How DNS Propagation Works

What is DNS?

The Domain Name System (DNS) translates human-readable domain names like example.com into IP addresses that computers use to communicate. When you type a domain into a browser, your computer queries a chain of DNS servers to find the IP address associated with that domain.

DNS is a globally distributed, hierarchical database. No single server holds all DNS records for every domain. Instead, responsibility is delegated: root servers delegate to TLD servers (.com, .net), which delegate to authoritative nameservers for each domain.

How DNS Resolution Works

A typical DNS query follows this path:

1. Recursive resolver — your ISP or public resolver (Google 8.8.8.8, Cloudflare 1.1.1.1) receives your query.
2. Root nameserver — tells the resolver which TLD server handles .com.
3. TLD nameserver — returns the authoritative nameservers for your domain.
4. Authoritative nameserver — holds the actual DNS records (A, MX, TXT, etc.) and returns the answer.

The recursive resolver caches this answer for future queries, up to the TTL duration set on the record.

TTL and Caching

Every DNS record has a Time To Live (TTL) value, measured in seconds. This tells resolvers how long to cache the record before requesting a fresh copy from the authoritative server.

example.com.  300  IN  A  93.184.216.34
             ^^^
             TTL = 300 seconds (5 minutes)

Common TTL values:

• 60–300s — used before planned changes; allows fast propagation
• 3600s (1 hour) — a balanced default for most records
• 86400s (24 hours) — used for stable records; reduces resolver load

Lowering TTL before a planned change is standard practice. Set it 24–48 hours in advance, make the change, then raise TTL back after propagation completes.

Propagation Timeline

Propagation is not a server "pushing" your changes to every resolver on the internet. It is simply the natural expiry of cached records across thousands of independent resolvers worldwide.

The time to full propagation is therefore determined by the old TTL on the record before the change, not the new one. If your old A record had a 24-hour TTL, some resolvers may serve the old IP for up to 24 hours after you make the change.

Old TTL	Expected propagation time
300s (5 min)	5–15 minutes
3600s (1 hour)	1–2 hours
86400s (24 hours)	Up to 48 hours

Checking Propagation

You can verify whether your DNS changes have reached specific resolvers worldwide using tools that query multiple public DNS servers simultaneously.

# Check A record via Google DNS
dig @8.8.8.8 example.com A

# Check A record via Cloudflare DNS
dig @1.1.1.1 example.com A

# Check MX record
dig @8.8.8.8 example.com MX

Use the DNS Propagation Checker to query 11 global resolvers at once and see which regions have your new records.

Frequently Asked Questions

Can I speed up DNS propagation?

Not directly. You cannot force other resolvers to flush their caches. The only lever you control is TTL — lower it before making changes so caches expire faster. Google and Cloudflare's public resolvers do offer a flush tool for immediate testing from those specific resolvers.

Why do I see the new IP but my colleague doesn't?

You and your colleague likely use different recursive resolvers (your ISP vs their ISP). Each resolver independently caches the old record until its TTL expires, so different users may see different results during the propagation window.

Does propagation affect subdomains separately?

Yes. Each DNS record has its own TTL, and each is cached independently. An A record for www.example.com and one for api.example.com can propagate at different rates.

What is negative caching?

When a resolver queries for a domain that doesn't exist (NXDOMAIN), that negative result is also cached — typically for the SOA record's minimum TTL. This matters when you're adding a new subdomain: old resolvers may cache the NXDOMAIN for its TTL before they try again.