Changing Nameservers: How Long DNS Propagation Really Takes
After a nameserver change, some visitors see the new site and some the old one for a while. That is DNS caching, and it follows clear rules. Here is how long it takes, why, and how to move a domain without breaking your site or email.
Key points
- "Propagation" is really caches expiring: every DNS answer carries a TTL that says how long it may be kept.
- A change to a record inside your zone takes as long as that record's TTL — often minutes to an hour.
- A nameserver change can take up to about 48 hours, because the old nameservers are cached for up to two days.
- Copy every record, email ones included, to the new DNS host before you switch, and turn off DNSSEC first if it is on.
- Check the move with a DNS propagation checker and a WHOIS lookup rather than your own browser.
A change to a DNS record usually reaches everybody within the record's TTL — often minutes to an hour. A change of nameservers can take up to about 48 hours, because the old nameservers may be cached for up to two days. "DNS propagation" is not a change spreading out; it is old answers being forgotten, cache by cache.
What nameservers and DNS records are
The Domain Name System (DNS) turns names like yourshop.com into the addresses computers use. Two layers are involved:
- Nameservers are set at the registrar where you bought the domain. They say which DNS host answers for the domain — for example, your hosting company's.
- DNS records live at that DNS host, in your domain's zone. They hold the actual answers: the
Arecord (the web server's IPv4 address),AAAA(IPv6),MX(where email goes),TXT(SPF, DKIM and DMARC for email, and verification codes),CNAME(an alias for another name).
Changing nameservers moves the whole zone to a different DNS host. Changing a record changes one answer within the zone you already use.
Why it takes time: TTL and caching
Nobody asks your DNS host directly every time. Internet providers, companies and public services such as Google's and Cloudflare's run resolvers that look a name up once and remember the answer for as long as its TTL (time to live, in seconds) allows. Your computer and your browser keep their own short-lived copies too.
- Changing a record: resolvers that already hold the old answer keep using it until its TTL runs out. A TTL of 3600 means up to an hour; 300 means up to five minutes.
- Changing nameservers: the list of nameservers for a domain is published by the registry of its ending, with a TTL of its own. For .com and .net that TTL is 172,800 seconds — two days. A resolver that looked your domain up just before the change may keep asking the old nameservers for up to 48 hours. Most resolvers pick the new ones up much sooner, which is why a move often looks finished within a few hours.
How to move a domain without breaking anything
- List every record you have now. Look the domain up with a DNS lookup for each type — A, AAAA, MX, TXT, CNAME — and write the answers down. Email records are the ones most often forgotten.
- Create the same records at the new DNS host, changing only what should change (usually the A record, to point to the new server). If your new host manages your mail too, use the MX, SPF, DKIM and DMARC records it gives you.
- Turn off DNSSEC first, if it is on. If your registrar has a DS record for the domain and the new DNS host does not sign your zone with the matching keys, resolvers that check DNSSEC will refuse to answer for your domain at all. Remove the DS record, wait a day, and then switch.
- Change the nameservers at your registrar to the ones your new host gives you.
- Keep the old hosting running for at least two days, so visitors whose resolver still has the old answer see a working site, not an error. Do not post new content on the old copy in the meantime.
- Check the result from outside your own computer (below).
Lower the TTL before a planned change
If you only need to change a record — moving the site to a new server while keeping the same DNS host — lower that record's TTL to 300 a day before. When you then change it, resolvers forget the old answer within five minutes. Put the TTL back up once the move is done.
How to check whether the change has reached everybody
- The DNS propagation checker asks several public resolvers at once and shows which already return the new answer and which still have the old one.
- A WHOIS lookup shows which nameservers the registry now has for the domain.
- The DNS lookup shows the records a resolver returns right now.
Your own browser is the worst place to judge from, because your computer and browser cache answers too. If the checker shows the new address everywhere but your computer does not, clear its DNS cache: on Windows run ipconfig /flushdns; on macOS run sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder. Or try the site on your phone over mobile data.
DNS at Hostular
When your domain uses our nameservers, every domain on your hosting account has its own zone, made automatically, and you manage its records yourself from your panel — including the email records, which the panel publishes for the domains that receive mail. Moving an existing site to us? Follow the steps above, and keep your old host until the checker shows the new address everywhere.
Next, make sure your email arrives: set up SPF, DKIM and DMARC.
Questions and answers
How long does DNS propagation take?
A changed record reaches everybody within its TTL, often minutes to an hour. A nameserver change can take up to about 48 hours, because the old nameservers for .com and .net may be cached for two days, though most resolvers pick up the change within a few hours.
Why does my site show the new version on my phone but the old one on my computer?
They use different resolvers, and your computer keeps its own DNS cache. The phone's resolver has already forgotten the old answer; your computer has not. Clear the computer's DNS cache, or wait until the old answer's TTL runs out.
Can I speed up DNS propagation?
Not after the change. Before a planned change, lower the record's TTL (for example to 300 seconds) a day in advance, so caches forget the old answer quickly. A nameserver change cannot be sped up, because its cache time is set by the domain's registry.
Will my email stop working when I change nameservers?
It will if the new DNS host does not have your MX and email TXT records. Copy every record, email ones included, to the new DNS host before you change the nameservers.
