How to Host a Minecraft Modpack Server: Forge and Fabric Setup Guide

Setting up a modpack server is more involved than vanilla - but with the right steps, you can have it running in under 30 minutes.

Forge vs Fabric: Which Loader?

The modpack you want to run determines your loader. You don't get to choose.

• Forge/NeoForge: Feed The Beast (FTB), All The Mods (ATM), RLCraft, SevTech Ages, Create
• Fabric: Fabulously Optimized, Cobblemon, William Wythers Overhauled Overworld, some Create ports

Check the modpack's CurseForge or Modrinth page - it will clearly state which loader is required.

Setting Up a Forge Modpack Server

Step 1: Get the Server Files

Most modpacks provide a server pack download. On CurseForge or Modrinth, look for "Server Pack" or "Server Files" in the download options. This ZIP contains everything needed.

Step 2: Upload to Your Server

Extract the server pack locally, then upload everything to your server via FTP or the web file manager. The structure should include a forge-*.jar or run.sh, along with mods/, config/, and other directories.

Step 3: Configure Startup

Set your startup command to point to the Forge JAR with appropriate memory flags:

java -Xms8G -Xmx8G -jar forge-1.20.1-47.3.1.jar --nogui

On Space-Node's control panel, you configure the startup parameters in the server settings. Select the Forge JAR as the server file and set your memory allocation.

Step 4: Accept the EULA

On first run, the server generates eula.txt. Change eula=false to eula=true and restart.

Step 5: Configure Server Properties

Edit server.properties:

max-players=20
view-distance=8
simulation-distance=6
server-port=25565
difficulty=normal

Reduce view distance from the default 10 to 8 for modded - your TPS will thank you.

Setting Up a Fabric Modpack Server

Step 1: Install Fabric Server

Download the Fabric server installer from fabricmc.net. Run it or upload the resulting fabric-server-launch.jar.

Step 2: Add Mods

Upload all server-side mods to the mods/ folder. Client-only mods (shaders, HUDs) should NOT be on the server.

Step 3: Essential Server-Side Mods

Always include these Fabric server mods:

• Lithium - General server optimization
• Starlight - Lighting engine rewrite (massive performance gain)
• C2ME - Multi-threaded chunk generation
• FerriteCore - Memory optimization
• Krypton - Network stack optimization

Step 4: Same Configuration

Edit server.properties the same way as Forge. Accept EULA. Set memory flags.

Common Issues and Fixes

Server Crashes on Startup

• "java.lang.OutOfMemoryError" - Increase RAM allocation. Most modpacks need 6-12GB.
• "Mod X requires Mod Y version Z" - Dependency mismatch. Download the exact version specified.
• "Mixin apply failed" - Mod conflict. Remove the last mod you added and test.

Server Runs But Players Can't Join

• Ensure clients have the EXACT same mods and versions as the server
• Remove client-only mods from the server (minimap mods, shader mods)
• Check that the server port is open and reachable

TPS Drops After Playing

• Check Spark profiler for the worst offenders
• Common culprits: mob farms, automated systems, chunk loaders
• Reduce loaded chunks per player in server config

Player Distribution

Your players need the same mods installed client-side. Options:

1. CurseForge/Modrinth app: Players install the pack directly from the launcher
2. Custom launcher: Use packwiz or MCUpdater for custom modpack distribution
3. Manual ZIP: Distribute a client ZIP with instructions (least user-friendly)

For custom packs not on CurseForge/Modrinth, create a packwiz repository that players can import into Prism Launcher or MultiMC.

Performance Expectations

Modded Minecraft server performance on Space-Node's Ryzen 9 9950X servers:

The Ryzen 9 9950X's high clock speed is particularly helpful for modded, keeping up with the random memory access patterns and heavy tick load that modded Minecraft generates constantly.