How to Flush DNS cache on Mac
In this article, we cover the best ways to clear your DNS cache on a Mac, including the different ways you can do that depending on the macOS you are running.
Your DNS cache acts like a memory that your Mac refers to when trying to figure out how to load a website.
Flushing the DNS isn’t a difficult task but the process changes with every new operating system. We’ll walk you through the steps needed to manually reset your DNS on latest macOS versions. But if you like you can fast forward to the automatic solution — with a free tool in CleanMyMac X.
What is DNS cache
So what’s DNS cache? It’s a list of domain names attributed to your last-visited websites. It’s not the same as recent online history. Domain name information is coded in numbers, for example, 18.104.22.168.
For example, when a website migrates to a new domain, its DNS address changes. Naturally, it becomes unreachable as your still Mac relies on the outdated DNS record.
So, DNS cache is a log book that translates this numerical information into human readable website names. After you’ve cleaned the DNS cache you may notice that some websites load slower — that’s perfectly normal. Your Mac has forgot them and is trying to access them from scratch.
How to clear the DNS: The manual way
Before we get started, note that resetting the DNS cache will interrupt active web browsing activity so it’s worth closing your browser before performing a flush.
How to flush the DNS cache on macOS Mojave/Catalina
Are you familiar with Terminal? If not, no problem. All you’ll need to do is launch the Terminal app and paste in a couple of commands.
- Open the LaunchPad in the Dock and type in Terminal in the search bar.
- Enter the following syntax at the command line:
- Press Return, enter your password, and press Return again.
- You should now see a message saying “macOS DNS cache reset.”
- Exit the Terminal.
sudo killall -HUP mDNSResponder; sleep 2;
How to clear the DNS: The easy way
For those who want to get this done quickly, a much simpler alternative to clear the DNS cache on all versions of macOS is CleanMyMac X. This is a staple Mac cleaning solution and this app is notarized by Apple.
Flushing the DNS cache just so happens to be in its arsenal of features to help you do this.
To flush the DNS cache with CleanMyMac all you’ll need to do is download it — you can do that here for free.
- Launch CleanMyMac.
- Click on Maintenance from the sidebar menu.
- Select Flush DNS Cache.
- Click Run.
That’s it. Your DNS is all clear and everything should be back to normal. Or you can try one or more of the following methods.
How to clear the DNS on older macOS versions
The algorithm is the same, only the copy/paste command in Terminal will be different for each OS.
To flush DNS cache on macOS Sierra, paste this:
sudo killall -HUP mDNSResponder;say DNS cache has been flushed
To flush the DNS cache in Mac OS X El Capitan and Yosemite, paste this:
sudo dscacheutil -flushcache;sudo killall -HUP mDNSResponder;say cache flushed
Frequently Asked Questions
When should you flush or reset the DNS cache?
Flushing the DNS makes sense when you can’t open certain websites. Especially if they were perfectly available just a moment ago. You can also try this fix when your network slows down randomly or other network-related issues occur.
What will happen if I flush my Mac’s DNS cache?
Flushing the cache simply updates the entry on your Mac that corresponds to the server address. Next time you try to access this server i.e a website, it will load a bit slower —which is similar to cleaning your browser cache.
What are the alternatives to flushing the DNS cache on Mac?
If the above methods seem too technical, you may try to do a hard refresh in your browser. Another way to refresh outdated DNS entries is to delete browser caches.
Clearing the DNS cache on Mac isn’t something you’ll have to do often but it’s a good way to troubleshoot named server errors. Use the correct command for your operating system and you’ll be able to resolve issues within seconds. If, for whatever reason, the command doesn’t work or you don’t feel confident using the Terminal, CleanMyMac will do the job for you.
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