DNS resolves domain names into IP addresses, eliminating the need for people to memorize numeric IP addresses when accessing websites. To expedite this process and reduce traffic on DNS servers, most computer operating systems store or cache DNS lookups locally. Occasionally, clearing this cache is necessary to see updated information. This tutorial will demonstrate how to clear the DNS cache for the major operating systems available, a process commonly known as clearing or flushing the local DNS cache.
Flushing the Local DNS Cache on Windows:
**Windows 11:**
1. Click the search box on the taskbar.
2. Type "powershell" in the search box.
3. Click the Windows PowerShell app to open it.**Windows 10:**
1. Click on the Start Menu.
2. Type "cmd" in the search box.
3. Click the Command Prompt app to open it.**Windows 7 and Vista:**
1. Click on the Start Menu.
2. Type "cmd" in the search box.
3. Right-click on "cmd" in the programs search results and choose "Run as Administrator".**Windows 98/NT/2000/XP:**
1. Click on the Start Menu.
2. Select "Run".
3. Type or select "cmd" to open the command line window.
Once the command line window is open, type the following command at the prompt and hit enter:
ipconfig /flushdns
After completing the flush dns, type "exit" to close the command line window.
Flushing the Local DNS Cache on Mac OS X:
**OS X 10.10:**
1. Open a Terminal window.
2. Type the following command and hit return:sudo discoveryutil mdnsflushcache
3. Close the terminal window.**OS X 10.7 – 10.9:**
1. Open a Terminal window.
2. Type the following command and hit return:sudo killall -HUP mDNSResponder
3. Close the terminal window.**OS X 10.6 and below:**
1. Open a Terminal window.
2. Type the following command and hit return:sudo dscacheutil -flushcache
3. Close the terminal window.
Flushing the Local DNS Cache on Linux:
With the various distributions of Linux, you will find that some run a daemon in the background to manage DNS cache, while others do not. Ubuntu is a good example of a distribution that doesn’t run this daemon by default. If you’re running Ubuntu and you have not already installed the nscd daemon, you can install it by running this command:
sudo aptitude install nscd
To restart the nscd daemon in Linux, run this command:
sudo /etc/init.d/networking restart
