According to the Server Fault 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 and virtualization
- 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.