Services discovery? Chaos?

[xuftugulus]

A simple question which actually has sent me through tons of information and i am confused.

Question: When a server is running on a specific port, is there a standard way to announce the provided service to someone connecting on the port?

I couldn't make anything from Google'ing, or at least didn't understand where to look...

[xuftugulus]

I will reply to myself that there is no standard as much as i searched. The traditional way used by nmap is to parse the server response for discovering a standard service. A non-standard service has no way to announce it's type or purpose, other than the author of the service provide a list of the services available commands in a long and boring, but definately forcingly complete way.

[CornedBee]

No. A program could sniff for the provided service by listening and trying out a few commands, but there's really no method of identifying a service.