swrpgservauth
by ShortWlf
swrpgservauth restricts server access to a predefined username allowlist, disconnecting any player whose name is not listed in the server's configuration file.
What it does
On a Fabric server, the mod checks each joining username against allowed players.json. A player who is not on the list is disconnected during login, so the server admits only the names its administrators have chosen. Administrators manage the allowlist through commands, and every change is written to the configuration file.
Optional IP verification adds a second check. A user can be bound to one or more registered IP addresses, and when verification is enabled the connecting address must match one of them. Verification is set globally by default and can be switched per user, so some accounts can be pinned to an address while others are not. Connection attempts are logged, and the server operator is informed when an unauthorized player tries to join.
It runs on the server alone, so players need nothing extra to join. It is published for Fabric and the single game version 1.21.5, with the 1.0.1 build dated 2025-05-19 as the latest file. The code is open source under the MIT License.
Key features
Username allowlist
Only names listed in allowed players.json can stay connected; any other player is removed during login.
User management commands
The addUser command adds a player to the allowed list, and each entry takes the global verifyIp setting by default.
IP registration
The addIp command attaches an IP address to an existing user, and that address must match when verification is enabled.
Per-user IP verification
The toggleUserIp command switches the verifyIp flag for one user, so IP checks apply to some accounts and not others.
Live configuration reload
The refreshConfig command reloads the JSON file, applying edits made outside the game without a restart.
Connection logging
Attempts by unlisted players are logged, and administrators are notified of them.
Gallery
Compatibility
Latest build for each game version and loader.
Only full game releases are shown. This mod publishes no snapshot builds.
How it compares
senthryX is a Fabric mod for 1.21.1 – 1.21.4 with the same server-side environment, under the MIT License, but it is not open source. IP Whitelist (Fabric) runs server-side and is open source under the GNU General Public License v3.0 only, with builds for 1.21.10 – 1.21.11, so it targets later versions than swrpgservauth. Modsender needs the client, while the server may skip it, and it is also not open source.
| Mod | Loaders | Game versions | Environment | Updated |
|---|---|---|---|---|
| swrpgservauth | Fabric | 1.21.5 | Server-side only | 2025-05-19 |
| senthryX | Fabric | 1.21.1 – 1.21.4 | Server-side only | 2025-06-07 |
| IP Whitelist (Fabric) | Fabric | 1.21.10 – 1.21.11 | Server-side only | 2026-01-29 |
| Modsender | Fabric | 1.21 – 1.21.11 | Client required, server optional | 2026-06-18 |
Questions
Does a player need swrpgservauth to join the server?
How are players added to the allowlist?
What does IP verification do?
In the catalog
swrpgservauth is one of 3,545 Optimization mods on ModsFinder, and one of 2,575 Optimization mods for Fabric. 15,307 mods support Minecraft 1.21.5.
More from ShortWlf
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What the author says
Swrpgservauth is a Minecraft server authentication mod that restricts player access based on a predefined username allowlist. The mod prevents unauthorized players from joining by checking their username against a configuration file (allowed_players.json). If a player is not listed, they are disconnected upon…
Official listing
- Modrinth page
- modrinth.com/mod/swrpgservauth
- Owner
- ShortWlf
- Published
- 2025-05-07
- Updated on Modrinth
- 2025-05-19
- Facts verified
- 2026-10-15