Advanced PortChecker is a freeware utility that enables you to quickly find open TCP and UDP ports.

This little utility will provide data in real-time about a certain TCP/IP ports is open as it scans through the specified settings and can be set for a specific connection time-out. All compiled data can be exported to HTML, CSV and TXT formats. You also have the option to check for TCP only or both TCP and UDP. All data gathered is displayed from a simple GUI (that can be mildly customized) and it will also display the hostname if available.

Advanced PortChecker really is a foolproof option for port scanning that any skill level can utilize and the fact that it displays details in real-time will allow you to immediately engage an open port.