For UDP?

[mathew-bulletin]

Enhancement request:

• Is there any chance to have UDP test added for this script?

[SrikanthTati]

Curious if this is even possible given that UDP is connectionless?

[garethrandall]

I believe you would get an ICMP Destination Unreachable packet for a UDP packet sent to a non-listening port, so you could tell if the port was not listening. However, this approach would have problems with firewalls since if the port were blocked by a firewall or docker config (and hence no ICMP Destination Unreachable) it would look like it were open.