What is a DNS Server?

With 367.3 million domain names reported to have been registered in the second quarter of 2021 alone, we couldn’t possibly remember all of the IP addresses for the websites that we want to visit without having a directory of sorts. A DNS server solves this issue as it is like the digital phone book of the internet. It holds all the IP addresses to the registered domains and allows us to locate them by simply entering the website name or the fully qualified domain name (FQDN). 

What is DNS?

DNS stands for domain name system. It is the way we are able to connect to the web as we know it today. DNS is the process of mapping an FQDN to its IP address. To be able to grasp how this works in such a short amount of time (typically milliseconds), it’s important to understand the process. 

What is a DNS Query?

A DNS query (request) is a prompt for information sent from a user's computer (DNS client) to a DNS server.When you enter a website in your browser, this initiates a query. It goes through a series of servers before the site displays on your screen. 

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What are different types of DNS servers?

1. Recursive server

The query’s first stop is the recursive server. This is the resolving nameserver that is configured for your operating system (OS). It performs all the lookups your OS requests. While most people have one configured, you can have more than one on a single OS for redundancy. 

Whenever someone accesses a website, the recursive server stores the DNS request in cache to use for others who share the same recursive nameserver that performs this search. This helps to improve the experience for other users that connect to the same recursive server. The DNS query is stored in the cache on this server until it is cleared out automatically through a time out, which is specified by the time to live (TTL). TTL is configured when the domain is set up to establish how long the nameservers will hold on to DNS record information. The recursive server can either immediately resolve the search by providing the information it has stored in its cache or contact a series of authoritative servers to obtain all the information it needs to locate the FQDN being searched.

The recursive nameserver communicates with the root, TLD, and authoritative DNS nameservers to locate various levels of an FQDN in order to find its corresponding IP address, reading it from right to left.

2. Root Nameservers ‍

The root server locates the website’s root of the internet’s namespace. These nameservers are in charge of the “.” of the world’s DNS. When you type in a website in your browser, there is actually a dot at the end. It represents the root of the DNS space. FQDNs end with a dot, whether you see it or not. If you type in “constellix.com,” this is a small shortcut to what your browser is actually looking for, which is “constellix.com.” (note the dot at the end). 

The root server will identify the the root of the FQDN and tells the recursive server where to find the appropriate TLD nameserver for the next step. 

3. TLD Nameservers

‍The next server the recursive will visit is the top-level domain nameserver (TLD) These servers store information for all of the domain names with the same domain extension, such as .com, .net, .org, .edu, and several others. Think of it as a domain’s last name. All the information for the FQDNs with the same “last name” is stored on that particular TLD nameserver. In other words, all of the FQDNs with a .com extension are stored on COM TLD nameservers, .net are on NET TLD nameservers, and so on. The TLD nameserver then tells the recursive server which DNS server is authoritative for the website being queried. 

Once the recursive server knows where to find the authoritative nameserver, it then queries the authoritative nameserver to obtain the final answer (IP address) it needs to return to the client.

4. Authoritative Nameservers ‍

The authoritative nameserver, is the one that hosts the domain’s DNS service. It is the final authoritative device that returns the IP address of the searched domain to the recursive server. 

After the recursive server consults all of the authoritative servers to obtain the information it needs, it then returns the IP address to the client that requested the query. At this point, the client will reach out to the web servers for the data it needs to start rendering the page. It’s a seemingly laborious journey, so suffice it to say that without DNS, the internet would be a completely different experience. 

What are different types of DNS servers?

DNS Server Definition

All of this DNS action takes place in physical locations. DNS nameservers are strategically positioned around the globe to provide an optimal experience for end users. Speed is of utmost importance when browsing the internet. Well-designed DNS infrastructures serve the content with this key factor as a priority.  

DNS Server Speed and Reliability

There are many strategies by which providers obtain competitive speeds. 

DNS Peering

Peering is an important approach because it allows DNS providers to directly connect with as many networks as possible. This removes the risks of route leaks, inefficient routing, and poor speeds. 

Points of Presence (PoP)

Deploying various points of presence (PoPs) also lends a hand to increased speeds. Regional analysis is typically done to find the best location to enable healthy and fast connections. PoPs help bring the content closer to the user by providing DNS at the edge.

DNS Infrastructure

Another way DNS providers improve speeds and offer healthier connections is by investing in their own infrastructure. DNS hosts that own their own infrastructure including the routers, switches, and nameservers enable them to fully use their servers for the DNS. This ensures that those resources are not being shared by other applications that are not for the benefit of their customers. It gives them more security, capacity, stability, and reliability to be the sole user of the network.

For example, in order for Constellix to offer our industry-leading 100% uptime, we are powered by the same network that runs our sister company DNS Made Easy. It’s a standalone network that is optimized for DNS and run by our parent company Tiggee LLC (AS16652).

DNS Server: How are they used?

To access a website, there is a series of DNS servers that the query goes through to obtain the IP address. All of this takes place in DNS nameservers that are scattered across the globe to help provide all end users with the best possible speeds and healthy resources. There are also different levels of DNS. There is, what many in the industry refer to as, “dumb” DNS, which is traditional DNS that simply retrieves the IP address that belongs to the FQDN being queried. Then, we have advanced DNS that answers DNS queries differently based upon a variable of information including location, network, performance of the server, time of day, and even business calculations. Now that you know what goes on in the background, the next time you search for a website it will surely amaze you just how far we’ve come. 

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Here are some other related resources:

DNS Server Not Responding: Easy Fixes

What is Time to Live (TTL)?

What is Website Caching and Why is it so Important