What is a DNS flush?

DNS flush is the process of manually deleting the temporary entries of a DNS cache. Without a direct intervention in the cache, the entries exist until their defined life span (“time to live”, TTL) has expired.


What is the DNS cache?

DNS servers are used to convert domain names such as www.example.com into numerical addresses. These “name servers” are contacted by default via the browser each time the corresponding projects are accessed, which slightly increases their loading time and can also lead to a DNS server overload in the case of a high number of visitors. Error messages like “DNS Server Not Responding” are a common and despised consequence.

For this reason, operating systems like Windows and macOS attach their own cache for accessed and resolved addresses – the DNS caches. These save all information that’s relevant for name resolution such as an IP address, host names and protocol versions. Each entry remains valid for a given time. Within this time, corresponding queries are answered directly from the cache without requiring a detour to the DNS server.


How to flush your local DNS cache:

1) Call the command line by using the keyboard combination [Windows] + [R].  This will open up the "Run" dialog:

2) Type "cmd" in the "Open" prompt and click "OK."

3) At the Command Prompt, enter the following command and hit the "Enter" key:

ipconfig /flushdns


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