IP Security Suite

IP Security Suite is a server-side mod that protects accounts, operator accounts in particular, from being taken over from another network. Once a player logs in, the mod remembers the IP address the player connected from. A lock can then be set so that later logins from other locations are refused, which the author describes as a defence against hacking and against IP bans being evaded through VPNs. Administration runs through the ipss command and its subcommands, typed in the server terminal or by an operator in game.

The mod can also block users who connect through a VPN or proxy. That check depends on an API key from a free VPN-detection service, so the server owner must create an account with that service, copy the key into the configuration and set the VPN option to true. Without the key, the VPN check does nothing even when the option is enabled. The author adds that an operator's IP address can be revealed to other players on some servers, which is why operator locks are recommended.

Strict mode goes further: once it is enabled, a player who is not registered cannot log in at all, so the server behaves like a whitelist. Self-lock can be turned off so that only operators are locked and regular players stay free to join from anywhere. Installation is limited to the server. Players join without installing anything, and the mod is published for Fabric on 1.21 – 1.21.3, with 1.3.1+1.21.1 for 1.21.1 as the latest file. It is open source under the GNU General Public License v3.0 only.