Introduction
When your computer visits a website for the first time, it stores the website's DNS information in a local cache. The next time you visit that website, it will first look at this cache for any previous visits. While this is a very efficient method it can cause problems if DNS information has just recently changed. In this case you might want to "flush" your local cache to force your local computer to find this new DNS info.
Instructions
Below are instructions unique to particular operating systems.
Microsoft Windows
Windows 7, 8, and 10
1. Click Start.
2. Enter cmd in the Start menu search text box.
3. Right-click Command Prompt and select Run as Administrator.
4. Run the following command:
ipconfig /flushdns
5. If the command succeeds, the system returns the following message:
Windows IP configuration successfully flushed the DNS Resolver Cache.
Windows XP, 2000, and Vista
1. Click Start.
2. On the Start menu, click Run
3. Run the following command:
ipconfig /flushdns
4. If the command succeeds, the system returns the following message:
Successfully flushed the DNS Resolver Cache.
macOS/Mac OS X
NOTE:
The following instructions may require administrative privileges. If you do not have administrative privileges with the account attempting to run the command, you may use 'sudo' at the beginning of your commands. Running commands this way requires that you know your computer's administrator password and that your user is in the sudoers file.
macOS/OS X 10.10.4+
1. Search for Terminal in the Spotlight search, or click Applications within your Finder. If searched with Spotlight and the Terminal has opened, skip to step 4.
2. Click Utilities.
3. Click Terminal.
4. Run the following command:
killall -HUP mDNSResponder
If the command succeeds, the system does not return any output.
macOS/OS X version10.10.1 - 10.10.3.
1. Search for Terminal in the Spotlight search, or click Applications within your Finder. If searched with Spotlight and the Terminal has opened, skip to step 4.
2. Click Utilities.
3. Click Terminal.
4. Run the following command:
discoveryutl mdnsflushcache
If the command succeeds, the system does not return any output.
macOS/OS X 10.7, 10.8, and 10.9
1. Search for Terminal in the Spotlight search, or click Applications within your Finder. If searched with Spotlight and the Terminal has opened, skip to step 4.
2. Click Utilities.
3. Click Terminal.
4. Run the following command:
killall -HUP mDNSResponder
If the command succeeds, the system does not return any output.
macOS/OS X 10.5 and 10.6
1. Search for Terminal in the Spotlight search, or click Applications within your Finder. If searched with Spotlight and the Terminal has opened, skip to step 4.
2. Click Utilities.
3. Click Terminal.
4. Run the following command:
dscacheutil -flushcache
Linux
Many linux distributions allow you to quickly restart the nscd daemon from the terminal. Run the following command as sudo or root:
/etc/rc.d/init.d/nscd restart