In the realm of internet connectivity and website access, Domain Name System (DNS) is a cornerstone. It’s a pivotal system that helps computers understand where to go and how to get there when you type in a web address. However, for those not deeply immersed in IT or web infrastructure, the terms and concepts related to DNS can feel daunting.
In this blog post, we’ll demystify the world of DNS by explaining 7 common terms you might encounter and what they mean.
1. Domain Name
A domain name is essentially the human-friendly version of a website’s IP address. Instead of remembering a sequence of numbers, we remember ‘google.com’ or ‘wikipedia.org’. Every domain name corresponds to an IP address, and it’s the DNS’s job to map these names to their appropriate addresses.
2. IP Address
IP (Internet Protocol) Address is a unique string of numbers (and sometimes characters in the case of IPv6) separated by periods that identifies each computer using the Internet Protocol to communicate over a network. It’s like a home address for your computer on the internet. There are two versions of IP addresses currently in use: IPv4 (e.g., 192.168.0.1) and IPv6 (e.g., 1200:0000:AB00:1234:0000:2552:7777:1313).
A nameserver is a server that manages the DNS for a domain name. It answers queries about the domain, directing users to the correct IP address when they type in or click on a specific URL. When you purchase a domain, you’ll typically specify the nameservers that know how to resolve your domain, often provided by your hosting company.
4. DNS Record
DNS records are instructions stored on a nameserver that give directions about where to send a user when they request a particular domain or subdomain. There are several types of DNS records, including:
- A Record: Directs a domain or subdomain to an IP address.
- CNAME Record: Redirects one domain or subdomain to another.
- MX Record: Specifies the mail servers used for a domain.
- And several others.
5. TTL (Time To Live)
TTL is a value in a DNS record that indicates the amount of time the record is considered valid. After the specified time, servers will check again for the latest version of the DNS record. It’s a mechanism to ensure that changes to DNS settings propagate throughout the internet in a controlled manner.
6. Zone File
A zone file is a text-based representation of a DNS zone. A DNS zone is a portion of the DNS namespace that is managed by a specific organization or individual. The zone file contains mappings between domain names and IP addresses and other resources, organized in the form of text records.
7. Resolver (DNS Resolver)
A DNS resolver is a server that converts domain names into IP addresses. When you enter a URL into your web browser, it’s a resolver that queries the nameserver associated with that domain, retrieves the correct IP address, and then returns it to your browser to access the site.
8. Bonus DNS term: Secondary DNS (Backup DNS)
Secondary DNS is an additional layer of DNS server configuration running in tandem with your primary DNS. It acts as a backup system. If the primary DNS fails (due to DDoS attacks, server issues, or other reasons), the secondary DNS ensures uninterrupted domain resolution. This redundancy is critical for high-availability websites and applications where even short downtimes can result in significant revenue losses or damaged reputations.
DNS is a fundamental part of how the internet functions, ensuring we can access websites using easy-to-remember domain names rather than strings of numbers. By understanding these common terms, you can have a clearer insight into the processes occurring behind the scenes every time you visit a website or send an email. The next time you’re tweaking your website settings or discussing domain matters, you’ll be well-equipped with the foundational knowledge of DNS terminology.