DNS propagation is the time it takes for a DNS record change to reach servers across the internet. Many people wonder: "I changed the setting but the site still shows the old server" β this is normal.
Why does it take time?
There are thousands of DNS servers (resolvers) on the internet. For speed they cache DNS records. When you change a record, these servers keep the old value until the TTL expires. Only then do they request the new one.
TTL β the main factor
TTL (Time To Live) sets how many seconds a record is cached. 3600 = 1 hour, 86400 = 1 day. The larger the TTL, the slower propagation. Planning a migration β lower the TTL to 300 (5 minutes) a week ahead.
How long?
1) Usually 1-4 hours. 2) Full global propagation up to 24-48 hours (rare). 3) NS (name server) changes are slowest β 24-72 hours. 4) A, CNAME records are faster.
Checking tools
1) whatsmydns.net β DNS status from various points worldwide. 2) dnschecker.org. 3) Terminal: dig sayt.uz or nslookup sayt.uz. 4) dig +trace sayt.uz β the full chain.
Local cache issue
Sometimes the change has propagated but your computer shows the old version. Fix:
- Windows: ipconfig /flushdns
- Mac: sudo dscacheutil -flushcache
- Clear browser cache or use incognito.
Migration strategy
1) Fully prepare the new server. 2) A week ahead, TTL β 300. 3) Change DNS (or NS). 4) Let old and new servers run in parallel for a while. 5) After propagation, shut down the old one.
NS vs A record
Changing only hosting β update the A record (IP), fast. Moving all DNS management β change NS, slower.
Sayt.uz practice
When you buy a domain through Sayt.uz, DNS points to our servers immediately. During migration the tech team lowers TTL ahead of time for zero-downtime transfer.