When accessing a website, you typically type in “www.webname.com” into your search bar, but what if I told you that this name is for your understanding only? Computers don’t interpret the names you enter in the search bar. Remember back to primary school computer science: computers operate solely on binary, understanding only 1s and 0s.
This led to the creation of a naming system that allows you to easily access a website while translating that name into something the computer understands. In this case, what the computer understands is an IP Address and what you understand(website name) is called a Domain Name, and what translates these Domain names into an IP address is called the Domain Name System.
To explain further, a domain name system is a naming system that takes alphanumeric domain names and turns them into numeric IP addresses. It translates human-readable web names to their IP address. A domain name has 3 parts to it, which are:
i) Top-Level Domain(TLD): This is the last segment of a domain name appearing after the final dot. In Example.com,.com is the domain name, and it indicates the type or location of the domain. Other examples include .net,.uk, etc
ii) Second-Level Domain(SLD): The second part is located directly to the left of the TLD. In example.com, example is the second-level domain, and it represents the name, business, etc
iii)Sub-Domain: This is the optional part of the domain before the SLD. In blog.example.com, blog is the subdomain and is used to organize different sections of a website or create separate sites under the same domain.
Now I know you’re curious about how the domain name system works, so let me take you through the steps:
i) User Request: This is the moment you enter the website into the search bar, and then a DNS query is initialized.
ii)DNS Resolver: The query is sent to a DNS resolver, which is usually managed by the Internet service provider.
iii)Root Server: The resolver contacts a root server, which directs it to the appropriate TLD(top-level domain) Server.
iv)TLD Server: The server directs the resolver to the authoritative name server for the specific domain.
v) Authoritative Name Server: This server provides the IP address associated with the domain name.
vi)Response: The resolver returns the IP address to your browser, which then connects to the web server to load the website.
So the steps you see are a lot, but it may amaze you that all these happen in split seconds in the background of your search. That is why when you try to access a website, it opens almost immediately. Now it is important to note that all these records are stored in DNS servers, and these records are referred to as DNS records.
A DNS record, also known as a zone file are instructions that live in authoritative DNS servers and provide information about a domain, including what IP address is associated and how to handle requests for that domain. In addition to that, these records consist of a series of text files written in what is known as DNS SYNTAX.
A DNS syntax is a string of characters used as a command to tell the DNS Server what to do. All DNS records have a TTL(Time To Live), which indicates how often a DNS server will refresh the record that has been requested. In case all these felt like plenty of English, just understand that a domain name plus its matching IP address makes up a DNS Record.
Now these DNS records come in different types. We have
- A Record whose function is to connect your domain to a numerical IPv4 address
- AAAA Record, which points the domain to an IPv6 address.
- Cname, which points an ‘A Record’ domain name to another domain name. The Cname in full is Canonical name. An example of an A record could be example.com, and its CNAME will be www.example.com.
- MX Record, which is a mail exchange DNS record that exists when you buy a domain, but you need to add your client-server mail name to the record, so the domain knows which client to use. It needs the chosen client mail server and something called ‘priority value to work’. Also, the lower the number, the higher the priority. You check that you use the website https://mxtoolbox.com/
- TXT Record which provides the ability to associate other services or sometimes your mail service to your domain. They are used for various text-based purposes, predominantly related to email authentication and domain validation.
In this short write-up, I have explained domain name systems, how they work, their types and records. So if you are ever confused about DNS, please use this PDF as a guide, and if you have further questions, please reach out.