Domain Name Server (DNS) is a decentralized navigation protocol which allows us to access websites. It works like a directory that matches names with numbers. Here, names are domain, and numbers are IP addresses.
In simple words, we send requests to visit a webpage through URL. Then the browser transfers the request to the Internet Service Provider (ISP), and ISP converts the URL to IP addresses and transfer it to DNS. After getting a request, DNS finds the match webserver. Then we get the data to our browser. This is a complex process but it happens within the blink of eyes.
More specifically, two IP addresses are involved here. One is our device IP, and another one is the webserver IP. Our device sends an URL request. Later, it transforms into IP. Here, DNS works like a matchmaker and sends data feedback when it is a valid request.
Apart from these, four DNS servers are involved to perform a human sent request. They are-
- DNS Recursor
- Root Nameserver
- TLD Nameserver
- Authoritative Nameserver
DNS Recursor performs the first task of a request. We can call it a receiver. It is designed to receive queries from the client’s device through a web browser. Recursor makes additional requests to other parts.
After that, Root Nameserver resolves human-readable hostnames into IP addresses. Typically, the Root Nameserver serves as a reference to specific locations. Root Nameserver works like a translator.
TLD Nameserver performs the next task, which is the finding process. It searches for an IP address and hosts the last portion of a hostname. For example- in sudonode.com, the top-level domain server (TLD) is .com.
Authoritative nameserver is the final nameserver which processes the final task. If it has access to the requested record, it will return the IP address to the first process.
If we consider the process with a library, The Recursor can be said as a librarian who is asked to find a book. Root Nameserver can be said as an index of the library that indicates different racks of different types of books. Again, TLD nameserver can be considered as a rack of books. Lastly, Authoritative Nameserver can be thought of as a dictionary on that rack of different books.
Subsequently, DNS stores four types of records, and each has different requirements.
- The A records require Hostname, IP address, and TTL.
- MX records require Hostname, Priority, Mail Server, and TTL.
- TXT record requires Hostname, Content, and TTL.
- CNAME records are used when A record could not be found, and their requirements are similar to A record.