NefAuth
by Prime_21k
NefAuth is a NeoForge authentication mod for servers that lets players register and log in with passwords before they can play.
What it does
Before a player logs in, the mod blocks movement, chat and commands, so an unauthenticated account cannot act on the server. Passwords are stored with secure hashing algorithms rather than as plain text, and the account records are kept in the usernamecache.json file. Session management keeps a logged-in player signed in until the session ends.
The mod is built specifically for NeoForge 1.21.1 and is not a hybrid server build, so it does not need Arclight, Mohist or a similar jar. It is meant for servers running offline mode (online-mode=false), where authentication prevents unauthorized access and account theft. It is a server-side only mod: players join without installing anything, and the server only needs the mods directory.
Key features
Password hashing
Passwords are hashed with secure algorithms instead of being kept in plain text.
Login gate
Players cannot move, chat or run commands until they have logged in or registered.
Session management
A player who has logged in stays signed in for the session, so re-authentication is not required each time.
Register and login commands
Players create an account and sign in with dedicated commands, which the server handles directly.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Offline-mode servers
Servers running with online-mode=false use it to stop unauthorized players from taking over accounts.
Large modpacks
Modpack servers, such as ATM-style packs, can add authentication without changing the rest of the mod list.
Who it’s for: Server owners running NeoForge 1.21.1 who need player accounts, especially on offline-mode servers and large modpacks. Players need no installation.
How it compares
NullPass is server-side only, released under the MIT License and published for NeoForge 1.21.1. Basic Login is also server-side only and MIT licensed, but its files cover 1.21 – 1.21.4. MixAuth is server-side only and open source under the GNU Lesser General Public License v3.0 only, with files for NeoForge across 1.21.1 – 26.3, a wider range than NefAuth's single version.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| NefAuth | NeoForge | 1.21.1 | Server-side only | 2026-08-06 |
| NullPass | NeoForge | 1.21.1 | Server-side only | 2026-08-10 |
| Basic Login | NeoForge | 1.21 – 1.21.4 | Server-side only | 2025-01-15 |
| MixAuth | NeoForge | 1.21.1 – 26.3 | Server-side only | 2026-09-28 |
Questions
Does NefAuth need to be installed on the client?
Can NefAuth run on Arclight or Mohist?
Where does the mod keep account credentials?
In the catalog
NefAuth is one of 8,016 Management mods on ModsFinder, and one of 2,689 Management mods for NeoForge. 32,366 mods support Minecraft 1.21.1.
Similar mods
What the author says
A lightweight, secure, and server-only authentication mod designed for NeoForge 1.21.1. Perfect for large modpacks like All the Mods (ATM) running in offline mode (online-mode=false) to prevent unauthorized access and account theft.
Official listing
- Modrinth page
- modrinth.com/mod/nefauth
- Owner
- Prime_21k
- Published
- 2026-08-05
- Updated on Modrinth
- 2026-08-06
- Facts verified
- 2026-10-15