What is split-brain (or split-horizon) DNS?
Split-brain DNS (split-horizon) returns different answers based on who is asking:
- Internal queries: Users inside your network see internal IP addresses.
- External queries: Users on the internet see public IP addresses.
How it works:
- Internal DNS servers have one set of records
- External/public DNS has different records
- Query source determines which answer you get
Use cases:
- Internal servers accessible directly inside network
- Same hostnames resolve differently by location
- Can improve performance and security
Complexity: Requires maintaining two sets of records. Can cause confusion when troubleshooting.
Different docking instructions for local harbor traffic versus ships arriving from open sea.
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