DNS Propagation Checker
Check whether your DNS changes have propagated across 100+ global servers in real time. See which regions have updated and which are still cached.
Use DNS Propagation Checker in 4 Steps
What is DNS Propagation?
DNS propagation is the period it takes for DNS changes — such as updating an A record or switching nameservers — to be reflected across all DNS resolvers worldwide. When you update a record at your registrar or DNS host, the change doesn't go everywhere at once.
In reality, DNS doesn't "propagate" outward. What happens is that every DNS resolver on the internet has its own cache of DNS records with a TTL (Time To Live) value in seconds. Until a resolver's cache expires, it continues serving the old data.
How Long Does DNS Propagation Take?
Propagation time depends almost entirely on the TTL value set on your records before the change was made.
| TTL Value | Propagation Time | When to Use |
|---|---|---|
| 300 | ~5 minutes | Pre-migration — lower TTL 24h in advance |
| 3600 | ~1 hour | Standard — good balance of speed and caching |
| 86400 | ~24 hours | Very stable records (common registrar default) |
Why DNS Results Differ By Location
When you run a DNS propagation check, you're comparing answers from multiple resolvers around the world. Each resolver has its own cache, so it's normal to see a mix of new and old values during a change window.
- Resolver cache: Public resolvers, ISP resolvers, and corporate resolvers all cache answers independently.
- Local cache: Your operating system (and sometimes your router) caches DNS too.
- CDN/app caching: Even after DNS updates, your site may look “old” due to CDN or application caches.
Where DNS Can Be Cached (And Why It Matters)
If propagation looks “stuck”, it’s usually because you’re seeing different cache layers. Use this quick model to diagnose what’s actually happening.
A DNS propagation checker is most useful for Layer 2: it shows which resolvers updated and which are still serving cached responses.
A Record Changes vs Nameserver (NS) Changes
Not all DNS updates behave the same. Use the right mental model so you don’t waste hours “waiting for propagation” when the issue is configuration.
- Mostly controlled by the record’s TTL in your DNS zone.
- Best practice: lower TTL to 300 seconds 24h before a migration.
- After change: expect mixed answers until TTL expiry.
- Updates happen in the parent zone (e.g.
.com). - Can appear inconsistent longer across different resolvers.
- Requires both DNS providers to have matching zones during the cutover.
If you’re switching DNS providers, create an identical zone at the new provider before changing NS. After the switch, use DNS Lookup to confirm NS and SOA responses.
Propagation Checklist (Fast Troubleshooting)
- Confirm the record at the source: verify the DNS provider/zone has the intended value.
- Check the authoritative nameservers: ensure they're serving the new record.
- Compare against public resolvers: check Cloudflare (1.1.1.1) and Google (8.8.8.8).
- Flush local DNS: only if your own machine is stuck on old results.
- Wait for TTL: if caches are mixed, time is usually the fix.
Common “Propagation” Traps
example.com vs www.example.com often shows different answers.How to Flush DNS Cache
Flushing DNS only affects your local device. It won’t force the whole internet to update—global resolvers still respect TTL.
How to Verify With dig
If you want to double-check what a specific resolver is returning, use dig:
Verify the Authoritative Nameserver (Best Signal)
If global results are mixed, the fastest way to know whether the change is “real” is to query the authoritative nameserver directly. First find the NS set, then ask one of them:
If the authoritative answer is correct but some regions are still old, you’re simply waiting on recursive caches to expire. If the authoritative answer is wrong, fix the record at your DNS provider first.