5 Different Types of DNS Servers

DNS servers play an essential part in the internet’s functioning. They translate human-readable domain names to IP addresses understood by computers. Various types of DNS servers are available, each serving its specific purpose and offering special features. Some DNS servers are better suited for small businesses while others are tailored towards larger enterprises. Certain servers prioritize security over speed. Understanding the types of DNS servers and their uses is vital to selecting the optimal one for your organization’s needs. From increasing security, speed and reliability of online presence, there’s sure to be one out there that fits right. Here are 5 different types of DNS servers.

What Is a DNS Server?

DNS servers serve as the internet directory, translating domain names to IP addresses so computers can communicate. When typing website addresses into your browser, for instance, they match up with their respective IP addresses and direct your device directly to them. These servers maintain a vast database of domain names and their corresponding IP addresses, serving as an internet’s phonebook. In fact, every time you access a website or send an email, a DNS server helps match its domain name to its IP address.

DNS servers operate under a hierarchical structure, with each level taking on different roles in domain name resolution. Root DNS servers oversee top-level domains like .com or .org while top-level domain servers direct requests directly to authoritative DNS servers for that domain.

An efficient DNS server is essential to providing an enjoyable internet experience. A slow or unreliable DNS server could slow page loads times or prevent accessing certain websites altogether.

Forwarding Servers

Forwarding servers (or DNS forwarders) serve as intermediary servers between clients and authoritative DNS servers. They receive DNS queries from clients before forwarding them on to their appropriate authoritative DNS servers, which then respond to them and send the response back out via forwarding servers to clients.

Forwarding servers are effective tools when an organization seeks to centralize their DNS queries. One can centralize all DNS queries for different parts of their network rather than having separate DNS servers dedicated to specific parts. This makes the management of all its queries much simpler and easier overall.

Forwarding servers improve performance, offering an additional advantage. A forwarding server caches DNS responses. Therefore, if clients make multiple identical queries to it, then its cached responses can respond without forwarding to an authoritative server, speeding up resolution time and improving overall network performance.

Be wary of confusing forwarding servers with the authoritative servers of domains they forward. These serve only as proxy proxies that forward queries directly to their authoritative counterparts for responses. Therefore, contact the authoritative server directly to make updates, not its forwarding counterpart.

Caching-Only Servers

Caching-only servers are a special type of DNS server that only store information regarding recently resolved queries rather than providing authoritative domain records and zone files. In short, they enhance client DNS resolution performance. When clients inquire about domains, these caching-only servers check their cache to see if they contain relevant data. If they do, they return this to them instead of querying authoritative DNS servers. This significantly decreases resolution time and improves network performance overall.

Small to mid-sized networks that do not need full DNS services should use caching-only servers for optimal performance, acting as forwarders for other servers. However, never rely on caching-only servers as authoritative sources of domain information. They provide only cached information that may be out-of-date or inaccurate. Therefore, one should not use them in situations where accurate DNS information is critical, such as in enterprise environments.

Secondary Servers

Secondary servers are a type of DNS server designed to act as backup for primary servers. They keep a copy of the DNS database in case one or both fail or become unavailable. They receive updates via “zone transfer,” ensuring they contain identical information to their primary counterparts.

Whenever the primary server goes offline, its secondary counterpart will take over responding to DNS queries from clients and ensure the service continues functioning regardless of issues with the primary one. DNS plays an important role in online communication because it translates domain names to IP addresses used by computers for finding each other online.

Secondary servers are usually placed at different geographical locations from the primary server to add extra redundancy. It ensures that DNS services continue operating even if issues arise in one region. Secondary servers also help distribute the load of handling DNS queries across, improving the performance of DNS services overall.

Note that secondary servers typically do not respond directly to DNS queries unless their primary counterparts are unavailable. In normal operation, only the primary server handles any DNS inquiries pertaining to DNS information. This ensures that its authoritative status cannot be challenged.

Primary (Master) Servers

Primary Servers are the cornerstone of DNS services. They store the original domain and IP address details when first registered with an ISP. They store this initial information permanently when first registered. Then, when new domains register, their information is saved on such primary servers. Further, any time changes to a domain’s information occur, they should always be made on its primary server to ensure all DNS servers have access to the latest details about its domain. Once this server has sent out updates, secondary servers provide backup should it become necessary. For example, in case the primary one goes offline.

Primary servers play an essential role in ensuring the proper functioning of the Internet. Without them, DNS servers would not have access to all the required information for translating domain names to IP addresses and therefore the internet would cease functioning correctly.

As part of an effective domain hosting solution, having at least two primary servers is crucial for reliability. Should one go down unexpectedly, its backup can step in seamlessly, keeping user information accessible at all times.

Root Servers

Root servers are the cornerstone of any domain name system (DNS). As it’s at the top level of the hierarchical structure, these DNS servers play an indispensable role in resolving domain names to IP addresses.

Root servers store information about top-level domains such as .com , .org and .gov. When someone makes an internet request to access a website, their query first goes to a root server for processing before passing to an appropriate top-level domain server, which ultimately connects it with the authoritative name server of that particular domain. Root servers do not store all information regarding domains. They contain pointers to authoritative name servers for each top-level domain. This creates a more resilient and scalable distributed system.

Various organizations maintain thirteen global root servers. To increase reliability and mitigate single-point-of-failure risks, they are spread out among multiple locations to prevent any single point of failure from becoming too powerful for users to handle.