The Global DNS System
DNS (Domain Name System) is a globally distributed database. There is no single server that every computer on Earth queries. Instead, there are thousands of DNS resolvers around the world, each caching the answers they have already looked up.
When you change a DNS record, you update the authoritative nameserver for your domain. But every cached copy of the old record on every resolver around the world has to expire before they will pick up the new one.
This process is called DNS propagation.
How Long Does It Take?
Propagation time depends on the TTL (Time to Live) value of the record you changed. TTL is measured in seconds and tells resolvers how long to cache the record before checking again.
- A TTL of 14400 means records are cached for 4 hours
- A TTL of 300 means records are cached for 5 minutes
- A TTL of 86400 means records are cached for 24 hours
The JIJ default TTL is 14400. For most DNS changes, expect full global propagation within 4 hours, though it can take up to 48 hours in edge cases.
How to Speed Up Propagation
Before making a planned DNS change, lower the TTL to 300 seconds (5 minutes) 24 hours in advance. This means the old cached records expire quickly after you make the change. After the new records have propagated, raise the TTL back to 14400.
Checking Propagation
Use dnschecker.org to see what different resolvers around the world are returning for your domain. When most show your new record, propagation is complete.