REF: AI Tools/OpenAI/ChatGPT
How many secondary DNS servers you can have against one primary DNS server
Technically, there is no strict limit to how many secondary (slave) DNS servers you can have for a single primary (master) DNS server. It depends on:
1. DNS Protocol Limits
- The DNS protocol itself does not impose a fixed number of secondary servers.
- You can have as many as you need, as long as your primary can handle the zone transfers (AXFR/IXFR) and your network resources allow.
2. Practical Considerations
- Zone Transfer Load: Every secondary server requests a copy of the zone from the primary. Too many secondaries can overload the primary.
- Network Latency & Bandwidth: If the primary is slow or far from some secondaries, propagation may be delayed.
- Management Complexity: More secondaries mean more monitoring and maintenance.
3. Typical Setup
- Most domains use 2–4 secondary servers for redundancy.
- Large organizations or TLDs may have dozens or even hundreds worldwide (often using anycast for global distribution).
✅ Summary:
- No hard limit per DNS standards.
- Practical limit depends on load, network, and management.
- Common practice: 2–4 secondaries for small to medium domains; many more for large/global services.
If you want, I can make a diagram showing a primary DNS server with multiple secondaries and how zone transfers work, which is very blog-friendly. Do you want me to do that?
