DNS How To Guide
The following guide may help you understand a bit about the basic functionality of DNS. i.e Domain Name System. And how to Flush DNS Cache and to use Windows DNS Tools.
What is a DNS propagation checker?
DNS propagation checker provides a user with the facility to check if your DNS records are propagated in the different locations of the world. The DNS records for billions of websites are stored in hundreds and thousands of DNS servers around the world in different countries and ISPs. Some ISPs provide their DNS Servers for public usage, and some private DNS Server owners provide their servers for getting DNS data publicly.
What is DNS?
The DNS stands for Domain Name System, and according to this system, thousands of DNS Servers globally maintain a record regarding the existing and newly registered domain names. DNS Servers collect the DNS data from Domain Registrars, and this data is then used to provide this data to the public. Whenever a request initiates from any computer to query a domain, the first process to follow is to get it's DNS records. The DNS records tell the IP Address of the server on which the queried domain resides and is set-up. Whenever a domain owner wants to change DNS data, they can do so by updating DNS entries from their registrar admin panel, or the cloud DNS management interface. The DNS Servers queries the domain registrars then and forth for fetching updated DNS data, and after successfully getting the data, they update their database regarding domain DNS data. This data is then passed on to every DNS request made by those users who are using the particular DNS Server IP to get DNS record of any domain. In this whole process, the highest authority is domain registrars, who are responsible for giving updated data to DNS Servers so that they can provide this data to the public.
How DNS Works?
Whenever you open a website for example "Whatmydns.me" in your browser, it queries a DNS server set up by your computer or ISP to resolve the domain name into an IP Address. As soon it gets IP Address, it starts to communicate with the IP to receive the data to show in your browser against the requested Web URL. The data received by request is called response of the webpage. In the whole process of opening a webpage, the most important and first step is the DNS resolution of the requested page. If DNS resolution fails, the browser or machine stops execution and returns an error that it failed to resolve DNS, because, without a DNS, the machine knows no IP to send a request for current domain or webpage.
What is DNS Cache?
The DNS Cache is a cache of the recently requested domains in a browser and is stored by the browser or OS for a specified time. The DNS cache helps browser to save time in requesting the same domain multiple times a day, and each request after the first request to a specific domain is served DNS records from the stored cache. It makes the overall process time-efficient. The only disadvantage of DNS cache is that sometimes a domain owner changes the DNS records and your computer tries to serve DNS records for specified domain from the cache, and this results in a domain to return an error as the IP from cache associated with the DNS against domain is no longer available for the domain.
How to Flush DNS Cache?
If you are trying to access a website and it is not accessible because of the reason that your browser is using your DNS Cache data, you must clean your DNS Cache before retrying to access that site. To Flush your DNS cache, please refer to the following article regarding DNS Cache Flush
Windows DNS Tools
Windows DNS Tools provides many functions regarding how to query DNS records for specific domain. A few commands can help you to see the various types of DNS Records used for many purposes. For example, the nslookup command helps to see IP of name servers of a domain. To view name server IP for particular domain, use the nslookup command in the following way. nslookup www.whatsmydns.me/ ns1.server.com.