Telnet UDP Port
Unfortunately telnet will only allow to test ports for TCP.
On the contrary nc can test ports for both TCP and UDP.
TCP
- # nc -z -v -u [hostname/IP address] [port number]
- # nc -z -v 192.168.10.12 22
- Connection to 192.118.20.95 22 port [tcp/ssh] succeeded!
UDP
- # nc -z -v [hostname/IP address] [port number]
- # nc -z -v -u 192.168.10.12 123
- Connection to 192.118.20.95 123 port [udp/ntp] succeeded!
Source : https://www.quora.com/Can-we-Telnet-UDP-port