Portscan is an open source and free TCP port scanner based on Perl, capable of conducting a full handshake. It's recommended to use it only to scan your own devices as scanning foreign hosts can be viewed as offensive.
One of the main benefits of portscan is that it does a full handshake. This means that it establishes a connection with the target port before scanning it. As a result, it gives more accurate results and minimizes the risk of false positives.
However, it's important to note that using portscan to scan foreign hosts is not recommended since it can be seen as offensive. Instead, it's best to use it to check your own machines to ensure they are secure.
Overall, portscan is a great option for network administrators or anyone looking to secure their own systems. With its reliable scanning capabilities and easy-to-understand code, it's definitely worth giving a try.