Flush DNS

Modern browsers, OS and DNS clients will cache IP addresses and other DNS information automatically.When a computer visits a website for the first time, it stores the website's DNS information in cache. The next time the computer visits a website, it looks in the cache to see if the website's information is present to use. This can cause problems if the website's DNS information has changed since the computer's last visit. Flushing the cache removes all the information stored in cache, forcing the computer to find the new DNS information for the website. Usually it is done in order to speed up the process and minimize requests for same hostnames. When IP addresses are changed or bad resualts are cached, its necessary to clear the DNS cache. DNS cache can be cleared via command line or from browsers also. Steps to flush DNS Cache for major operationg systems and browsers are explained.


Windows 8/ Windows 8.1 DNS Flush

Because of the system security policies run cmd as administrator user and follow below steps to flush DNS cache


  1. Press Windows key + X and select the Command Prompt (Admin) option from the Power User menu.
  2. Type in the command ipconfig /flushdns

Windows Vista / Windows 7 Flush DNS

To flush DNS on upgraded version of Windows is almost as easy as it is in the previous versions but due to Microsofts upgraded security system requirements you must run the command prompt with administrator privileges.


  1. To flush DNS through the command prompt, navigate as shown (Start > All Programs > Accessories > Command Prompt)
  2. to have administrator privileges you must do right click on the command prompt application and choose "Run as Administrator"
  3. Type in the command ipconfig /flushdns


Short-cut

Type in cmd into the Windows Vista / Windows 7 start menu search field and then right click on the cmd.exe result instead of navigating through the various sub menus.



Windows 98/NT/2000/XP Flush DNS

Given below steps will help you to clear your windows DNS cache .


  1. To access command prompt (Start > Run > ).
  2. Type the cmd and hit Enter
  3. In the CMD window that you just opened, Type in the command ipconfig /flushdns


Mac OS X Flush DNS

Flushing the DNS in Mac OS X is an easy process, but the steps taken will depend on which version of OS X is running as your operating system.

Mountain Lion or Lion

If you are using Mac OS X 10.7 or 10.8, as your operating system you need to do the following:

  1. Access the command terminal.
  2. Run the following command in the terminal sudo killall -HUP mDNSResponder

Snow Leopard

If you are using Mac OS X 10.6, as your operating system ,you need to do the following:

  1. Open up a command terminal.
  2. Run the command in the terminal dscacheutil -flushcache

Leopard and below

If you are using Mac OS X 10.5.1 or below as your operating system , you need to do the following:

  1. Open a command terminal.
  2. Run the command in the terminallookupd -flushcache

Linux Flush DNS

If you are running the nscd Name Service Cache Daemon then you will need to do the following.

  1. Open up a command terminal (either as root or run step 2 with sudo )
  2. Run the command in the terminal/etc/init.d/nscd restart