nc -v

nc -v 10.11.3.236 5432
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connected to 10.11.3.236:5432.

nc -v 10.11.3.236 5433
Ncat: Version 7.50 ( https://nmap.org/ncat )
Ncat: Connection timed out.

• nping

See also

• telnet, netcat, nc, nc -l, ncat, socat, ngrok