Looking for the definitive article on the supported values of TTL in DNS

Question

I’m looking for the article or other information that describes the MS DNS behavior of TTL==0 records. Our server is a windows 2016 AD DNS server. I’ve been unable to find the information by researching.

Thanks in advance.

Bob

Answer 1

Hi,

Thanks for posting in Q&A platform.

Before we go further, may I know the TTL you mentioned is related DNS server cache or Client cache?

DNS server cache

After a local DNS server resolves a DNS name, it caches the results for the period of time defined by the time to live (TTL) value in the SOA record for the DNS zone. The default TTL is one hour. It can be configured in DNS server console as the following screenshot:

Or you could configure it via PowerShell command e.g. Set-DnsServerCache -MaxTTL 02.00:00:00 -MaxNegativeTtl 00.00:20:00 this command sets the the maximum TTL to 2 days and the maximum negative TTL to 20 minutes.

For more details, please refer to the following link:

Set-DnsServerCache

DNS client cache

The time to live, or TTL, specifies how long each record is cached by clients before being required. If configured as 0, the client will send out a query every time when name resolution is required. This can be configured through DNS console as the following screenshot:

Or you could refer methods in the following official article:

Disable DNS client-side caching on DNS clients

Best Regards,
Sunny

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