We often walk into an environment where either a previous network administrator or current IT staff implement nonstandard ports for FTP, RDP, IIS port bindings, or other protocols on Windows Servers. While we do agree with the saying “security by obscurity is no security at all,” we like the practice of using nonstandard port ranges for services that are common targets.
While the practice turns away the low-lying fruit of the hacking/port scanning public and provides the opportunity for port translation from an edge firewall, it does make the situation a bit more complicated for an unfamiliar server administrator.
Here is a command to show all listening TCP and UDP ports on a Windows server.
netstat -an | find /i "listening"