El Captain and newer:
sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponderYosemite:
sudo killall -HUP mDNSResponderLion, Mountain Lion, and Mavericks:
sudo dscacheutil –flushcacheSnow Leopard:
sudo lookupd –flushcacheTiger:
lookupd –flushcache👉 Overview
What ?
DNS, or Domain Name System, is the protocol on the internet that turns human-comprehensible website names such as google.com into addresses understandable by machines. Flush DNS is the process of clearing and resetting the DNS cache. The DNS cache is a database that stores all recent visits to websites and their IP addresses. Flushing this cache means that all the information stored in it is wiped out. Once this cache is cleared, the computer starts asking for new data from the DNS server, thus potentially speeding up the connection or solving connectivity issues.
Why ?
Flushing the DNS is important for several reasons. Firstly, it can help speed up the connection to a website. When the DNS cache gets too cluttered, it can slow down the computer's ability to connect to the internet. Secondly, it can help resolve issues where a website's IP address has changed and the cache is still using the old IP address. Lastly, flushing the DNS can help with privacy as it removes all records of the websites you have visited recently. Therefore, it is an important tool for any internet user, especially those dealing with slow or unstable internet connections or those concerned about their privacy.
How ?
Flushing the DNS cache is a relatively simple process and can be done on any operating system. On Windows, you simply need to open the command prompt and type 'ipconfig /flushdns' and hit enter. On MacOS, the command varies depending on the version, but for most recent versions, you can open the terminal and type 'sudo killall -HUP mDNSResponder' and hit enter. On Linux, the command is 'sudo /etc/init.d/nscd restart'. After typing these commands, the DNS cache will be flushed and any new connections will require the computer to ask for new information from the DNS server.
When ?
The practice of flushing the DNS cache has been around almost as long as the DNS system itself, which was introduced in 1983. As the internet grew and evolved, so did the need for occasional DNS cache flushing. It's a common practice used by system administrators and savvy internet users alike.