Acoording to the Serverfault FAQ:
Frequently Asked Questions
What kind of questions can I ask here?
Server Fault is for Information Technology Professionals needing expert answers related to managing computer systems in a professional capacity.
If your question is about…
Server and Business Workstation operating systems, hardware, software
Enterprise storage, backup, and disaster recovery
Network routing, switches, and firewalls
Operations, maintenance, and monitoring
DNS should fall in the Network routing category.
Besides, dns is a tag with 4k entries.