Understanding how to effectively manage your DNS cache can be exceptionally beneficial, whether you’re dealing with slow browsing speeds or updating a website’s server. This article breaks down the complex elements surrounding DNS cache, from its very purpose to the ways you can clear it from different browsers, including Google Chrome, Mozilla Firefox, Safari, and Internet Explorer.
In addition, Gain insight into the mechanisms of Time-To-Live (TTL) and DNS propagation, so you can estimate the time it will take for your DNS changes to take effect. Finally, equip yourself with the skills to combat any troubleshooting issues that may arise after a DNS cache clearing.
What Is DNS Cache In Browsers?
DNS cache refers to the temporary storage of information about previous DNS lookups on a machine’s operating system or web browser. DNS (Domain Name System) is like the phonebook of the internet, translating human-friendly website names into IP addresses that computers can understand. Storing this information in a DNS cache makes the process of loading frequently visited websites quicker, as your machine doesn’t have to reach out to the DNS server with every request.
Reasons To Use DNS Cache
A significant reason why DNS Cache is used is to speed up the browsing process. Every time you visit a webpage, a DNS query is performed to find the IP address associated with the site’s name. When DNS caching is employed, the original DNS lookup is stored, so the next time you visit the same site, the DNS lookup time is skipped, which can save time and bandwidth.
Why Clearing DNS Cache Becomes Necessary?
However, there might be several scenarios where clearing the DNS cache becomes necessary. For example, if a website has moved servers and you’re still ending up on the old site due to your DNS cache, you’ll want to clear it. Technical difficulties, such as ‘bad requests’ and other server-type errors, could also prompt a cache clearance. Additionally, you might also need to clear your DNS cache for security reasons, such as threats or DNS spoofing attacks designed to ‘trick’ your cache.
How To Clear DNS Cache In Browsers
Clearing DNS Cache on Google Chrome
- Open Google Chrome.
- Type “chrome://net-internals/#dns” in the URL bar and press Enter.
- This will take you to Google Chrome’s DNS page. There, click on the “Clear host cache” button.
Clearing DNS Cache on Mozilla Firefox
- Open Firefox and type “about:config” in the address bar. Press Enter.
- You will receive a warning that says “Proceed with Caution.” Accept the risk and continue.
- In the search box, type “network.dnsCacheExpiration” and make sure it is set to zero.
Clearing DNS Cache on Safari
- Launch the Safari browser.
- Go to the Safari menu and select the “Clear History” option.
- From the drop-down menu, choose “all history” and press the “Clear History” button. This will clear the DNS cache on Safari.
Clearing DNS Cache on Internet Explorer
- Click on the “Tools” option located on the top right corner of the browser.
- Now, select “Internet Options” from the drop-down menu.
- In the new window, under the “General Tab” find and click on the “Delete” button. This button is located under the “Browsing History” section.
- A new window will open.
- Check the box with the option “Temporary Internet files and website files” and click on “Delete.”
Tip To Remember: These processes to clear dns cache in browsers may differ slightly based on the version of the browser you are using, but the general principles for each browser remain the same.
Time-To-Live (TTL) and DNS Propagation
Understanding the Significance of TTL
Time to Live, commonly known as TTL, is an essential concept to grasp when dealing with domain name system (DNS) settings. The TTL is essentially a countdown clock specifying the length of time that a DNS record is approved to be cached, or stored temporarily, by servers, routers, and other systems. In other words, the TTL number defines the lifespan of the data in cache.
Different DNS records might have varying TTL values. For example, a DNS record with a TTL of 3600 seconds, or one hour, means that servers will store the record’s information for one hour before checking if changes have been made. If a change is made within that hour, servers won’t recognize it immediately as they’re relying on the cached, or stored, data until the hour has passed. After the cache duration expires, servers request the latest updates, which then replaces the old cache.
A longer TTL value reduces the frequency of requests made to an authoritative DNS server, which can be ideal for static network environments. However, longer TTL values mean changes to DNS records take longer to propagate. Lower TTL values, on the other hand, are suitable for dynamic networks where changes are frequent, but can lead to increased DNS traffic.
Grasping the Concept of DNS Propagation
DNS Propagation is another crucial element of the DNS infrastructure. It refers to the time it takes for updates or changes made to your DNS records to be updated across the internet. When a modification is made to a DNS record, that change isn’t instantaneously recognized everywhere.
The update needs to spread or ‘propagate’ to all other servers and directories across the web. This propagation period depends on the TTL set for the DNS record. While TTL is the primary driver, other factors like network latency, server configurations, or even internet service provider policies can influence the propagation delay.
Understanding DNS propagation is crucial as during this period, some users might be redirected towards the old IP address, while others towards the new IP, creating an inconsistent experience.
Troubleshooting After Clearing DNS Cache
DNS Cache Issues
DNS (Domain Name System) cache is a temporary database maintained by a computer’s operating system that contains records of all the recent visits and attempted visits to websites and other internet domains. Certain issues can sometimes arise after clearing DNS cache, such as slow load times or having a hard time reaching certain websites.
Common Problems Post-Clearing DNS Cache
One of the most common issues after clearing DNS cache is the delay in web pages loading. When you clear your DNS cache, your computer will need to request new IP addresses for any websites you visit, which might slow things down for a little while. You might also experience issues with reaching specific websites. This could be due to the website’s DNS records having been updated recently after you cleared your cache, making the website temporarily unavailable.
How to Resolve Post-DNS Cache Clearing Issues
To resolve any issues that may come up after clearing your DNS cache, try reloading the page or checking back at a later time if you are trying to reach a specific website. Sometimes, clearing your DNS cache again can help, or even resetting your network settings if the issue continues. Make sure you are using a reliable Internet Service Provider (ISP), as they play a major role in your internet’s speed and reliability.
Consider setting up secondary DNS servers, which can handle requests if your primary DNS server is down. This can significantly improve your internet’s reliability and speed.
If you continue to see the same issues even after trying all these methods, it might be a more critical problem with your ISP, and you should consider contacting them or seeking professional help.
In case of slow loading times, understand this is a temporary issue that will fix on its own. This is simply because your system has to re-cache all the frequently used websites and related IP addresses, which can take a little time initially.
Patience is key here. Once the system has re-cached the commonly visited websites, the loading speed will be back to normal. You should also make sure that your browser is updated and does not contain any malicious add-ons which could be affecting speed.
Note: Clearing your DNS cache is a helpful measure to solve many network-related issues. However, always remember to safeguard your personal and private information online. Avoid clicking on suspicious links and ensure that you are browsing via secured and reliable networks only.
Now that you have delved into the intricacies of DNS cache, its clearance, and subsequent troubleshooting, you are now well-prepared to manage and resolve any related issues effectively. By understanding the steps to clear DNS cache from multiple browsers, the principles of Time-To-Live (TTL) and DNS propagation, you have a comprehensive command of the processes tied to DNS cache. You are now not only able to enhance your browsing experience but also have the requisite knowledge to address any unprecedented problems post clearing your DNS cache.
Nishant Verma is a senior web developer who love to share his knowledge about Linux, SysAdmin, and more other web handlers. Currently, he loves to write as content contributor for ServoNode and also collaborated with MRLabs now.