Set up the FTB Inferno modpack server

FTB Inferno is an expert-style questing and survival pack from the Feed The Beast team, built on Minecraft 1.18.2 with Forge. Its page describes a fire and blood theme with custom dungeons, an invasion system and five major bosses. You install the server from the Modpacks tab, using the Feed The Beast source or the CurseForge source.

Checked against FTB Inferno 1.12.0 (released in May 2026) on Forge 40.2.34 and Minecraft 1.18.2, October 2026.

What the pack needs

• Minecraft 1.18.2 with Forge 40.2.34 and Java 17. These are the targets Feed The Beast lists for 1.12.0. The panel runs 1.18.2 on Java 17 and picks it for you.
• Memory. Feed The Beast lists 4096 MB as the minimum and 6144 MB as the recommended amount for this version. Your plan sets the RAM, so read how much RAM a Minecraft server needs and check the Minecraft plans before you install.
• The same pack version for players. Players need the same version your server installs. This guide was checked against 1.12.0, and players run it from the FTB App, Feed The Beast's own launcher.

Install from Feed The Beast

1. Open your server and choose Modpacks under Content in the left rail.
2. In the search card, press the Feed The Beast button in the row of sources and search for FTB Inferno.
3. Press Install. The popup reads "This reinstalls your server with FTB Inferno (Forge, Minecraft 1.18.2)." The version menu shows Newest that fits your server, which installed 1.12.0 when this guide was checked. This source lists no mods to download by hand.
4. Leave Take a backup first ticked. Your current world is replaced by the pack's.
5. Hold Install and reinstall until it fills, then wait for the install to finish. It took about a minute and a half when this guide was checked.

Install from CurseForge instead

CurseForge's FTB Inferno file has no dedicated server pack. It is the client file, a list of the pack's mods plus its configs, and the panel reads that list and downloads each mod. Modpack mods to download from CurseForge explains the drop-in step.

1. Open your server and choose Modpacks under Content in the left rail.
2. In the search card, press the CurseForge button in the row of sources and search for FTB Inferno.
3. Press Install. With the updated installer on, the popup names mods CurseForge does not hand out for download. Otherwise the Modpacks tab lists them after the install. When this guide was checked there were two, Hexerei and Overloaded Armor Bar (Updated).
4. Download Hexerei from its CurseForge page and drop it into the popup, or into the list on the Modpacks tab if it shows there after the install. It is a content mod, so add it before players join. Overloaded Armor Bar (Updated) only changes how the armour bar is drawn. The install button stays locked until you have dropped both files or ticked Install without them (add them later from this tab).
5. Leave Take a backup first ticked. Your current world is replaced by the pack's.
6. Hold Install and reinstall until it fills, then wait for the install to finish. The panel downloads the pack's 264 mods one by one, and the install took about three to four minutes when this guide was checked.

First start

Press Start on the Console tab and accept the EULA if the panel asks. The server is up when the console prints a line containing For help, type. On an 8 GB plan the CurseForge install's first start took about two minutes when this guide was checked, and the server started without Hexerei and Overloaded Armor Bar (Updated). Your address is in the left rail with a copy button beside it. The Server address label shows on wide screens only. Connect to your server for the first time covers adding it in Minecraft.

Common problems

• A player cannot join. Check they run the same FTB Inferno version as the server.
• The install does not start. If the message says Couldn't start a backup, free a backup slot, or untick Take a backup first and try again.
• The install fails. Read the last lines of the installer output that the Console tab prints under Install failed.
• The first start stops on a Carry On crash. When this guide was checked, the Feed The Beast install's first start printed Configuration file ./world/serverconfig/carryon-server.toml is not correct. Correcting, then crashed with ArrayIndexOutOfBoundsException in Carry On's ListHandler, and the server stayed on Starting. Press Force stop, hold Force stop in the popup to confirm, then press Start again. The second start reached Done.
• The server lags or runs out of memory. Watch the RAM card on the Console tab and the TPS reading in the left rail. Why is my server lagging has more.
• The server crashes at boot. Find and read a crash report shows how to name the mod at fault.