The digital universe is a vast, interconnected web of computers and servers, each relying on complex protocols to communicate with one another. Among these protocols is the Domain Name System (DNS), often referred to as the ‘phonebook of the Internet.’ But what exactly is a DNS server, and how does it function? Find out everything you need to know about DNS servers in this post.
What is a DNS server?
A DNS server is essentially a computer server that contains a database of public IP addresses and their associated domain names. It operates on the DNS protocol, which is a standard set of rules for exchanging data on the Internet and other networks, such as private Local Area Networks (LANs). The primary role of a DNS server is to translate human-friendly domain names (like www.google.com) into machine-friendly IP addresses (for instance, 192.0.2.44).
Purpose of a DNS server
The primary purpose of a DNS server is to simplify the process of accessing information online. DNS server configuration helps enable smooth connectivity to the internet. Without DNS servers, we would have to remember a long string of numbers (IP addresses) for each website we want to visit – quite an inconvenient task! DNS servers take up this responsibility by mapping domain names to their corresponding IP addresses, allowing users to connect to websites using easy-to-remember names rather than numerical addresses.
How a DNS server resolves a query
When you type a web address into your browser, a DNS query is initiated. This process involves several stages:
- Recursive query – Your device sends a recursive query to the DNS resolver, usually operated by your Internet Service Provider (ISP).
- Root server query – If the DNS resolver doesn’t have the required information in its cache, it forwards the query to a root server. The root server responds with a pointer to the Top-Level Domain (TLD) server (like .com or .org).
- TLD server query – The DNS resolver then sends a query to the TLD server, which responds with a pointer to the authoritative DNS server for that specific domain.
- Authoritative DNS server query – Finally, the DNS resolver sends a query to the authoritative DNS server, which responds with the IP address of the domain. The DNS resolver then returns this IP address to your device.
Security considerations for DNS servers
Despite their crucial role in Internet functionality, DNS servers can pose certain security risks. For instance, DNS spoofing or cache poisoning is an attack where the attacker introduces corrupt DNS data into the DNS resolver’s cache, causing the resolver to return an incorrect IP address and potentially redirect users to malicious websites.
To counter these threats, DNSSEC (Domain Name System Security Extensions) was introduced. DNSSEC adds digital signatures to DNS data to validate the data’s source and integrity.
The essential role of DNS servers in IT
DNS servers play a pivotal role in how the Internet operates, translating human-friendly domain names into machine-readable IP addresses. While they do have some security concerns, measures like DNSSEC are in place to ensure secure, trustworthy data transmission.