Checker Inputs
Enter a domain, select a DNS record type, and optionally compare results against an expected value.
Example Data Table
| Checkpoint | Domain | Record Type | Returned Value | TTL | Status | Comparison |
|---|---|---|---|---|---|---|
| Resolver Snapshot 1 | example.com | A | 93.184.216.34 | 300 | Visible | Match |
| Resolver Snapshot 2 | example.com | A | 93.184.216.34 | 300 | Visible | Match |
| Resolver Snapshot 3 | example.com | A | Old address cached | 1800 | Visible | Mismatch |
Formula Used
1. Propagation Score
Propagation Score = (Matching Snapshots / Total Snapshots) × 100
If no expected value is entered, the tool uses visible snapshots instead of matching snapshots. This gives a practical visibility score.
2. Consistency Index
Consistency Index = (Stable Matching Results / Total Snapshots) × 100
A higher consistency index suggests that cached answers are aligning across checks, which usually means the change is settling.
3. Average TTL
Average TTL = Sum of TTL Values / Number of Snapshots
TTL estimates how long resolvers may keep old answers. Higher TTL values often mean slower visible propagation.
4. Estimated Cache Window
Estimated Cache Window = Average TTL / 60
This converts average TTL seconds into minutes. It helps explain how long stale records may remain visible.
How to Use This Tool
Enter the domain you want to verify. Select the record type you changed, such as A, MX, or TXT.
Add an expected value when you want direct comparison. Examples include an IP address, mail server, or canonical hostname.
Click Check Propagation. The tool runs DNS lookups and prints the result block above the form.
Review the metrics, returned values, TTL values, and comparison status. Use the graph to spot low confidence or inconsistent visibility.
Download the result table as CSV for spreadsheets. Use the PDF button when you need a printable report.
For stronger validation, repeat checks after the TTL window has passed. DNS caches do not update instantly everywhere.
Frequently Asked Questions
1. What does DNS propagation mean?
DNS propagation is the period when updated DNS records spread through recursive resolver caches. Some users see new records quickly, while others still receive cached older answers.
2. Why can propagation appear slow?
High TTL values delay visible updates because resolvers keep cached answers until they expire. Network providers and device-level caches may also extend the delay.
3. Does this checker test every resolver worldwide?
No. This page checks DNS visibility from the hosting server resolver and evaluates consistency from returned records. It gives a practical validation view, not a full global resolver audit.
4. Should I enter an expected value?
Yes, when you know the target record. Expected values let the checker calculate direct match quality instead of simple visibility, which makes the propagation score more useful.
5. Which record types work best here?
A, AAAA, CNAME, MX, NS, TXT, and SOA are supported. A and CNAME are common for website changes, while MX and TXT are often used for mail updates.
6. What does TTL health represent?
TTL health is a simple scoring aid. Lower average TTL often means caches refresh sooner, while very high TTL can slow visible changes and reduce agility during migrations.
7. Why might I see a mismatch?
A mismatch usually means the returned record does not equal the expected target. It may indicate stale cache, typing errors, old DNS zones, or an incomplete update.
8. When should I recheck propagation?
Recheck after part or all of the TTL window has passed. That gives caches time to expire and often produces a clearer consistency result.