DNP3 20000 (TCP-UDP)

Industrial communication protocol for remote monitoring and control of automation systems

Shodan:product:"DNP3"

censys (better) (((services.port:"20000") and labels=`scada`) and services.service_name=`DNP3`) 

Nmap:

sudo nmap --script=dnp3-info -p 20000 -sV 179.133.95.177