We do use "Troll" and "trollen" in German forums. But is there another Word that predates the Internet that could be used instead?
According to the Wikipedia article, troll originates from the French verb trôler, but also from the Norse word troll.
Let's concentrate on the second one here. A troll is a mythological monster. The German word for Troll is Troll, so there is no difference.
As for the activity of trolling: This is an artificial word created for this purpose, so there is no direct translation we can use. However, trolling means something like ködern (as you can read here). So I would go for that.
While these words differ from each other in the exact behavior ascribed to the individual, each of them can be used for an Internet troll that does show the respective behavior, which by definition is at least that of the last listed one (Provokateur).
All of these words are derived from verbs or verbal expressions:
While these verbs can be used to describe aspects of the behavior of Internet trolls, in my opinion none of them are a sufficiently exact synonym of "to troll" (or the new (on DWDS yet undocumented) meaning of the German verb "trollen" derived from that), especially as the more generic ones stören and provozieren don't imply intention (Man kann versehentlich stören oder provozieren.) while Internet trolling is always an intentional behavior. Further, "stören" and "provozieren" in my understanding somewhat imply "success" at bothering or provoking others, while "to troll" / "trollen" can in my opinion also refer to a (potentially unsuccessful) attempt to do so.
1 The also listed "Unhold" can (in reference to the mythological creatures) refer to a non-mythological male person (in the meaning of "grober, ungeschlachter Kerl"; a brute, maybe cloddish man), but is not really applicable to Internet trolls.