It's easy for you to recognize trolling, the nest reputation part of the trolling.
But you need to understand "troll" usually we mention slang, even though it's a slang but someone who does a lay and silly troll.

In short, if you see someone posting or making a topic and deliberately uploading comments that are always indentic with provocative or offending other members or generally can interfere in online forums and what they aim to create emotional reactions, provoke conflict towards others, that's the trolling.

In general, trolling behavior is diverse and aggressive such as toxic behavior, provocative, insulting, inciting and so on, that is the general nature of trolling.