DNS propagation
The common name for the delay before a DNS change is seen everywhere, caused by resolvers caching old answers until their TTLs expire.
What it means
DNS changes are not pushed out. Your DNS host serves the new record at once; resolvers holding the old answer, or a cached "does not exist", keep it until its TTL runs out. Different resolvers cached at different times, so the change appears gradually. Nameserver changes take longest, because resolvers also cache the parent zone's delegation, whose TTL the registry sets.
Providers quote generous windows to cover this: Google says SPF can take up to 48 hours to start working. Most changes are visible far sooner, depending on the old TTL.
To check, query the authoritative nameserver directly: if it returns the new value, the change is live and the rest is caching.
Related terms
On this site
Sources
What this definition rests on. The wording is ours; the facts are theirs.
- Cloudflare docs: Time to Live (TTL)developers.cloudflare.com
- RFC 1034: Domain Names: Concepts and Facilities, section 4.3.4rfc-editor.org
- Google Workspace Admin Help: Set up SPFknowledge.workspace.google.com
All 432 terms in the glossaryThe wiki: blocklists and bounce codes