A DNS cache is just a collection of data that includes the document of recent visits and attempted visits to websites and other internet domains. You need to clear the DNS cache on your MacOS Sierra that may help to solve internet connectivity problems. A DNS cache becomes poisoned or corrupted when there is an insertion of unauthorized domain names or any other IP address.
Resetting a DNS cache clears all the entries, invalid records and allows your Mac to reproduce those addresses when you try to access that website.
How to Reset DNS Cache
1.Just open the Terminal application that can be found in the Utilities Folder
2. The next step is, enter the command syntax
sudo killall -HUP mDNSResponder;say DNS cache has been flushed
3. After entering the command syntax, tap Return/Enter key. Then enter the admin password
(This admin password is necessary for the privacy of sudo).
4. Wait for few minutes till the DNS cache gets cleared. There will be a verbal audio alert confirms that DNS cache has been cleared.
There is an alternative command syntax if the above-mentioned command may not work.
1.Open the Terminal Application and enter the following command.
sudo killall -HUP mDNSResponder;sudo killall mDNSResponderHelper;sudo dscacheutil -flushcache;say MacOS DNS cache has been cleared
2. Now enter the System password and tap Return/Enter key.
These steps will help you to reset the DNS cache in your MacOS Sierra or MacOS High Sierra.