// modpack server guide
SkyFactory 4 server hosting & setup guide
A SkyFactory 4 server needs Java 8 and about 6.5–7.5 GB of RAM for up to 3 players.
Darkosto's classic skyblock pack on Forge 1.12.2: grow resources on Sky Orchards trees instead of sieving, pick from over 30 world types, and unlock mods and items through the optional prestige system.
Pack details checked by hand against SkyFactory 4 on CurseForge on October 5, 2026.
SkyFactory 4 is a Forge modpack for Minecraft 1.12.2 with 202 mods. We'd pick our Premium plan (8 GB) for it.
- SkyFactory 4's multiplayer guide sets the world type in server.properties before the first start. For the classic start use generator-settings={"Topography-Preset":"Sky Factory 4"} and level-type=DEFAULT; the guide lists the settings for the other 30-plus world types.
- Players get their own island with /topography island new <player>, and /topography island home <player> takes them back to it.
- To use prestige on a server, set B:"Prestige Enabled Default"=true in prestige.cfg. The guide says to make this change again after every server update, and warns that the server has to restart once all players vote to close the Parabox loop.
- Players who want to share advancement progress can team up with /together invite <player>, from the Together Forever mod.
- SkyFactory 4 hasn't been updated since version 4.2.4 in December 2021, so its server files won't change.
Quick facts
| Loader | Forge |
|---|---|
| Minecraft versions | 1.12.2 |
| Java needed | Java 8 for Minecraft 1.12.2 Java version chart. |
| Mods | 202 modsThe number of mods CurseForge lists for the pack, client-side ones included. |
| RAM | About 6.5–7.5 GB for 1–3 playersBy player count. |
| Downloads | 14,114,441 on CurseForgeAs of October 5, 2026. |
| Latest version | December 13, 2021 (version 4.2.4)The newest version when we checked on October 5, 2026. |
| Official server files | Download pagePublished next to most versions on CurseForge, for example SkyFactory-4_Server_4_2_4.zip for version 4.2.4. |
| Where to get it | SkyFactory 4 on CurseForge |
| Tags | quests, tech, skyblock, magic |
SkyFactory 4 server files
SkyFactory 4's authors publish official server files. Published next to most versions on CurseForge, for example SkyFactory-4_Server_4_2_4.zip for version 4.2.4. Get the official server files.
Use the server files for the exact version your players install: a server and client on different pack versions won't connect.
How much RAM does a SkyFactory 4 server need?
| Players online | RAM | DSN plan |
|---|---|---|
| 1–3 players | About 6.5–7.5 GB | Premium (8 GB) |
| 4–8 players | About 7.5–9 GB | Heavy (12 GB)Premium (8 GB) can do if players stay close. |
| 9–15 players | About 8.5–11 GB | Heavy (12 GB) |
Estimated from 202 mods with our RAM calculator, not measured: low end if players stay together, high end if they spread out.
Set Java's heap (-Xmx) 10–15% under the RAM you have, about -Xmx7000M on 8 GB. Forge 1.12.2 takes it in the java command (-Xmx), usually in the start script. RAM guide.
SkyFactory 4 server requirements
| Java | Java 8 |
|---|---|
| Loader | Forge for Minecraft 1.12.2 |
| CPU | Fast single-core speed (one main thread). With 202 mods, the first start takes minutes. |
| RAM | About 6.5–11 GB for 1–15 players (table above) |
| Disk | The server files, a growing world and backups |
| Network | TCP port 25565 open to players |
Recommended plan
Our pick for SkyFactory 4
Premium
8 GB RAM · planned launch price $30/month
The authors don't publish RAM advice; CurseForge lists 202 mods for the pack and a sky world starts small, so 8 GB suits a small group.
Ordering is closed until we relaunch. We aren't taking orders or payments while we move to new hardware. Join the launch list and we'll email you when Premium servers open.
Running it for a bigger group or a public server? Go up to Heavy (12 GB, $42/month). Not sure? Email hello@dsnservers.com.
Planned launch price in USD, billed monthly once ordering opens, with a 7-day refund window.
How to make a SkyFactory 4 server on your own PC
What's specific to SkyFactory 4, step by step. The full walkthrough for any pack: how to make a modded Minecraft server.
- Install Java 8.
Check with
java -version. Java version chart. - Get the server files.
Download the official server files for the version your players use and unzip them into an empty folder. Follow the readme that comes with them.
- Start it and accept the EULA.
Run the start script in the server files, or
java -jaron the Forge jar the installer made, then seteula=trueineula.txtif you accept Mojang's EULA (EULA step). With 202 mods, the first start takes minutes. - Set the RAM with
-Xmx, sized from the table above. - Let friends connect: forward TCP 25565, or use a tunnel or host behind CGNAT (can't connect?).
Or run SkyFactory 4 on DSN
Once we relaunch (join the launch list), on DSN you'd install SkyFactory 4 from the panel's CurseForge modpack installer, pick Java 8 on the Startup tab and accept the EULA in the console. No port forwarding.
How to play SkyFactory 4 with friends
Each player installs SkyFactory 4 with the CurseForge app or Prism Launcher, the same version as the server, and adds the server's address under Multiplayer.
Different versions of SkyFactory 4 on the server and a client show up as Mismatched mod channel list or mod rejections. Why friends can't join, timeouts included.
Lag and performance on SkyFactory 4
Can't keep up! Is the server overloaded? means ticks take longer than 50 ms; more RAM won't fix that once SkyFactory 4 has enough (tick lag guide). For SkyFactory 4:
- Distances:
view-distance=8inserver.properties. - Pre-generate: with a pregeneration mod built for 1.12.2, before people explore.
Common SkyFactory 4 crashes
What a Forge 1.12.2 server running SkyFactory 4 hits most. For any other error, paste the log into the free crash log analyzer.
- Wrong Java version. Forge for 1.12.2 won't start on anything newer than Java 8, and stops with
ClassCastException: class jdk.internal.loader.ClassLoaders$AppClassLoader cannot be cast to class java.net.URLClassLoader. Java version fix. - Out of memory. SkyFactory 4 (202 mods) needs about 6.5–7.5 GB for 1–3 players;
java.lang.OutOfMemoryErrormeans it ran out. Out-of-memory fix. - Client-only mod on the server. This one shows up when the mods folder is copied from a player's game instead of installed as a server. Check a mods list with the client-or-server-side checker. Client-only mod fix.
- After adding or updating a mod. Mods you add to SkyFactory 4 by hand usually crash it with a missing dependency:
net.minecraftforge.fml.common.MissingModsExceptionnames the mod. - Ticking entity or block entity. The crash report names it and gives its coordinates. Ticking entity fix.
Updates and support
Before moving SkyFactory 4 past version 4.2.4, back up the world: see updating a modpack server without losing your world.
Bugs in SkyFactory 4 itself go to its authors: issue tracker and wiki. Server problems on DSN: hello@dsnservers.com or Discord.
Packs like SkyFactory 4
More: all modpack guides and how to make a modded server.
Run SkyFactory 4 on DSN when we relaunch.
Our pick, Premium: 8 GB, planned at $30/month.
DSN Servers isn't affiliated with SkyFactory 4 or CurseForge. We wrote the summary and checked the pack's facts by hand on October 5, 2026. Sources: curseforge.com, curseforge.com (2), curseforge.com (3), curseforge.com (4), api.cfwidget.com, github.com.