DNS & Domains
Verify propagation
DNS changes take time to spread across the internet. DunOps can check whether your records have propagated and from where.
How propagation works
When you update a DNS record, the change starts at your registrar's nameservers. Other resolvers cache the old value until the TTL (Time To Live) expires — then they re-query and pick up the new value. A 3600-second TTL means full propagation can take up to an hour; a 60-second TTL means most resolvers update in under a minute.
Checking propagation from chat
Has my DNS change for app.example.com propagated?
Check if the A record for example.com is resolving to 76.76.21.21 yet
Is the CNAME for www.example.com pointing to my Vercel deployment?DunOps queries multiple public resolvers (8.8.8.8, 1.1.1.1, and your registrar's authoritative nameserver) and reports what each one sees. If they disagree, propagation is still in progress.
Note
Lowering TTL before a migration
Before a planned DNS cutover (e.g. moving a domain to a new provider), lower the TTL of the records you'll change to 60–300 seconds a day in advance. After the cutover, raise it back to 3600. This makes rollback nearly instant if something goes wrong.
Tip
Set the TTL for app.example.com to 60 seconds — it proposes the change and waits for your approval.