We all know how important DNS is to our internet experience, but how much do we really know about it? DNS, or Domain Name System, is the underlying technology that allows us to access websites, email, and other online services. Despite its importance, many of us don’t understand how it works or what it does. In this article, we’ll take a closer look at DNS and explore some of the mysteries behind it.
At its core, DNS is a distributed database system that translates domain names (like example.com) into IP addresses (like 192.168.1.1). When you type a domain name into your browser. Your computer sends a query to the DNS server, which looks up the IP address associate with the domain name and returns it to your computer. This process is known as DNS resolution.
DNS resolution is an essential part of the internet experience, but it can also be a source of confusion. For example, DNS records can cache, meaning that the IP address associate with a domain name can store on your computer and retrieve quickly. This is why some websites seem to load faster than others. The DNS record has already been cached on your computer.
How does DNS work?
At its core, DNS is a distributed database of domain names and their associated IP addresses. When a user types in a domain name, the DNS system looks up the IP address associated with that domain name and directs the user to the correct website.
The DNS system is made up of a hierarchy of servers. At the top is the root server, which is responsible for directing users to the correct Top Level Domain server. The TLD server then directs the user to the correct Second Level Domain (SLD) server. Finally, the SLD server will direct the user to the correct website.
To make this process more efficient, DNS servers cache domain name lookups. This means that when a user types in a domain name. The DNS server will check its cache to see if it already has the IP address associated with that domain name. If it does, it will return the IP address without having to query the root server.
DNS also plays an important role in email delivery. When an email is sent, the sender’s mail server contacts the recipient’s mail server using the domain name associated with the recipient’s email address. The mail server then looks up the IP address associated with the domain name and sends the email to the correct server.
DNS is an essential part of the internet and understanding how it works is key to ensuring that your website and emails are delivered correctly. Understanding the basics of DNS can help ensure that your website and emails are delivered quickly and reliably.
Four different DNS servers are Involved in loading a webpage
DNS Recursor
This server is responsible for caching the IP address. So that it can be quickly retrieve the next time someone requests the domain name. The recursive server also helps ensure that the IP address is up to date by periodically checking with the authoritative server for any changes.
Root nameservers
Root nameservers are an essential part of the DNS and are responsible for providing the global infrastructure for the Internet. They are the first point of contact for any web request and are responsible for routing traffic to the appropriate server.
TLD nameserver
TLD nameservers are responsible for resolving domain names to their associated IP addresses. They must maintain a database of all the domains that are associate with a particular TLD. This database is update regularly to ensure that domain name lookups are as up-to-date as possible.
Authoritative nameserver
This DNS server is known as the authoritative server. This server holds the actual IP address associated with the domain name. When it receives the request from the root server, it looks up the IP address and sends it back.
The 8 Steps of a DNS Lookup
Understanding the 8 steps of a DNS lookup can help you better understand how the internet works and how you can troubleshoot any issues you may encounter. Here’s a look at the 8 steps of a DNS lookup and how they work together to get you to the website you want.
Step 1: A DNS query is sent from the user’s computer to the DNS server
When you enter a domain name into your browser, your computer sends a DNS query to the DNS server. The query contains the domain name you entered and the type of record you’re looking for (such as an A record for an IP address).
Step 2: The DNS server checks its cache for the requested record
The DNS server checks its cache to see if it already has the requested record. If it does, it will return the record to the user’s computer. If not, it will move on to the next step.
Step 3: The DNS server checks its zone files for the requested record
If the requested record isn’t in the DNS server’s cache, it will check its zone files. Zone files are like a database of all the records that the DNS server is responsible for. If the record is in the zone files, the DNS server will return the record to the user’s computer.
Step 4: The DNS server sends a query to the root name servers.
If the requested record isn’t in the DNS server’s zone files, it will send a query to the root name servers. The root name servers are the ultimate authority on the internet and are responsible for keeping track of all the top-level domains (such as .com, .org, and .net).
Step 5: The root name servers send a query to the TLD name servers.
The root name servers will send a query to the TLD name servers. The TLD name servers are responsible for keeping track of all the domain names within a particular top-level domain (such as example.com).
Step 6: The TLD name servers send a query to the authoritative name servers.
The TLD name servers will send a query to the authoritative name servers. The authoritative name servers are responsible for keeping track of the records for a specific domain name.
Step 7: The authoritative name servers send a response to the DNS server.
The authoritative name servers will send a response to the DNS server with the requested record. The DNS server will then cache the record and return it to the user’s computer.
Step 8: The DNS server sends a response to the user’s computer.
The DNS server will send a response to the user’s computer with the requested record. The user’s computer will then use the record to connect to the website or other online services.
These 8 steps of a DNS lookup happen in milliseconds, allowing us to access websites quickly and easily. Understanding how the process works can help you better troubleshoot any issues you may encounter when trying to access a website.
