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Managing DNS settings is a delicate matter, which requires special attention for the correct setting of the Time To Live (TTL) of the respective records. The TTL is a fundamental parameter in controlling the frequency of updating DNS information. Too high a TTL value can mean a longer wait time when changes need to be propagated, such as redirecting a domain to a new IP address. Situations like these are common in the professional world, especially when inheriting a domain with a DNS TTL set to one day or more.
We have some configuration of DNS TTLs talked about very exhaustively in this post, however, we believe it is appropriate to disclose emergency procedures to be shared also with our colleagues to avoid significant damage to the customers' business.
Let's imagine, for example, that the Customs and Monopolies Agency has mistakenly blocked a website. While waiting for the resolution of an appeal, which could take months, you might need to redirect the site to a .com domain on a foreign server, using a 301 redirect for all resources on the new domain. In this scenario, it may be necessary to point the old domain's IP to the new server, but this could take up to a week if the old domain's zone TTL is set to 604800 seconds (one week). How then can propagation be accelerated?
The reality is that most Internet users use the DNS of their connectivity providers (TIM, FastWeb, Vodafone, etc.), but a growing number of users, especially on smartphones, are starting to use Google nameservers, OpenDNS and CloudFlare DNS. These services cover about 20% of the entire DNS market. However, the main goal is to avoid a drop in SEO by Google, secondly, to try to lose as few potential customer users as possible.
For this reason, you can "force" flush the DNS cache for the most used DNS services.
What does it mean to flush the DNS cache?
DNS flush is a process that cleans and renews information saved (cached) by authoritative servers (i.e. managers and owners) regarding domains. This is particularly useful when a site changes server and consequently at least in theory also the IP address.
Google DNS, OpenDNS and CloudFlare DNS.
To force flush the DNS cache, you must and can use the functions provided by Google DNS, OpenDNS and CloudFlare DNS.
Google's public DNS, OpenDNS, and CloudFlare are widely used and respected domain name resolution services for their resilience and speed. These services act as translators between IP addresses and domain names, an essential process for surfing the Internet.
Google Public DNS is a free DNS service offered by Google, with the aim of making the web faster and more secure. Launched in 2009, Google Public DNS has earned a solid reputation for its reliability and speed. Google uses anycast technology to route DNS requests to the closest server, thereby reducing latency and ensuring fast response times.
OpenDNS is another very popular public DNS provider. In addition to offering fast and reliable DNS service, OpenDNS also offers security and content filtering features, making it a popular option for households and businesses. OpenDNS also uses anycast technology to ensure fast and reliable response to DNS requests.
Cloudflare DNS, also known as 22.214.171.124, is the latest addition to these services, launched in 2018. Despite its relative youth, CloudFlare DNS has quickly gained popularity due to its blazing speed. CloudFlare claims their DNS service is the fastest in the world, with global average response times significantly lower than other DNS providers. CloudFlare also uses anycast technology to optimize the speed and resiliency of its service.
Anycast technology is a key part of the speed and reliability of these DNS services. With anycast, DNS requests are directed to the closest server in terms of network latency, rather than in terms of physical distance. This means that DNS queries are usually resolved faster, improving browsing speed for the user. Resiliency is also improved, as if a server were to go offline, requests could simply be redirected to another server in the anycast network.
Google Public DNS, OpenDNS, and CloudFlare DNS are all excellent examples of how a public DNS service should work, offering speed, reliability, and additional features like security and content filtering. Their popularity is a testament to the quality of service they offer.
How to force DNS cache flush?
Google DNS: Google provides a public caching service which can be flushed by sending a special request to their server. Visit the Google Public DNS Flush Cache page (https://developers.google.com/speed/public-dns/cache) and enter your domain to begin the process.
OpenDNS: OpenDNS allows you to do a DNS flush through their refresh cache tool. Just go up https://cachecheck.opendns.com/ and enter the domain name.
After pressing “Check this domain”, you will see the “Refresh the cache” option which allows you to start the DNS flush process.
Cloudflare DNS: CloudFlare, also known as 126.96.36.199, offers a similar feature. You can access their cache purge tool through the link https://188.8.131.52/purge-cache/ which is presented in a way that is as spartan as it is efficient.
The Purge Cache tool of 184.108.40.206 allows you to refresh the DNS cache of 220.127.116.11 for domain names. To refresh the cache for a domain name, enter the name for the domain below, choose the DNS record type and then press Purge Cache.
It is important to note that forcing a DNS flush can only accelerate DNS change propagation for those systems that have the ability to be forced such as those listed above. In this case the solution is an immediate solution within a minute. However, the complete propagation of a DNS change worldwide can take from a few hours to a few days, depending on the TTL set and the nature of the network. Flushing the DNS cache can help reduce this time, but it doesn't eliminate it entirely.
Also, flushing the DNS cache won't affect your site's SEO in a negative way, as long as the changes are handled properly. In particular, 301 redirects must be used carefully to ensure search engines understand that your site has moved to a new address. This way, your site will maintain its position in search results and continue to receive traffic.
Managing DNS settings is a key part of maintaining a website, and understanding how to speed up DNS propagation can make all the difference in critical situations. Remember that while DNS flushing can help reduce wait times, planning and managing your DNS settings correctly are the best tools to ensure your site remains accessible and visible, no matter the circumstances.