To run a stable 3.3.5a server, you must extract and provide four primary types of data to the server core. 🏛️ DBC (Data Base Client)
These contain the "rules" of the game world—spell data, item stats, talent trees, and NPC definitions. The server reads these to ensure mechanics (like a Mage's Blink or a Paladin's Aura) work exactly as they did in the retail 3.3.5a patch.