What is DNS propagation, and why can DNS record changes take time to be visible globally?
- DNS caches across ISPs, resolvers, and browsers cause delay
- TTL determines cache expiry duration
- Propagation typically takes seconds to 48 hours globally
- 💡Lower TTL before planned migrations to speed up.
- ⚠️Failing to explain the role of distributed caching at various levels (browser, OS, ISP resolvers).
- ⚠️Incorrectly defining or ignoring the significance of 'Time To Live' (TTL) and how it dictates cache expiry.
- ⚠️Stating a fixed or unrealistic propagation time instead of acknowledging the range (seconds to 48 hours).
- ⚠️Confusing the instant update at the authoritative DNS server with the global propagation across the internet.
- ⚠️Not explaining *why* caching is employed in DNS (i.e., for performance and efficiency benefits).
- ❓How to force DNS refresh locally?
- ❓How do CDNs affect propagation?
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