No Connect
by zomabies
No Connect is a Forge and NeoForge utility that restricts which remote hosts Minecraft can reach, blocking most outside connections by default.
What it does
The mod limits network connections from the game to remote addresses. Most outside connections are prevented, including ones used for updates, joining servers and similar traffic, while localhost resources and a default list of allowed hosts remain reachable. The list of allowed hosts is part of the mod's configuration.
It works through a ModLauncher transformation service plugin. That plugin depends on java.lang.SecurityManager, which is terminally deprecated under JEP 411 and needs Java 17 or later. On Java 18 and above the game must be started with the -Djava.security.manager=allow command-line option. The author notes that the mod was tested with Minecraft Forge 1.14.x and NeoForge 1.21.1, and that a Java 24 plugin version is in progress.
No Connect can be installed on a client, a server, or both, since either side can run it alone. Its files are published for Forge and NeoForge across 32 release versions, 1.14.4 – 1.21.4, and the code is released under the Open Software License 3.0 with source code available.
Key features
Remote connection blocking
Most outbound connections from the game are prevented, covering update checks and server joins.
Localhost and default hosts
Localhost resources and a built-in list of default hosts stay allowed while other remote addresses are blocked.
Configurable allowed hosts
The set of hosts that remain reachable can be adjusted through the mod's configuration.
Mod menu entry
The mod appears in the mod menu so its status can be checked from inside the game.
Compatibility
Latest build for each game version and loader.
1.21.x5 of 5 versions with builds
1.20.x7 of 7 versions with builds
1.19.x5 of 5 versions with builds
1.18.x3 of 3 versions with builds
1.17.x2 of 2 versions with builds
1.16.x6 of 6 versions with builds
1.15.x3 of 3 versions with builds
1.14.x1 of 1 version with builds
Only full game releases are shown. This mod publishes no snapshot builds.
Use cases
Offline play
Players who want the game to stay off the network can block remote connections while still using local resources.
Controlled environments
Server owners and testers can limit where a game instance is allowed to reach outside its own network.
Who it’s for: Players and server owners who want to restrict the game's remote network access, and who can supply the command-line option that newer Java versions need.
Questions
Does No Connect need the Java command-line option?
Does No Connect have to be installed on the server?
Which loaders does No Connect support?
Is the source code of No Connect available?
In the catalog
No Connect is one of 7,555 Cursed mods on ModsFinder, and one of 3,426 Cursed mods for Forge. 17,979 mods support Minecraft 1.21.4.
More from zomabies
Similar mods
What the author says
Prevent connections to remote * (mostly) but not limited to, such as update, joining server, etc. *Except localhost resources and default allowed hosts. Credit to contributors of for references.
Official listing
- Modrinth page
- modrinth.com/mod/no-connect
- Owner
- zomabies
- Published
- 2023-12-25
- Updated on Modrinth
- 2025-01-01
- Facts verified
- 2026-10-15