Interview Questions/Phone Screen/DNS Propagation Basics
BeginnerPhone
2 min

DNS Propagation Basics

DNSNetworkingWeb
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Interview Question

What is DNS propagation, and why can DNS record changes take time to be visible globally?

Key Points to Cover
  • DNS caches across ISPs, resolvers, and browsers cause delay
  • TTL determines cache expiry duration
  • Propagation typically takes seconds to 48 hours globally
Evaluation Rubric
Mentions caching layers involved40% weight
Explains TTL impact30% weight
Provides typical propagation range30% weight
Hints
  • 💡Lower TTL before planned migrations to speed up.
Potential Follow-up Questions
  • How to force DNS refresh locally?
  • How do CDNs affect propagation?
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