// guides

Modded Minecraft server guides

Everything we’ve written about running a modded Minecraft server: setting one up, keeping it updated, choosing Java and RAM, and fixing the crashes people hit most. Written for Forge, NeoForge and Fabric, and checked against each project’s own docs and files.

Updated October 2026  ·  Java Edition

Setting up and updating

• How to make a modded Minecraft serverServer files from CurseForge or Modrinth, the right Java, the EULA, RAM in user_jvm_args.txt, port 25565, and getting friends connected.
• Making a server for a modpack with no server packBuild one from the .mrpack or CurseForge zip, and leave out client-only mods without breaking dependencies. Worked example: Cobbleverse.
• Updating a modpack without losing your worldWhat to keep, what to replace, missing registry entries, and how to roll back.

Java, RAM and location

• Which Java version does my Minecraft server need?The Java for every Minecraft version up to 26.x, what class file versions mean, and the Java for every modpack we cover.
• How much RAM a modded server needsRAM by pack size and player count, and why single-core CPU speed matters more.
• Server location and pingHow much ping distance adds, how to test a host before you pay, and where DSN will host when it relaunches.

Loaders, packs and tools

• NeoForge server setupInstalling a NeoForge server, Java by version, Forge and Fabric mod support, and the NeoForge packs we’ve checked.
• Cobblemon server setupCobblemon modpacks compared for a server, with RAM by group size, setup and config.
• Client-side or server-side? Mod checkerPaste a mod list to see which mods belong only on players’ PCs.
• Crash log analyzerPaste a crash report or latest.log and get the cause and the fix.

Crash guides

Not sure which one you have? Paste your log into the free crash log analyzer above and it will tell you.

• Wrong Java version“Unsupported class file major version” and “compiled by a more recent version of the Java Runtime”.
• Out of memory“java.lang.OutOfMemoryError: Java heap space”.
• Client-only mod on the server“Attempted to load class net/minecraft/client/Minecraft for invalid dist DEDICATED_SERVER”.
• Missing mod dependency“requires … which is missing!” and “Missing or unsupported mandatory dependencies”.
• Wrong mod loader or Minecraft versionA Fabric mod on Forge, or a mod built for another Minecraft version.
• Mixin errors“Mixin apply failed” and “InvalidInjectionException”.
• Duplicate mods“Found duplicate mods” and “DuplicateModsFoundException”.
• EULA not accepted“You need to agree to the EULA in order to run the server”.
• Port already in use“**** FAILED TO BIND TO PORT!”.
• Server froze (watchdog)“A single server tick took 60.00 seconds”.
• Corrupt chunk or world data“Failed to read chunk” and damaged region files.
• Exception ticking entity“Exception ticking entity” and “Ticking block entity” crash loops.
• Can’t keep up! Is the server overloaded?Tick lag on a modded server: reading TPS and MSPT, and what actually helps.
• Friends can’t join“Mismatched mod channel list”, mod rejections, timeouts and port forwarding.

Modpack guides

Setup guides for over 100 modpacks, each with its Minecraft version, loader, Java version, RAM pick and common crashes: all modpack guides. Not sure which to run? See the best modpacks for multiplayer servers, grouped by play style with the RAM each needs for a small group.

Other games

• Project Zomboid: Build 42 servers and our waitlistHow a Build 42 dedicated server loads Workshop mods, Build 42 or legacy41, and moving from Build 41. We don’t sell Zomboid servers; the page has a waitlist.