To reopen this in future just delete the two rules Do this twice for both TCP and UDP and they will not be able to connect to multiplayer. Hit Next twice and then give the rule a name (minecraft Multiplayer) and click finish. You will need to do this for both TCP & UDP and then click Specific Local Ports and change the value to 25565 (this is the default port for minecraft servers so will cover the majority of servers You will then see the following menu, Select Port as the option and click Next Go to Control Panel - System and Security - windows firewall, then click advanced settings.