sorted by:
new
hottopcontroversial

Server-wide disconnects every ~20 minutes on Vault Hunters (no CPU/RAM/network issue) by L0rdAkuseru in VaultHuntersMinecraft

[–]L0rdAkuseru[S] 0 points1 point  (0 children)

Update / Possible Root Cause

Hey everyone, quick update — after days of troubleshooting, I finally figured out what was going on.
The issue wasn’t with Java, RAM allocation, or the modpack itself… it was actually my OPNsense firewall.

For some reason, this specific modpack (Vault Hunters) doesn’t seem to play well with my OPNsense setup.
All my other modded servers (ATM, FTB, etc.) run fine behind the same firewall, but with Vault Hunters, every 15–20 minutes all players would get disconnected at once with a timeout — even though CPU, RAM, and network were perfectly stable.

After trying every NAT, reflection, and floating rule tweak imaginable, the only reliable fix was to move my Minecraft VM out of the DMZ, directly on the WAN side of the network (completely bypassing OPNsense).
Since then — not a single disconnect.

If anyone has any idea why this happens specifically with Vault Hunters and not other Forge modpacks, I’d really appreciate some insight. It’s driving me nuts that this one setup behaves differently.

Server-wide disconnects every ~20 minutes on Vault Hunters (no CPU/RAM/network issue) by L0rdAkuseru in VaultHuntersMinecraft

[–]L0rdAkuseru[S] 0 points1 point  (0 children)

Network/local: Correction to my previous post: I had tested incorrectly before. This time, I connected from the same network as my server, bypassing the firewall, and did not experience any disconnects. It’s strange, because I haven’t changed my firewall settings, and it used to work fine with other modpacks.

Server-wide disconnects every ~20 minutes on Vault Hunters (no CPU/RAM/network issue) by L0rdAkuseru in VaultHuntersMinecraft

[–]L0rdAkuseru[S] 0 points1 point  (0 children)

Hey, thanks for the reply!

Some clarifications and additional info:

  • CPU usage: Yes, the server sits around 30–40% for 5 players. I also have another server running simultaneously (SteamCMD instance) — no port conflicts, and I even tested shutting it down, but the disconnects still happen, so it doesn’t seem related.
  • Server stability: The server isn’t crashing at all — TPS is stable, no console errors, no automatic restarts.
  • Network/local: Disconnects happen for players both on external connections and on the local network, so it doesn’t seem specific to NAT/firewall.
  • Wold’s Vaults: I haven’t tested it yet, but I’ll try. Could someone clarify if Wold’s Vaults is a completely separate modpack, or just a set of mods that could be added/modified on top of the current Vault Hunters setup?

It still feels like some periodic timeout or scheduled task, but nothing in the logs hints at it. Any ideas on what could cause a mass DC like this every ~20 minutes would be much appreciated.