CloseTheDoor is described as 'Indentifies all the listening ports TCP/UDP over IPv4/v6 and the associated program files. This will help you to detect security holes and close backdoors when you want to prevent remote attacks' and is an app in the network & admin category. There are five alternatives to CloseTheDoor for a variety of platforms, including Windows, Linux, Self-Hosted, Synology C2 and Unraid apps. The best CloseTheDoor alternative is CurrPorts, which is free. Other great apps like CloseTheDoor are Advanced Port Scanner, Free Port Scanner, portracker and Netactview.