Updated on 2022-09-22 GMT+08:00

What Is TTL?

TTL is short for time to live. It specifies how long records are cached on a local DNS server.

The local DNS server is connected to clients (computers or smartphones) through the Internet. By default, its address is assigned by the broadband carrier. You can also choose a public DNS server, for example, 114.114.114.114 or 8.8.8.8, as your local DNS server. The local DNS servers for ECSs purchased on Huawei Cloud are private DNS servers. For details, see What Are the Private DNS Server Addresses Provided by Huawei Cloud?

When the local DNS server receives a domain name request, it asks the authoritative DNS server of the domain name for the required resource record, and then caches the record for a period of time. During this period, if the local DNS server receives requests for this domain name again, it does not request the record from the authoritative DNS server, but directly returns a result from the record in its cache.

The length of time resource records are cached on the local DNS server is specified by the TTL value. You can set it when adding record sets in public or private zones. For details, see Managing Record Sets.

The effective time of the following operations depends on the TTL value (to accelerate the process, decrease the TTL value):

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