How to flush DNS?

Most operating systems and DNS clients will automatically cache IP addresses and other DNS results, this is done in order to speed up subsequent requests to the same hostname. Sometimes bad results will be cached and therefore need to be cleared from the cache in order for you to communicate with the host correctly. All major operating systems allow you to force this process. Outlined below are the common steps you will need to follow in order to flush your DNS cache.

Microsoft Windows

Windows 10

Flushing the DNS cache on Windows 10 is a very easy process. Due to system security permissions, you must ensure that you run the command prompt as an administrator user.

  1. Ensure that you’re on the Windows 10 desktop.
  2. Right-click on the start menu and choose Command Prompt (Admin) from the menu.
  3. Type in the command ipconfig /flushdns

Windows 8 / Windows 8.1

Flushing the DNS cache on Windows 8 and Windows 8.1 is a very easy process. Due to system security permissions, you must ensure that you run the command prompt as an administrator user.

  1. Ensure that you’re on the Windows 8 Start Screen.
  2. Simply type cmd and the Windows search bar will appear on the right-hand side with search results.
  3. Right-click on Command Prompt and click Run as administrator
  4. Type in the command ipconfig /flushdns

Windows Vista / Windows 7

Flushing DNS on newer versions of Windows is almost as easy as the earlier versions but due to Microsoft’s security additions, you must run the command prompt with administrator privileges.

  1. Click the start button and navigate to the command prompt (Start > All Programs > Accessories > Command Prompt)
  2. Make sure that you right-click on the command prompt application and choose “Run as Administrator”
  3. Type in the command ipconfig /flushdns

Note: It is also possible to type in cmd into the Windows Vista / Windows 7 start menu search field and then right-click on the cmd.exe result instead of having to navigate through the various sub-menus.

Windows 98/NT/2000/XP

Flushing the DNS on Windows is an easy process, outlined below is the steps that should be run if you wish to clear your DNS cache.

  1. Open up a command prompt (Start > Run > cmd.exe > OK).
  2. Type in the command ipconfig /flushdns

Apple OS X

Flushing the DNS in Mac OS X is an easy process, but the steps taken will depend on which version of OS X you are running.

macOS Sierra and above

If you are running Mac OS X 10.11, you need to follow the below steps:

  1. Open up the command terminal.
  2. Run the command sudo killall -HUP mDNSResponder

Mac OS X El Capitan

If you are running Mac OS X 10.11, you need to follow the below steps:

  1. Open up the command terminal.
  2. Run the command sudo killall -HUP mDNSResponder

Mac OS X Yosemite

If you are running Mac OS X 10.10, you need to follow the below steps:

  1. Open up the command terminal.
  2. Run the command sudo discoveryutil udnsflushcaches

Mac OS X Mavericks, Mountain Lion, Lion

If you are running Mac OS X 10.9 or 10.8 or 10.7, you need to follow the below steps:

  1. Open up the command terminal.
  2. Run the command sudo killall -HUP mDNSResponder

Mac OS X Snow Leopard

If you are running Mac OS X 10.6, you need to follow the below steps:

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

Mac OS X Leopard and below

If you are running Mac OS X 10.5.1 or below, you need to follow the below steps:

  1. Open a command terminal.
  2. Run the command sudo lookupd -flushcache

Linux

If you are running the nscd Name Service Cache Daemon and wish to flush your DNS cache, 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 /etc/init.d/nscd restart