// modpack server guide

FTB Skies 2 server hosting & setup guide

An FTB Skies 2 server needs Java 21 and about 10–12 GB of RAM for up to 8 players.

FTB's skyblock pack for NeoForge 1.21.1, with custom mechanics, quests and progression that the players drive.

Pack details checked by hand against FTB Skies 2 on FTB on October 4, 2026.

By DSN Servers · Updated October 2026 · NeoForge · Minecraft 1.21.1 · Java Edition

FTB Skies 2 is a NeoForge modpack for Minecraft 1.21.1 with 436 mods, 406 of which run on the server. We'd pick our Heavy plan (12 GB) for it.

Quick facts

Loader	NeoForge
Minecraft versions	1.21.1
Java needed	Java 21 for Minecraft 1.21.1 Java version chart.
Mods	406 run on the server436 in the pack. The other 30 are client-only, and the server skips them. Counted from FTB's file list for version 1.23.0.
RAM	About 9–10 GB for 1–3 playersBy player count.
Downloads	574,017 on the FTB appAs of October 4, 2026.
Latest version	September 24, 2026 (version 1.23.0)The newest version when we checked on October 4, 2026.
Official server files	Download pageFTB publishes server files for every version on the pack's Versions tab and in its server files browser.
Authors' RAM advice	FTB's launcher setting for this pack is 8 GB recommended and 6 GB minimum, for the game.Source
Where to get it	FTB Skies 2 on FTB
Tags	skyblock, exploration, quests, magic, tech

FTB Skies 2 server files

FTB Skies 2's authors publish official server files. FTB publishes server files for every version on the pack's Versions tab and in its server files browser. 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 an FTB Skies 2 server need?

Players online	RAM	DSN plan
1–3 players	About 9–10 GB	Heavy (12 GB)
4–8 players	About 10–12 GB	Heavy (12 GB)
9–15 players	About 11.5–15 GB	Heavy (12 GB) if players stay closeMore than 12 GB if they spread out.

Estimated from 406 mods with our RAM calculator, set against the authors' own advice, not measured: low end if players stay together, high end if they spread out. What the authors say: FTB's launcher setting for this pack is 8 GB recommended and 6 GB minimum, for the game.

With 9–15 players spread across the map, FTB Skies 2 can need more than 12 GB, our biggest plan. A lower view distance and a pre-generated world help it fit; past that, a host with bigger plans is the better choice.

Set Java's heap (-Xmx) 10–15% under the RAM you have, about -Xmx10500M on 12 GB. NeoForge 1.21.1 reads it from user_jvm_args.txt: uncomment the -Xmx line. RAM guide.

FTB Skies 2 server requirements

Java	Java 21
Loader	NeoForge for Minecraft 1.21.1
CPU	Fast single-core speed (one main thread). With 406 mods, the first start takes minutes.
RAM	About 9–15 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 FTB Skies 2

Heavy

12 GB RAM · planned launch price $42/month

With 406 server-side mods and FTB recommending 8 GB for the game alone, 12 GB gives the server room for its players' chunks too.

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 Heavy servers open.

Join the launch list Compare all plans

Heavy is our biggest plan. 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 an FTB Skies 2 server on your own PC

What's specific to FTB Skies 2, step by step. The full walkthrough for any pack: how to make a modded Minecraft server.

Install Java 21.
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 the run.sh / run.bat the NeoForge 1.21.1 installer writes, then set eula=true in eula.txt if you accept Mojang's EULA (EULA step). With 406 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 FTB Skies 2 on DSN

Once we relaunch (join the launch list), on DSN you'd install FTB Skies 2 from the panel's CurseForge modpack installer, pick Java 21 on the Startup tab and accept the EULA in the console. No port forwarding.

How to play FTB Skies 2 with friends

Each player installs FTB Skies 2 with the FTB App, the same version as the server, and adds the server's address under Multiplayer. The authors' memory advice for the game: FTB's launcher setting for this pack is 8 GB recommended and 6 GB minimum, for the game.

Different versions of FTB Skies 2 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 FTB Skies 2

Can't keep up! Is the server overloaded? means ticks take longer than 50 ms; more RAM won't fix that once FTB Skies 2 has enough (tick lag guide). For FTB Skies 2:

Measure first: spark's /spark tps and profiler work on 1.21.1 and name the mod or machine using the tick time.
Distances: view-distance=8 and a lower simulation-distance in server.properties.
Pre-generate: Chunky for 1.21.1, /chunky radius 3000 then /chunky start, before people explore.
Chunk loaders keep machines running with nobody nearby; in a pack this size, dozens add up.

Common FTB Skies 2 crashes

What a NeoForge 1.21.1 server running FTB Skies 2 hits most. For any other error, paste the log into the free crash log analyzer.

Out of memory. FTB Skies 2 (406 mods) needs about 9–10 GB for 1–3 players; java.lang.OutOfMemoryError means it ran out. Out-of-memory fix.
Wrong Java version. FTB Skies 2 on Minecraft 1.21.1 needs Java 21. Started on Java 17, it stops with UnsupportedClassVersionError: ... class file version 65.0, this version of the Java Runtime only recognizes class file versions up to 61.0. Java version fix.
Client-only mod on the server. FTB Skies 2 includes 30 client-only mods, which a server install skips; copying a player's mods folder brings them back and stops the 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 FTB Skies 2 by hand usually crash it with a missing dependency or a mixin conflict.
Ticking entity or block entity. The crash report names it and gives its coordinates. Ticking entity fix.

Updates and support

Before moving FTB Skies 2 past version 1.23.0, back up the world: see updating a modpack server without losing your world.

Bugs in FTB Skies 2 itself go to its authors: issue tracker and wiki. Server problems on DSN: hello@dsnservers.com or Discord.

More: NeoForge server hosting, all modpack guides and how to make a modded server.

Run FTB Skies 2 on DSN when we relaunch.

Our pick, Heavy: 12 GB, planned at $42/month.

Join the launch list

DSN Servers isn't affiliated with FTB Skies 2 or FTB. We wrote the summary and checked the pack's facts by hand on October 4, 2026. Sources: feed-the-beast.com, api.feed-the-beast.com, curseforge.com, api.cfwidget.com.