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Clearing Your OS & Browser DNS Cache or How to Flush DNS
Note: The info below clears your global Operating System DNS cache. Many browsers also cache DNS, but reset that Cache after a restart. Firefox does not always do this. Info on how to fix that is below.
Windows® 8
- Press Win+X to open the WinX Menu.
- Right-click on Command Prompt and select Run as Administrator.
- Type the following command and press Enter: ipconfig /flushdns
- If the command was successful, you will see the following message:
- Windows IP configuration successfully flushed the DNS Resolver Cache.
Windows 7
- Click the Start button.
- Enter cmd in the Start menu search field.
- Right-click on Command Prompt and select Run as Administrator.
- Type the following command and press Enter: ipconfig /flushdns
- If the command was successful, you will see the following message:
- Windows IP configuration successfully flushed the DNS Resolver Cache.
Windows XP, 2000, or Vista®
- Click the Start button.
- On the Start menu, click Run....
- If you do not see the Run command in Vista, enter run in the Search bar.
- Type the following command in the Run text box: ipconfig /flushdns
MacOS® 10.7 and 10.8
- Click Applications.
- Click Utilities.
- Double-click the Terminal application.
- Type the following command:
- sudo killall -HUP mDNSResponder
- ALERT! Warning: To run this command, you will need to know the computer's Admin account password.
MacOS 10.5 and 10.6
- Click Applications.
- Click Utilities.
- Double-click the Terminal application.
- Type the following command: sudo dscacheutil -flushcache
Specific Browser Caching
Firefox
We have found that Firefox can be especially aggressive about DNS caching. Here is some info that may help:- type about:config in Firefox’s address bar
- acknowledge the warning that appears next
- find an entry called network.dnsCacheExpiration and set it’s value to 0
- if there’s no such entry, create a new integer item with the name above and a value of 0
- now go back and change the value to 3600
Other Browsers
The OS level DNS cache clearing should work for all other browsers.