off, Java is the backbone here. If Java isn’t installed or if you have an incompatible version, your server won’t even start, or worse, it crashes midway. On Windows, open Command Prompt and type java -version. You should see a line telling you what version is installed. Ideally, Java 17 or newer (JDK 17) is needed for Minecraft 1.21.6 — otherwise, the server might not run properly. If you get an error or a version earlier than 17, download the latest JDK from Oracle’s download page. On Mac/Linux, open Terminal and do the same test. Not sure why, but sometimes even if Java is installed, the PATH isn’t set right, and the server can’t find Java at all. Fix that by setting your environment variables or reinstalling Java.
Check your firewall rules and port forwarding — don’t skip this step
This one gets a lot of people. If your friends can’t connect or it looks like the server is just not reachable, it’s probably a network issue. On Windows, open PowerShell as admin and run:
New-NetFirewallRule -DisplayName "Minecraft Server" -Direction Inbound -Protocol TCP -Action Allow -LocalPort 25565
This opens the port in your Windows firewall. You can also check your firewall settings via Windows Defender Firewall in the control panel and ensure that inbound rules allow traffic on port 25565.
Now, if friends are outside your local network, you need to do port forwarding on your router. Access your router’s admin panel (usually through 192.168.1.1 or similar), find the port forwarding section, and forward port 25565 to your PC’s local IP address. Make sure your PC has a static local IP — otherwise, the forwarding might break after a reboot. You can set this up in your router’s DHCP settings or via your OS network settings. Sometimes, the tricky part is “wait, is my IP static or dynamic?” — because of course, Windows has to make it harder than necessary.
Clarify the startup script and check the server files
If the server won’t start or crashes straight away, double-check your start.bat file. It should read something like:
java -Xmx4G -jar paper-1.21.6.jar nogui
If you’re running on a machine with less RAM, bump -Xmx4G down to -Xmx2G or whatever fits. Also, make sure the jar filename matches exactly — if you downloaded a newer build, it might be paper-1.21.6-XYZ.jar. In that case, update the command accordingly.
After the first run, check the output logs in the console or the generated files in your folder. If you see errors related to Java or missing files, fix those before proceeding. Sometimes, the server needs to generate some initial files, and if a crash occurs, you might need to delete the eula.txt file, then re-run the start script to regenerate configs.
Accept the EULA and adjust server properties
When you first launch the server, it’ll stop and tell you to accept the EULA. Open eula.txt found in your server folder and change eula=false to eula=true. Save it, then run the server again.
Sometimes, settings in server.properties cause connectivity problems or lag. Open that file and tweak options like max-players, level-name, or online-mode. If players from outside your LAN can’t connect, check that online-mode is set to false (if you’re testing locally) or properly configured with your server’s IP if running in a real setup.
Allocate enough RAM, but don’t go overboard
Giving your server more RAM can help, especially if you run plugins or have many players. Check how much RAM your machine has in Task Manager or Activity Monitor. Then, edit your start.bat to set -Xmx and -Xms appropriately. For example, if you have 8GB RAM, try -Xmx4G. Keep in mind, allocating too much can cause stability issues, so don’t max out your system.
Run the server as administrator or with proper permissions
This is a sneaky trick. Sometimes, your server fails to bind to the port or write files because of launch permission issues. Running your start.bat as administrator (right-click > Run as administrator) can fix those hiccups. Also, ensure your user account has full write permissions to the server folder.
Test with a simple connection before adding plugins or fancy configs
Once the server’s up and running, connect to localhost or your local IP from your Minecraft client. If that works, try connecting with your public IP from another device outside your network. If that fails, double-check your port forwarding, firewall, and router settings. Sometimes, resetting your router or giving it a quick reboot helps clear up sticky NAT issues.
Summary
- Verify Java installation and version.
- Open port 25565 in Windows Firewall and your router.
- Check your start.bat script matches the downloaded jar file.
- Accept the EULA in eula.txt.
- Configure network settings properly for external access.
- Adjust RAM allocation based on your system.
- Run the server with admin rights if needed.
Wrap-up
Getting a Minecraft Paper server to work smoothly isn’t rocket science, but it does require paying attention to Java versions, network configs, and permissions. On a few setups, things might need a bit of patience or a second look, but overall, it’s doable. Once it’s stable, you’ll be able to run plugins, tweak gameplay, and host your friends without much fuss. Just remember, even after everything’s set, occasional hiccups with NAT or Java are normal — don’t get discouraged if it takes a few tries to get it perfect.
Frequently Asked Questions
How do I restart my server?
Just type stop in the server console — it gracefully shuts everything down. Then, double-click your start.bat again to relaunch it.
Can I run multiple servers on the same machine?
Yup, but you’ll need different folders, unique port numbers (change port in server.properties), and possibly different RAM allocations for each one. It’s a bit more work, but totally doable.
What are the best plugins for my Paper server?
Popular picks include EssentialsX (common commands and teleporting), WorldEdit (world editing), and GriefPrevention (protecting things). They add a lot of flexibility and fun, but watch out for plugin conflicts or compatibility issues after updating Java or server version.