change TTL for forwarder cache

Question

hello
i have a simple domain controller running on server 2019 with integrated DNS and forwarders
i am facing an issue with a website that changes its ip every hour or so
if i clear cache on the dns server , the website works then stops working when they change the ip
I want to decrease the cache of the dns server so it goes faster to the forwarders

I used this command : Set-DnsServerCache -MaxTTL 00.02:00:00

Would this do the trick ?!
thank you

Answer 1

Hello TarekH

You are in the right direction but to avoid network congestion or server load due to so frequent DNS update, you can use the parameter "-MaxNegativeTtl" to specify the maximum keeping time for records that have returned unsolvable.

"Specifies how long (1 to 2592000 seconds) an entry that records a negative answer to a query remains stored in the DNS cache. The value must be provided as a TimeSpan. The default setting is 15 minutes."

You can also add other fine tunning for your DNS server using the next reference: https://learn.microsoft.com/en-us/powershell/module/dnsserver/set-dnsservercache?view=windowsserver2022-ps

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