When you change a DNS record, it does not slowly travel around the world.
Your authoritative nameserver usually serves the new value immediately.
The delay happens because DNS resolvers may still have the old value cached until its TTL expires.
That is why one person sees the new server while someone else still reaches the old one. For a clean migration:
- Lower the TTL before the change
- Wait for the previous TTL to expire
- Update the record
- Keep the old server online during the transition
“DNS propagation” is mostly a convenient name for thousands of independent caches expiring at different times.
Source: r/hosting_area · by /u/ench-hosting