DNS cache on Mac Generally, flushing out DNS on a Mac is unnecessary, but in many cases, it can help to solve some Internet connection problems on your computer.
What is a DNS? DNS (Domain Name System) is a distributed system for storing information about domains and providing it at the users’ request. The DNS links the IP address of the host, which contains the necessary data, and the domain itself.
What is a DNS cache and should you clear it? DNS Cache is a database that contains temporary records of all recent visits and attempts to visit websites and other IP addresses of websites. “Flushing” the DNS cache means clearing the database of websites’ IP addresses the user visited. It is safe to flush the DNS cache. However, there is no need to refresh DNS without a reason for this.
When should you flush DNS cache? You should flush DNS in the following cases: When the DNS settings have been changed and the page does not load. When you need to remove a specific server or domain cached data. When you encounter any other issues with displaying websites.
How to clear the old DNS cache In the Terminal’s window, type the command below:
For macOS High Sierra and later sudo killall -HUP mDNSResponder
For macOS El Capitan sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder