benhosmer

Using the nc command you can scan a port or a range of ports to verify whether a UDP port is open and able to receive traffic.

This first command will scan all of the UDP ports from 1 to 65535 and add the results to a text file:

$ nc -vnzu server.ip.address.here 1-65535 > udp-scan-results.txt

This merely tells you that the UDP ports are open and receive traffic.

Perhaps a more revealing test would be to actually transfer a file using UDP.