[Question] NPC and Quest interaction

[Spira]

I am trying to understand how the server and client interact with quests and NPC's in general. For instance, where does the server send the NPC data of those in range of the player?

I am not sure how the client tells if it has a quest or not. Does the NPC data simply come with Yes/No it has a quest? Then the client just queries the server for the quests of a certain NPC? However I only see an opcode for the server to send the list (SMSG_QUESTGIVER_QUEST_LIST) no client opcode for requesting.

In any case I think there are a lot of ways it could be done, just not sure how it is done here. Can anyone give me a brief description on how the client and server do quests?

[VladimirMangos]

CMSG_QUESTGIVER_STATUS_MULTIPLE_QUERY and CMSG_QUESTGIVER_STATUS_QUERY used by client for ask npc state

[Spira]

Does this mean it sends a query every time they see an NPC, even if they've seen it before?

[VladimirMangos]

client known what object seen or not. So it send (as i expect not test) query for recently created at client side objects (so seen now)