Security firm Praetorian has open-sourced Nerva, a CLI tool that identifies what services are running on open network ports

What’s Running on That Port? Introducing Nerva for Service Fingerprinting

Introducing Nerva, a high-performance CLI tool that identifies 120+ protocols across TCP, UDP, and SCTP — 4x faster than nmap -sV. Built to bridge the gap between port discovery and service identification in security workflows.