160 lines
7.7 KiB
Markdown
160 lines
7.7 KiB
Markdown
---
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page-title: "How to Flush DNS on Mac – MacOS Clear DNS Cache"
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url: https://www.freecodecamp.org/news/how-to-flush-dns-on-mac-macos-clear-dns-cache/
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date: "2024-10-28 11:00:36"
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---
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In this tutorial, you will learn why flushing your DNS cache is important, and how you can clear the cache on your local system.
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Here is what we'll discuss in this guide:
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1. [What is DNS cache?](https://www.freecodecamp.org/news/how-to-flush-dns-on-mac-macos-clear-dns-cache/#intro)
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1. [Why flushing DNS cache is important](https://www.freecodecamp.org/news/how-to-flush-dns-on-mac-macos-clear-dns-cache/#why)
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2. [How to flush DNS cache on MacOS](https://www.freecodecamp.org/news/how-to-flush-dns-on-mac-macos-clear-dns-cache/#howto)
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1. [How to access the terminal application on MacOS](https://www.freecodecamp.org/news/how-to-flush-dns-on-mac-macos-clear-dns-cache/#terminal)
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2. [How to clear DNS Cache for your MacOS version](https://www.freecodecamp.org/news/how-to-flush-dns-on-mac-macos-clear-dns-cache/#version)
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## What is DNS Cache?
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DNS acts much like an internet phonebook. Think of what a phonebook does – it maps a person's name to their respected phone number.
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DNS (short for Domain Name System) maps domain names to their associated IP addresses.
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A domain name, such as `freecodecamp.org`, is easily read, understood, and recalled by humans.
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IP addresses (IP is short for Internet Protocol) is an address that is machine-readable and consists of a unique series of numbers. These numbers identify a device connected to the Internet.
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Their format is not that human-friendly since it is hard to remember an exact sequence of numbers each time you want to visit a website.
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DNS then maps `freecodecamp.org` to its associated IP address - `104.26.3.33`.
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Think of the DNS cache as a local storage area on your Mac.
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It temporarily stores and keeps track of your computer's activity records like recent website visits.
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Each time you visit a website by typing its URL (short for Uniform Resource Locator), the DNS cache will save the IP address associated with that website.
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When you visit that same website for the second time, the lookup process is more efficient, and the lookup time is much shorter.
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It helps save significant time.
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### Why Flushing DNS Cache Is Important
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You should flush the DNS cache for a few reasons.
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The two most important ones are:
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1) **Flushing DNS is a helpful step for troubleshooting Internet connectivity issues**.
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You may be getting DNS errors in your browser, such as the 'DNS Server Not Responding' message when trying to access a site and establish a connection.
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Keep in mind that your local cache information can become outdated over time.
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When DNS updates happen on a website, your Mac is still using the old, inaccurate information to load the requested page.
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Flushing the DNS cache makes sure cache information is up to date.
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2) **Flushing the DNS cache prevents network security threats, malicious attacks, and DNS cache poisoning from happening**.
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Hackers can access and corrupt your saved DNS cache records.
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For example, they could manipulate and change the IP address associated with a Domain Name of a website you have already visited and map it to a malicious one.
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The next time you request to access that same website, there will be a redirection to a fake and corrupted URL.
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Hackers can request personal and sensitive information, such as credit card numbers, and steal it.
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Frequent flushing of the DNS cache will help prevent this from occurring.
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Clearing the DNS cache on your Mac is a relatively straightforward process, even if you don't have a lot of technical knowledge.
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Here is what you will need:
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- Access to the command line,
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- Your computer password,
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- To enter a text command (the command will depend on the version of macOS you are running).
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### How to Access The Terminal Application on MacOS
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macOS has a built-in CLI (Command Line Interface) named `Terminal.app`, which allows you to enter text-based commands that the Operating System will carry out.
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There are a few ways to open the terminal.
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The easiest way is through Spotlight search.
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For this, you can:
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- Either navigate to the very top right corner of the screen and click on the icon that looks like a magnifying glass.
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- Or, you can also use the `Command Space` shortcut.
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Both will open up the following window:
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From there, start typing `terminal` and click on the `Terminal.app` option that appears.
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You should see a window open that looks similar to the following:
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### How to Clear DNS Cache For Your MacOS Version
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In the terminal window, you will then need to enter a command.
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The command is different depending on the version of macOS you are running.
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Each version of macOS has a version number and a version name.
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To find out the macOS version on your computer, click on the Apple icon at the very top left corner of your screen. From the dropdown menu that appears, select `About This Mac`.
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In the `Overview` tab, you will first see the version name. Then, underneath that, you will see the version number.
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In the table below, you will see the versions of macOS in reverse chronological order – from the most recent one to the oldest one.
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Navigate to your version of Mac and copy the respective command.
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| MacOS Version | Command |
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| --- | --- |
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| macOS 12 (Monterey) | `sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder` |
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| macOS 11 (Big Sur) | `sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder` |
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| macOS 10.15 (Catalina) | `sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder` |
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| macOS 10.14 (Mojave) | `sudo killall -HUP mDNSResponder` |
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| macOS 10.13 (High Sierra) | `sudo killall -HUP mDNSResponder` |
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| macOS 10.12 (Sierra) | `sudo killall -HUP mDNSResponder` |
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| OS X 10.11 (El Capitan) | `sudo killall -HUP mDNSResponder` |
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| OS X 10.10 (Yosemite) | `sudo discoveryutil udnsflushcaches` |
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| OS X 10.9 (Mavericks) | `sudo killall -HUP mDNSResponder` |
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| OS X 10.8 (Mountain Lion) | `sudo killall -HUP mDNSResponder` |
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| Mac OS X 10.7 (Lion) | `sudo killall -HUP mDNSResponder` |
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| Mac OS X 10.6 (Snow Leopard) | `sudo dscacheutil -flushcache` |
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| Mac OS X 10.5 (Leopard) | `sudo lookupd -flushcache` |
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| Mac OS X 10.4 (Tiger) | `lookupd -flushcache` |
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After typing the command and hitting enter, there will be a prompt for entering your computer's password.
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Keep in mind that when you are typing your password, you will not be able to view what you are typing – not even any asterisks.
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It appears as though nothing is happening, but rest assured that something is.
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Once you have entered your password and hit enter, you will not see a message indicating that the process is complete.
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Instead, you will view a new terminal prompt.
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## Conclusion
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And there you have it – your local DNS cache is now clear.
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Hopefully, this has helped resolve any connectivity issues you may be experiencing.
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Clearing DNS frequently is always a good idea to help fix troublesome internet connections and ensure your system is secure from potential threats.
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Thanks for reading!
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---
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---
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