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What is TTL and How Does It Affect DNS Changes?
TTL controls how long DNS resolvers cache your records, and managing it correctly makes DNS changes faster and safer.
TTL (Time to Live) is a number attached to every DNS record that tells resolvers how long to cache that record before checking for a fresh copy. Getting it right is one of the simplest ways to make DNS changes go smoothly.
What TTL actually does
When a visitor's browser looks up your domain, a DNS resolver fetches your records and stores them locally for the duration of the TTL. During that time, the resolver serves the cached copy rather than querying your nameservers again. Once the TTL expires, the resolver fetches a fresh copy.
TTL is measured in seconds. A value of 3600 means one hour; 86400 means 24 hours. You can see and edit TTL values for each record in the Zone Editor in cPanel.
TTL controls how long other resolvers cache your records. It does not affect how quickly your own nameservers update - that is instant.
Why TTL matters when you make a change
If you change an A record while the old value is cached with a TTL of 86400, some visitors may still be directed to the old IP address for up to 24 hours. Resolvers around the world will each wait out their own remaining cache time before fetching the new value.
This is closely related to DNS propagation - the process by which updated records spread across the internet. A high TTL extends propagation time; a low TTL shortens it.
Practical TTL values
| Situation | Recommended TTL |
|---|---|
| Normal, stable records | 3600 (1 hour) or 86400 (24 hours) |
| Before a planned change | 300 (5 minutes) |
| During active troubleshooting | 60-300 (1-5 minutes) |
| After a change is confirmed | 3600 or higher |
Very low TTLs (under 60 seconds) are rarely necessary and increase the query load on your nameservers. We recommend 300 as the lowest practical value for most situations.
How to lower TTL before a planned change
Lowering TTL in advance is the single most effective thing you can do to reduce disruption when you move a site, change a mail server, or repoint a domain.
- Log in to cPanel and open the Zone Editor.
- Find the record you plan to change - typically an A, AAAA, or MX record.
- Click Edit and change the TTL to
300. - Save the record.
- Wait for the current TTL to expire before making the actual change. If the record had a TTL of 86400, you need to wait up to 24 hours for all resolvers to pick up the lower value.
- Make your DNS change once the waiting period is complete.
Step 5 is the step most people skip. Lowering the TTL only helps once the old cached value has expired everywhere. Set the lower TTL at least as many seconds in advance as the current TTL value.
How long to wait after making the change
Once you have made your DNS change, wait for the new low TTL (for example, 300 seconds) to expire before assuming the change is live everywhere. In practice, allow 10-15 minutes to be safe, as some resolvers may have cached the record just before you changed it.
You can check propagation progress using a tool such as whatsmydns.net to see which resolvers around the world are returning the new value.
If you are testing locally, remember that your own computer also caches DNS. Flushing your local DNS cache ensures you are seeing the live record rather than a stale copy.
Restoring TTL after a change
Once you have confirmed the change is working correctly, raise the TTL back to a sensible long-term value. We recommend 3600 (one hour) as a good default for most records. Leaving TTL at 300 indefinitely creates unnecessary query load and offers no benefit once a record is stable.
- Open the Zone Editor in cPanel.
- Edit the record you changed.
- Set the TTL back to
3600or86400. - Save the record.
Common mistakes to avoid
- Lowering TTL at the same time as making the change. The lower TTL only helps if it was already in place and cached before the change. Doing both at once gives you no benefit.
- Not waiting out the old TTL. If your record had a 24-hour TTL and you lowered it five minutes before your change, most resolvers will still cache the old value for nearly 24 hours.
- Forgetting to raise TTL afterwards. A permanently low TTL increases DNS query volume and can slow resolution slightly for some visitors.
- Changing TTL on records you are not touching. Only lower the TTL for the specific records you plan to change. Lowering everything adds unnecessary load.
- Expecting instant propagation even with a low TTL. A TTL of 300 means up to five minutes, not zero. Some resolvers also ignore very low TTLs and enforce their own minimum.
TTL and email records
MX records follow exactly the same TTL rules. If you are moving email to a new provider - for example, pointing email to Google Workspace - lower the MX record TTL at least 24 hours before the switch, then change the record once the low TTL has propagated. This minimises the risk of mail being delivered to the old server during the transition.
For guidance on the full range of DNS record types and what each one does, see our introduction to DNS record types.