What is DNS and How Does It Work: A Comprehensive Guide on Domain Name System
Created on 21 April, 2023 • 224 views • 16 minutes read
Users connect to websites using domain names instead of IP addresses with the help of DNS. Know all about DNS working.
You must have wondered sometime how the Internet works. And have you thought about how you magically access all sorts of information and dog videos with just a few clicks?
There's a hidden hero behind the scenes, making all this possible: the Domain Name System, or DNS for short.
Simply put, DNS is like the phone book of the Internet. Just like you use a phone book to find someone's phone number, your device uses DNS to find the IP address of the website that you're trying to visit.
Let’s say you want to check out the latest funny memes on 9GAG. To do this, you input "9gag.com" in your browser's address bar and hit search. Next, your device sends a request to a DNS server to ask for the IP address of 9gag.com. The DNS server looks up its records and finds the corresponding IP address, something like 151.101.129.67. Once the IP address is found, your device can connect to the website and fetch all those memes to enjoy.
But how exactly does DNS work, and what happens if something goes wrong?
In this blog post, we will answer all the queries about DNS and its working. You'll understand how DNS lookup works, what the different types of DNS lookup are, and how to troubleshoot common DNS issues.
Let's get started!
What is DNS?
The acronym DNS is the abbreviation of Domain Name System.
DNS is the Internet equivalent of a phone book. The DNS maintains a domain name directory and translates these into Internet Protocol (IP) addresses. The way DNS works is like turning on the contacts section of your smartphone. Suppose, you want your friend John's number? You just type the name you want to find and your phone looks it up for you.
The information received from all the domain name servers on the Internet is stored in the Domain Registry operators. Hosting companies and Internet Service Providers are constantly in contact with Domain Registry operators to obtain up-to-date DNS information.
What is the primary function of DNS?
This DNS system was created so people would not have to remember a number to go to a website. Instead of remembering a number, they could remember a much simpler name.
Thus, the primary function of the DNS is name resolution. It is an architecture that assigns names to IP addresses so that when a user tries to access another computer on a network, it directs them there.
When you type a web address, for example, www.superwebtoolz.com, your ISP (Internet Service Provider) queries DNS, looks up the domain name, translates it into a machine-friendly IP address (for example, 162.0.232.37 is the IP for www. Superwebtoolz.com) and directs your Internet connection to the correct website.
This system is the current basis for the operation of the Internet. It is responsible for translating the web domain names to the IP of the computer where the page you are looking for on the Internet is hosted.
Let's understand it much better with an example.
How does DNS work?
The web pages are hosted on computers called web page servers or hosting. A specific web page will be hosted on a specific server.
This web page is identified with a unique number within the Internet, a very long number that is difficult to remember.
That number is the number of the server (computer) where the web page is hosted.
For example, 162.0.232.37 is the IP number (computer where the page www.superwebtoolz.com is hosted). If you want to enter the page, you should remember this number, access it through the browser with that number, go to the computer (webserver) where it is the web, and download it to view it in the browser.
Wouldn't it be easier to remember the website's domain name instead of that long number? Well, now is when the DNS comes into play.
When you type www.superwebtoolz.com in your browser or any other name of a website, your computer, through the browser, sends this domain name to a computer called a DNS server owned by your Internet provider (Vodafone, Orange, etc.).
This DNS server "translates" the domain name (www. superwebtoolz.com) that you send to it to the IP address of the server where the web page is hosted, sending your request to the specific computer where the page is hosted.
In this case, remember that www.superwebtoolz.com was hosted on a server called 162.0.232.37.
Now your computer connects with the IP address the DNS server indicated, and your browser shows the content of the page www.superwebtoolz.com.
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One of the interesting things about DNS is that it's hierarchical.
At the top of the hierarchy are the root servers. Root servers contain information about top-level domains like .com, .org, and .net.
Below the root servers are the top-level domain (TLD) servers. TLD servers contain information about specific TLDs like .com or .org.
Below the TLD servers are the authoritative DNS servers, which store information about individual domain names. For example, if you want to look up the IP address for google.com, your request would finally reach Google's authoritative DNS server, which has the needed information.
Thus, DNS plays an important role in the functioning of the Internet. Without DNS, we would have to remember the IP addresses of every website we want to visit. Wouldn’t that be a daunting task? DNS makes it easy for us to use domain names instead of long IP addresses and further ensures that we can access websites from anywhere in the world.
Types of DNS Lookup
DNS lookup is when a device looks up the IP address associated with a domain name.
There are two main types of DNS lookup: recursive and iterative.
Recursive lookup is the most common type of DNS lookup. In a Recursive look-up, the device sends a request to a DNS server, which then sends requests to other DNS servers until it finds the IP address associated with the domain name. This process continues until the IP address is found and returned to the device.
On the other hand, Iterative lookup involves the DNS server sending a partial response to the device, which then sends requests to other DNS servers until the IP address is found. This type of lookup is less common but useful in specific scenarios.
Another type of DNS lookup is reverse DNS lookup. This type of DNS lookup involves looking up a domain name based on an IP address. This is often used for security purposes, such as identifying potential threats or checking the validity of email senders.
In addition to these types of lookups, tools like nslookup can be used to perform DNS lookups and troubleshoot any issues manually.
In general, DNS lookup is an important aspect of the way that the Internet operates and allows us to connect to the sites and services that we use every day without difficulty. Knowing the various types of lookups as well as how they function can help you in resolving any connection issues and help you appreciate the technology behind the Internet.
The DNS Lookup Process
The DNS lookup process involves a series of steps that occur behind the scenes every time you access a website or application on the Internet.
Let's look at the process with an example.
Say we are trying to get access to the www.superwebtoolz.com website.
Step 1: Information Request
Type the domain name (www.superwebtoolz.com) into your web browser, and it will query the DNS to find the answer as to where it is located. The DNS resolver is like your go-between.
Step 2: Root Name Servers
The DNS resolver asks the root nameserver for the IP address. They don't have the answer to your question but know where to find it. The response from the root name servers is the address of the Top-Level Domain Name Servers (TLD or Top Level Domain).
In the case of www.superwebtoolz.com, they are the name servers .COM.
Step 3: First Level Domain Name Servers (TLD or Top Level Domain).
The DNS resolver now asks the TLD nameserver for the IP address of the domain name. The TLD nameserver responds with the address of the authoritative nameserver for the domain name.
In our example, the nameserver.COM addresses the authorized name servers of superwebtoolz.com.
Step 4: Authoritative DNS Servers
Authoritative DNS servers keep DNS records of domain names needed for DNS resolution. Ideally, these records are maintained in a zone file by the domain owner or the technical administrator responsible for managing the functional behavior of the domain name. There are different records within a zone file; for example, the server's IP address where the website is hosted is represented by an Address Record, commonly called an 'A' record.
Step 5: Retrieve the Registry
The recursive server gets the 'A' record for the website from the authoritative nameservers and stores it in its local cache. If someone else is looking for the same website, the information will already be there, and you won't have to go through the whole process.
Step 6: Access the Website
The recursive server sends the 'A' record to your computer. The PC saves this record, reads the IP, and passes the information to your browser; which then connects to the web server, and you will see www.superwebtoolz.com.
Although it is a long and complicated process, it is instantaneous; it only takes microseconds for the entire DNS resolution process.
With this system, website users need to know your domain name only. The IP address of the individual server your site is hosted on is irrelevant to them. If changes are made to your domain name or website, the DNS will also be updated to point to your IP address on the new server. Visitors still access your website using your domain name, even when your IP address has changed. This type of flexibility is the reason why the Internet is so powerful.
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Troubleshooting DNS Lookup Issues
If you've ever tried to load a webpage, it just wouldn't come up, you might have encountered a problem with DNS lookup. Although it's a crucial part of the Internet, DNS lookup isn't always perfect. Sometimes there can be issues that prevent it from working correctly.
Some common issues during DNS lookup include slow loading times, errors in the DNS configuration, or problems with the DNS server itself. And the frustrating part of these problems is that they are not easy to diagnose.
If you encounter a problem with DNS lookup, you can try a few things to troubleshoot the issue. One standard solution is to flush the DNS cache on your device. This will clear out any stored DNS data and force your device to do a fresh DNS lookup.
An alternative is to switch the DNS server your device is currently using. Sometimes the default DNS server provided by your internet service provider can be slow or unreliable, so switching to a different server can help resolve DNS lookup issues.
If you're still having trouble, you might want to consider looking into the DNS configuration of your device or router. Make sure your DNS configuration is correct and that there aren't any typos or errors in the DNS configuration.
In certain cases, there may be a problem with the DNS servers itself. Say you're on a public DNS server (such as Google DNS or OpenDNS), you can examine the status of your server to determine whether there are any reported issues. You might need to reach your network administrator to get assistance in the event that you're using a Private DNS Server.
In the end, troubleshooting DNS issues with lookups can be difficult. However, with a little patience & knowledge about DNS, it is possible to get things working again. And knowledge of how DNS lookup works will make you better equipped to tackle any issues that may arise.
Use cases for online DNS lookup
In many situations, online nslookup can be a helpful tool. For instance, you may be looking to determine if you've configured the DNS records for your domain properly.
Once you have changed DNS records It takes a while to propagate throughout the DNS system. This is because DNS servers cache records to speed up DNS resolution. Thus, whenever you change DNS records, you can use DNS lookup to check whether they have propagated yet by doing a DNS lookup.
Conclusion:
Thus, DNS is an essential element of the Internet that lets users quickly access websites via domain names, not IP addresses. DNS search is the method of translating a domain's name to an IP, and it plays an important role in loading websites.
Understanding DNS is crucial for anyone who uses the Internet. It helps you troubleshoot issues, improve website load times, and protect yourself from cyber threats. By using DNS, we can easily access the vast amount of information available on the Internet.
Next time you're on the Internet, take some time to appreciate the intricate system of DNS search that makes it possible.
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Common FAQs about DNS (Domain Name System):
1. What is DNS?
A Domain Name System (DNS) is a computer that translates human-readable website names (such as superwebtoolz.com) into IP addresses (like 162.0.232.37) that are used to locate and identify computers.
2. Why do we need DNS?
We need DNS because humans find it easier to remember domain names like google.com than IP addresses like 172.217.12.206.
3. How does DNS work?
DNS works by translating domain names into IP addresses. When you enter a domain name into your web browser, the browser requests a DNS resolver to look up the IP address associated with that domain name. The resolver then queries one or more DNS servers to get the IP address. The DNS server then responds to the resolver with the IP address, which the resolver sends back to the web browser. The web browser can then connect to the website with that IP address.
4. What is an IP address?
An IP address is a code that will identify each user who is browsing any network, and it is the Internet's way of knowing who is who, be it a domain or a computer. A device will not be able to establish communications with anyone if it does not have one of these addresses.
The purpose of an IP address is to uniquely identify and locate each device on an internal or external network. It is a number that identifies an interface, which can be both a computer and a smartphone or any other electronic device that connects to the Internet.
5. What is a domain name?
A domain name is a unique name that identifies a website on the Internet.
A domain name is a personalized and unique address for your web page. It consists of two parts: the name and the extension or TLD (top-level domain). For example, “superwebtools.com” contains the name “superwebtools” and the extension or TLD “.com”.
6. What is a TLD?
A Top-Level Domain (TLD) is the final extension separated by a period of the domain name. The TLD represents the highest category of domains. For example, for the domain www.superwebtoolz.com, the top-level domain is ".com".
There are two types of top-level domains:
- Country-specific top-level domains (for example .es, .uk, or .fr).
- Generic Top-Level Domains (gTLDs) (for example .net., .com, .org, .info).
Country-specific TLD granting rules depend on each country, for example, for the French TLD ".fr" it is necessary for the domain owner to have their home or business located in France.
7. What is an SLD?
A second-level domain is a specific part of a website, page domain name, or URL address that complements a top-level domain. One of the easiest ways to define a second-level domain is that it consists of that part of the domain name to the left of ".com" or some other similar extension, which is called a top-level domain.
Although SLD falls under the TLD in the domain hierarchy, the second-level domain is no less important than the extension. In fact, the opposite is happening more and more frequently: the domain name is increasingly important both for users and for search engine positioning since it can better describe the content of a web page and contain keywords.
Let’s take an example domain- www.superwebtoolz.com. Here, the second level domain is “superwebtoolz”.
There are even country-specific second-level domains, as the examples in the table below demonstrate, with the TLD . uk.
8. What is a DNS resolver?
A Domain Name System (DNS) resolver, more commonly known as a "DNS lookup" tool, resolves (translates) an individual hostname to an IP address. This type of resolver command helps discover how web services are hosted, how a domain name is supported, and how various hardware devices correspond to individual servers and providers or their client companies. Your computer or device uses a DNS resolver to connect to websites and other online services.
9. What is a DNS server?
A DNS server is a computer or device that stores DNS records and responds to DNS queries from DNS resolvers. DNS servers are responsible for translating domain names into IP addresses and directing traffic on the Internet.
10. What is a DNS record?
A DNS record is information stored on a DNS server and associates a domain name with an IP address. There are many types of DNS records, such as ‘A’ records, ‘MX’ records, ‘CNAME’ records, and others.
11. What is an A record?
An A record is a DNS record that maps a domain name to an IP address. It is the most common DNS record type and is used to direct traffic to a specific IP address.
12. What is a CNAME record?
A CNAME record is a DNS record that maps one domain name to another. It is often used to create aliases or alternate names for existing domain names.
13. What is an MX record?
An MX record is a DNS record that specifies the mail server responsible for handling email for a particular domain name. It is used to direct incoming emails to the correct email server.
14. What is DNS caching?
DNS caching is the process of temporarily storing DNS records on a device or network. This can improve the speed and efficiency of DNS lookups by reducing the need to query DNS servers for the same information repeatedly.
15. What is DNS propagation?
DNS propagation is the time it takes for DNS changes (such as adding or modifying DNS records) to be distributed and updated across the entire DNS system. It can take anywhere from a few minutes to several days for DNS changes to propagate fully.
16. What is DNS propagation?
DNS propagation is the time it takes for the changes made to the DNS records to be propagated throughout the Internet.
17. How long does DNS propagation take?
DNS propagation can take anywhere from a few hours to 48 hours, depending on various factors, such as the TTL (Time To Live) value set in the DNS records.
18. What is DNS spoofing?
DNS spoofing is a type of cyber attack where the attacker redirects the user to a fake website by modifying the DNS records.
19. How can I check my DNS records?
You can use various online tools such as superwebsitetoolz.com, dig, or online DNS lookup tools to check your DNS records.