Question:
What does TTL mean? Why is my updated DNS record not directly visible and resolving online?
Answer
TTL stands for "Time To Live".
TTL is a value that determines how long a DNS cache server will present the same values before reaching out to the authoritative DNS server and getting a new copy of the record.
This means that once information in the DNS zone is updated, it will not directly be visible online.
In case an existing record is updated, the TTL of that specific record needs to expire, before the new value will be picked up.
In case a new record is added to the zone, the new record should be available rather quickly.
Shorter TTLs can cause heavier loads on an authoritative name server, but can be useful when changing the values of critical services and therefore are often lowered by the DNS administrator prior to a service being moved or updated, in order to reduce possible disruptions.
Available TTL values in The Openprovider Control panel:
- 15 minutes
- 1 hour
- 3 hours
- 6 hours
- 12 hours
- 1 day
In case you want a different TTL value, please use the API and set the TTL according to your own wishes (current minimum supported value is 600 seconds).
What to do if the update is not processed after the TTL is expired?
If the nameservers do not reflect the changes of your zones (for example after updating an IP address of an A record) you might want to flush Google public DNS cache for that specific record.
Google has published a special tool which can help on https://developers.google.com/speed/public-dns/cache. If your record is still not visible after that, please check this article
When you change the TTL of a record it will take the previous TTL time + 1 hour before it is synced on all the nameservers op Openprovider.
Can Openprovider help speed this up further?
Unfortunately, no. Openprovider can not speed up the DNS resolving.
Unfortunately the TTL is not always implemented perfectly by all resolvers, so it might be that they serve the cached value, even after expiration of the TTL. That is not something you can control. If this happens on your local machine (e.g. your laptop or desktop), it may help to flush your local DNS caching.
