When you change a DNS record or update your domain's nameservers, the change doesn't reach every device on the internet instantly. It spreads gradually as different networks and internet service providers refresh their cached copy of your domain's information, a process known as propagation.
Why Propagation Isn't Instant
DNS relies on caching to work quickly at a global scale. Rather than every device looking up your domain's records fresh each time, ISPs and DNS resolvers store a copy for a set period, defined by a value called TTL (time to live), before checking again. Until that stored copy expires, some visitors will keep seeing the old records even after you've changed them.
Typical Propagation Times
- DNS record changes (A records, MX records, and similar) usually complete within a few hours, though some resolvers may take up to 24 hours depending on their cache settings.
- Nameserver changes tend to take longer, commonly 24-48 hours, since they involve updates at the registry level in addition to individual DNS caches.
In Kenya, propagation speed can also vary between mobile network operators and fixed-line ISPs, since each caches DNS independently. It's normal for a change to appear on one network before another.
During propagation, your site or email may work correctly for some visitors and not others, or may briefly point to both the old and new location depending on which server a request happens to reach. This is expected and resolves on its own.
Checking Propagation Status
You can check how far a DNS or nameserver change has spread using any public DNS lookup tool, which queries multiple locations worldwide and shows what each currently returns for your domain. If most locations show the new records but a few are still lagging, simply wait; there's nothing to fix on your end at that point.
Reducing Wait Time for Future Changes
If you're planning a change in advance, such as an upcoming host migration, you can lower your DNS records' TTL value a day or two beforehand. A shorter TTL means resolvers refresh their cache more often, so once you make the real change, it propagates faster.