I was running the programs netbeans, and a window pop up and by accident I clicked "Keep Blocking". How can I undo my mistake? Is there a setting in control panel, that I can undo my mistake? Thanks for any help!

You want to open Control Panel, Security, Windows Firewall and then down the left-hand side you will see 'Allow a program through Windows Firewall'. You need to click this and then a box will open with a list of programs. Tick the box next to the program you want to be allowed through, if it's not there just use the browse button.

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