Table of Contents
Introduction
The Domain Name System (DNS) acts as the backbone of the internet, translating user-friendly domain names into computer-readable IP addresses. This system relies on various types of DNS records, each serving a crucial role in directing web traffic, managing emails, and ensuring the smooth functioning of online services. Understanding these different record types is fundamental to comprehending how information is organized and accessed across the vast landscape of the internet.
Types of DNS records with explanations
1. A record
The A record is the most important DNS record type. The “A” in A record stands for “address.” An A record shows the IP address for a specific hostname or domain.
Use of a record
The main use of A record is for IP address lookup. Using an A record, a web browser is able to load a website using the domain name. As a result, we can access websites on the internet without knowing their IP addresses.
Another use of A record is in the domain name system-based blackhole list (DNSBL). Here, the A record is used to block mail from known spam sources.
2. AAAA record
AAAA record, just like A record, point to the IP address for a domain. However, this DNS record type is different in the sense that it points to IPV6 addresses.
IPV6 is an upgrade over IPV4 as it offers more IP addresses. As a result, IPV6 solves the issue of running out of unique IP addresses. An IPV6 address looks something like the following:
Use of AAAA record
Usage of the AAAA record for DNS resolution has great potential because it uses IPV6, which is an improvement over IPV4. Also, as the internet keeps growing and we’re running out of IPV4 addresses, the potential for AAAA records is high.
AAAA records are used to resolve a domain name to the newer IPV6 protocol address.
3. CNAME record
CNAME—or, in full, “canonical name”—is a DNS record that points a domain name (an alias) to another domain. In a CNAME record, the alias doesn’t point to an IP address. And the domain name that the alias points to is the canonical name. For example, the subdomain ng.example.com can point to example.com using CNAME. Here example.com points to the actual IP address using an A record.
Use of CNAME record
A practical example for the use of CNAME records is running multiple subdomains for different purposes on the same server. For example, we can use ftp.example.com for file transfer protocol (FTP) and serve webpages via www.example.com. We can then use a CNAME record to point both subdomains to example.com. The main domain example.com then points to the server’s IP address using an A record.
It’s also possible to point a CNAME to another CNAME. However, doing so is inefficient and can lead to slow load speed and poor user experience.
4. NS record
A nameserver (NS) record specifies the authoritative DNS server for a domain. In other words, the NS record helps point to where internet applications like a web browser can find the IP address for a domain name. Usually, multiple nameservers are specified for a domain. For example, these could look like ns1.examplehostingprovider.com and ns2.examplehostingprovider.com.
Use of NS record
If you’ve purchased a web hosting service or set up a simple website, you probably received an email with nameserver details. Those nameservers, in simple terms, connect your domain name to the actual server your site is hosted on. The nameserver contains other DNS records for the domain like an A record and MX record.
5. MX record
A mail exchange (MX) record, is a DNS record type that shows where emails for a domain should be routed to. In other words, an MX record makes it possible to direct emails to a mail server.
You can have multiple MX records for a single domain name. And what this means is that you can have backup email servers.
Use of MX record
With an MX record, it’s possible to hand off emails to a dedicated email server. For example, you can decide to leave all the trouble of setting up webmail on a server you own to a specialized email provider. This comes with many benefits, including custom email clients for reading and sending emails, and improved security and spam filters. Also, you can use a service like Site24x7 to monitor and verify issues with the mail server your MX records point to.
6. SOA record
SOA stands for “start of authority.” It’s an important DNS record type that stores admin information about a domain. This information includes the email address of the admin and when the domain was last updated.
7. TXT record
TXT stands for “text,” and this record type lets the owner of a domain store text values in the DNS. Several services use this record to verify ownership of a domain.
8. PTR record
A pointer (PTR) record provides a domain name for reverse lookup. It’s the opposite of an A record as it provides the domain name linked to an IP address instead of the IP address for a domain.
9. SRV record:
Using this DNS record type, it’s possible to store the IP address and port for specific services.
Conclusion
In the intricate web of internet infrastructure, DNS records stand as the unsung heroes, silently but efficiently guiding our online interactions. From pointing users to the correct web servers to managing email routing and other essential services, each record type plays a specialized role in ensuring that the internet remains interconnected and accessible. As technology advances and the digital landscape evolves, the significance of DNS records continues to underscore their importance in maintaining the seamless functioning of our online experiences.