Alternative tools to nmap exist. One common tool is masscan. Masscan is designed to be a fast network scanner. A key difference between masscan and nmap is that there must be either an individual, or list of ports explicitly chosen for a masscan scan. By default masscan scans TCP so to test UDP ports the -pU flag must be used.

The syntax to run masscan against UDP ports is:

Masscan -pU # <IP address>

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