How to Flush DNS Cache to Improve Website Loading Speed and Troubleshoot Network Problems

Mar 4, 2024 | How to, Blog, Troubleshooting | 0 comments

Have you ever tried to visit a website but kept getting an error page? Or found that pages load slowly or assets like images don’t load even though your internet seems fine?

An outdated DNS cache could be the culprit. DNS (Domain Name System) is like the internet’s phone book, translating domain names to IP addresses. Your device caches these DNS records locally so you don’t have to look up every site on each visit.

But sometimes these cached records become stale or incorrect, leading to connectivity issues even when the rest of your internet is working properly.

Clearing this cached data forces your system to do a fresh DNS lookup and can fix certain browser and network errors. According to a 2022 survey, around 72% of companies reported experiencing DNS related issues that were resolved by flushing the DNS cache. Keep on reading this article to learn how to flush your DNS cache on Mac, Windows, Linux, and other devices.

What is DNS and why is it important?

The Domain Name System (DNS) is a key part of the Internet’s infrastructure. DNS is considered one of the internet’s core protocols and serves a vital purpose – it translates domain names that humans can easily remember (like example.com) into the numerical IP addresses (like 192.168.1.1) that computers use to identify each other on a network.

Without DNS, you would have to remember all website and server addresses as a series of numbers, which would be extremely difficult. DNS servers act as the internet’s phone books by maintaining a directory of domain names and their corresponding IP addresses.

When you type a web address into your browser, your computer sends a DNS query to a DNS server to resolve, or translate, the domain name into an IP address so it can retrieve the website. The DNS server then responds with the IP address associated with that name.

Some key reasons why the DNS system is so crucial for the internet:

  • It enables the use of human-friendly domain names rather than hard-to-remember numeric IPs.
  • It distributes the process of resolving domain names across a global network of DNS servers.
  • It provides redundancy in case of DNS server failures.
  • It allows for load balancing of traffic across content delivery networks.
  • It makes it easy to route traffic globally and locate services by name.
  • It enables reliable access to websites and internet-connected resources.

In short, without DNS providing the critical service of turning names into numbers, it would be extremely difficult to access websites and internet services we rely on.

What is DNS cache and why should you flush DNS cache?

Your device stores DNS records in a DNS cache to improve performance. This cache contains recently requested DNS lookups, allowing your browser to access frequently visited sites faster without having to perform a DNS lookup each time.

However, sometimes this DNS cache can get cluttered with outdated or invalid entries, which can cause connectivity issues like not being able to load certain websites. Clearing your DNS cache forces your device to do a fresh lookup for DNS records rather than relying on old cached data.

Common reasons to flush your DNS cache

  • You recently changed DNS server settings but are still reaching old IP addresses. Flushing the cache will allow you to use the new DNS servers.
  • You suspect your ISP or external DNS server is providing incorrect information. Flushing can force a lookup from a different, accurate server.
  • A site you frequently visit has changed its IP address but you still reach the old one. Clearing the cache fetches the new IP.
  • Pages aren’t loading properly or you get browser errors indicating DNS issues. A flushed cache may resolve browser problems.
  • You switched networks or internet connections and want your device to repopulate its DNS cache.
  • You’re troubleshooting connectivity issues and DNS seems a likely culprit. Flushing can eliminate DNS as the issue.
  • You made hosted zone changes on Route 53 or a similar DNS control panel and need clients to reflect these updates immediately.

In summary, flushing your DNS cache can help resolve page load errors, site access issues, and other connectivity problems caused by invalid entries in your DNS cache. It’s a useful troubleshooting step when your browser seems unable to reach websites properly.

How to flush DNS cache on Windows 10

Follow these steps to flush your DNS cache on Windows 10:

  1. Open the Windows start menu and search for “Command Prompt”.
  2. Right-click on the Command Prompt application and select “Run as administrator”. This opens the command prompt with admin privileges.
  3. In the Command Prompt, type the following command and press Enter: ipconfig /flushdns
  4. This will immediately clear the DNS cache on your Windows 10 computer.
  5. You can also flush the DNS cache via PowerShell. Open a PowerShell window as administrator and enter: Clear-DnsClientCache
  6. After running either command, close the Command Prompt or PowerShell window.
  7. Restart any internet browsers you have open, or restart your computer, for the DNS flush to fully take effect.

That’s it! With a few simple commands, you’ve successfully flushed your DNS cache on Windows 10. This forces Windows to re-query DNS servers when resolving domain names to eliminate any outdated or incorrect cached DNS records.

How to flush DNS cache on Mac

Follow these steps to clear your DNS cache on Mac:

  1. Open the Terminal application on your Mac. You can find it in the Utilities folder or search for “Terminal” using Spotlight.
  2. In the Terminal window, type the following command and press Enter: dscacheutil -flushcache
  3. This will immediately flush all DNS caches on your Mac.
  4. You can also clear the DNS cache for a specific network interface. First, view your network interfaces by entering: networksetup -listallnetworkservices
  5. Then flush the cache for a specific interface, like Wi-Fi, with: dscacheutil -flushcache -networkservice “Wi-Fi”
  6. Quit the Terminal app when finished.
  7. Restart your web browser or your computer for the DNS flush to fully take effect.

That’s all there is to it! With this simple Terminal command on Mac, you can efficiently flush your DNS cache to troubleshoot internet and browsing issues caused by outdated DNS records getting cached.

How to flush DNS cache on Linux

On Linux, you can flush your DNS cache using these steps:

  1. Open the Terminal application on your Linux distribution.
  2. Enter the following command to restart the DNS caching service and flush the cache: sudo systemctl restart network-manager
  3. Alternatively, you can just flush the DNS cache while leaving the service running with: sudo systemd-resolve –flush-caches
  4. Some distributions may use nscd for DNS caching. Flush nscd’s cache with: sudo /etc/init.d/nscd restart
  5. You can verify the cache was cleared by checking /etc/resolv.conf which contains DNS info: cat /etc/resolv.conf
  6. Any nameserver info shown should now be freshly updated after the flush.
  7. Restart any open applications like web browsers to ensure they use the flushed DNS cache.

Flushing the DNS cache on Linux ensures that any new DNS settings or changes are properly reflected across the system.

How to flush DNS cache on Ubuntu

Ubuntu Linux makes it easy to flush your DNS cache. Follow these steps:

  1. Open the Terminal application on your Ubuntu desktop.
  2. Enter the command to restart the systemd-resolved service which handles DNS caching: sudo systemd-resolve –flush-caches
  3. If your Ubuntu version uses nscd for caching, stop and restart that service instead: sudo service nscd restart
  4. You can verify the DNS cache was cleared by checking the resolve.conf file: cat /etc/resolv.conf
  5. Any nameservers listed will be freshly updated after flushing the DNS cache.
  6. Restart any web browsers and other applications to ensure they use the newly flushed DNS cache.

How to flush DNS cache on Windows 11

Clearing your DNS cache on Windows 11 is very similar to Windows 10:

  1. Open the start menu and search for “Command Prompt”.
  2. Right-click Command Prompt and select “Run as administrator”.
  3. In the admin Command Prompt, enter the command: ipconfig /flushdns
  4. This will immediately flush the DNS cache on your Windows 11 PC.
  5. You can also use PowerShell to flush the cache. Open an admin PowerShell window and typeClear-DnsClientCache
  6. Close the Command Prompt or PowerShell window when finished.
  7. For the new DNS cache to fully load, restart any open browsers or restart your Windows 11 computer.

How to flush DNS cache on Firefox

To flush your DNS cache in the Firefox browser, follow these steps:

  1. Open Firefox on your computer.
  2. In the address bar, type about:config and press Enter.
  3. A warning may appear – click “Accept the Risk and Continue” to proceed.
  4. In the search bar, search for the preference network.dnsCacheExpiration.
  5. Double click on the preference and set the value to 0 to clear the DNS cache.
  6. You can also open Firefox’s Clear Recent History window:
  • Click the Menu button > History > Clear Recent History
  • Make sure “Cached Web Content” is selected
  • Click “Clear Now”
  1. Finally, restart the Firefox browser for the flushed DNS cache to fully take effect.

Flushing Firefox’s DNS cache can help fix page load errors and connectivity issues caused by outdated cached records. For the best browsing experience, remember to periodically clear your Firefox DNS cache.

How to flush DNS cache on Chrome

Follow these steps to flush your DNS cache in the Chrome browser:

  1. Click the three vertical dots in the top right corner to open Chrome’s menu.
  2. Select Clear browsing data (Ctrl + Shift + Del).
  3. In the dialog box that opens, select the checkbox next to “Cached images and files”.
  4. Change the timeframe at the top to “All time”.
  5. Click the Clear Data button to flush the DNS cache.
  6. Close and restart the Chrome browser for the changes to fully take effect.

Alternatively, you can flush the cache via Chrome’s command line:

  1. Type chrome://net-internals/#dns in the address bar and press Enter.
  2. Click the Clear host cache button to flush the DNS cache.
  3. Restart Chrome.

Flushing Chrome’s DNS cache helps resolve issues caused by outdated website DNS records being cached.

What are the Commands to flush the DNS cache?

The main flush DNS cache commands on the most common operating systems are:

1. Windows

  • ipconfig /flushdns (in Command Prompt)
  • Clear-DnsClientCache (in PowerShell)

These commands clear the cache for all network interfaces on Windows.

2. MacOS

  • dscacheutil -flushcache

This flushes all DNS caches on MacOS.

3. Linux

  • sudo systemctl restart network-manager
  • sudo systemd-resolve –flush-caches
  • sudo /etc/init.d/nscd restart

These flush the DNS cache on Linux distributions using systemd, systemd-resolved, or nscd.

4. Ubuntu Linux

  • sudo systemd-resolve –flush-caches
  • sudo service nscd restart

Flushes cache on Ubuntu’s systemd-resolved or nscd.

5. Web Browsers

  • Firefox: set network.dnsCacheExpiration to 0
  • Chrome: clear browsing data for cached images/files

Browser commands clear browser-specific DNS caches.

Knowing these key OS and browser commands to flush DNS can help resolve connectivity issues caused by stale cached DNS records.

Troubleshooting common issues after flushing DNS cache

Flushing your DNS cache is generally safe and straightforward. However, in some cases, it may not resolve your connectivity issues or could even cause new problems. Here are some common issues and fixes:

1. Website still not loading correctly after flushing DNS

  • Try clearing your browser cache in addition to the DNS cache. Browser caching could be serving old site files.
  • Make sure you restart your browser or device after flushing for changes to take effect.
  • The website itself could be having technical issues. Check by trying to access it from a different network.

2. Internet still slow after flushing the DNS

  • Check for other devices using bandwidth on your network. Large downloads in progress could slow things down.
  • Contact your ISP – there could be network congestion or an outage in your area.
  • Check router settings – factors like old firmware, WiFi congestion, or QoS settings could throttle speeds.

3. Getting default search page instead of website

  • Browser DNS settings may be overriding system settings. Update browser DNS configuration.
  • Try accessing URLs by typing the full domain name rather than searching.
  • Clearing browser cache/cookies may help resolve default page issues.

4. Pages not loading, getting “server not found”

  • Try pinging sites to check basic connectivity before DNS lookup. If ping fails, troubleshoot ISP service.
  • Certain sites may be down – check by accessing from devices on different networks.
  • There may be a firewall/parental control blocking access. Temporarily disable to test.

5. Getting a different site after flushing the DNS cache

  • This likely means the site’s IP address changed. The old IP was cached, now you see the updated site.
  • If the different site seems suspicious, your DNS settings could be compromised. Restore defaults or use known good servers.

6. No internet access after flushing DNS cache

  • First, renew the IP and flush DNS on your router to restore internet connectivity.
  • For PCs, review network adapter settings to confirm proper IP, DNS, and proxy config.
  • On mobile, check cellular data is enabled if WiFi is down. Toggle airplane mode off/on to re-establish network registration.

Conclusion

In today’s connected world, we rely on DNS servers to reliably access websites and internet-enabled applications. When DNS issues arise, flushing your system’s cache can force it to repopulate the cache with fresh data from the authoritative DNS source.

This troubleshooting technique applies to all major operating systems and browsers. Learning the quick commands to flush your DNS cache empowers you to proactively resolve DNS-related problems before they seriously disrupt your internet usage and productivity.

As a best practice, periodically flushing your DNS cache helps optimize performance by preventing invalid entries from accumulating over time. Keep these key steps handy so you can efficiently flush your DNS anytime connectivity issues appear.

Article you might be interested in How to Resolve the DNS Probe Finished No Internet Issue

Frequently Asked Questions (FAQs)

Why should I flush my DNS cache?

Flushing your DNS cache forces your device to repopulate it with fresh, updated DNS records which can fix issues caused by stale, incorrect cached entries like not being able to load websites.

How often should I flush my DNS cache?

It’s a good idea to flush your DNS cache about once a month or if you are experiencing any internet connectivity or browsing issues that could be related to DNS.

Does flushing the DNS cache hurt my computer?

No, periodically flushing your DNS cache is a safe operation and does not negatively impact your system. It simply clears out old data.

Will flushing the DNS cache delete my browser history or bookmarks?

No, flushing the DNS cache only clears cached DNS records. It does not affect your web browser history, bookmarks, or any other saved information.

Do I need to be a computer expert to flush the DNS cache?

No, you do not need special skills. This guide provides simple step-by-step instructions to flush the DNS cache on all major operating systems and web browsers.

How long does it take to flush the DNS cache?

It only takes a few seconds to execute the flush DNS cache commands. However, you may need to restart your browser or device for the effects to fully take place.

What happens if I flush the DNS cache and it doesn’t fix the issue?

If flushing your DNS does not resolve internet connectivity or browsing issues, the problem is likely caused by something else and you will need to troubleshoot further or contact your ISP.

Where can I learn more about DNS caching?

There are many useful online resources that provide background details about how DNS works and the role caching plays in speeding up internet access and performance.

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