DNS changes do not take effect everywhere at once. After you add, edit or remove a DNS record — or change the nameservers for a domain — resolvers across the internet keep serving the previous answer until their cached copy expires.
How long it takes
- Most changes become visible within a few hours.
- Full propagation usually takes 2 to 48 hours.
- In rare cases up to 72 hours.
The actual time depends on the record's TTL, the registrar, the DNS providers involved and the caching behaviour of individual internet providers. Nameserver changes at the registrar generally take longer than editing a record within an existing zone.
Plan ahead with TTL
The TTL of a record is how long resolvers are told to keep the answer. If you know in advance that you will be changing a record — moving a site to another server, for example — lower its TTL to a few minutes a day or two beforehand. When the change is made, it then spreads almost immediately. Afterwards, raise the TTL again.
This is the single most useful thing you can do to make a migration painless, and it has to be done before the change, not after.
Checking whether the change has taken effect
Do not rely on opening the site in your own browser: your operating system and browser cache DNS answers as well, so you may be looking at a stale result long after the change has spread.
Query DNS directly instead:
dig example.com nslookup example.com
To see what a public resolver returns rather than your provider's:
dig @1.1.1.1 example.com
Online tools that check a domain from several locations at once are also useful for seeing how far the change has spread.
What to expect meanwhile
During propagation, some visitors reach the new server and others still reach the old one. This is normal and does not mean the record is wrong. Two practical consequences:
- Keep the old server running until propagation is complete. Switching it off immediately means visitors still holding the old address see nothing at all.
- Be careful with sites that write data. A shop or forum reachable at both servers can accumulate orders or posts on the old one, which then have to be reconciled. If that matters, put the old site into a read-only or maintenance state when you make the change.
Before contacting support
Give the change time, and check the record with dig against a public resolver first. If the record is correct there but the site or mail still does not work after 48 hours, open a ticket from your client area with the domain name and what you changed.
Resist the temptation to keep editing records while waiting. Each change starts its own propagation period, and a series of edits made in quick succession is much harder to diagnose than a single one.
