A Record vs CNAME - Differences Between A and CNAME Records

A Record vs CNAME – The Domain Name System or DNS connects our web browsers to websites. It acts like the internet phonebook servers use to map domains to their corresponding IP addresses.

However, understanding DNS and its components can be daunting, especially regarding resource records. From SOA records in the DNS and PTR records to TXT records, MX records, and NS records, DNS components are tricky.

Still, to mitigate DNS spoofing and ensure your website’s peak performance, it’s a good idea to understand the fundamentals.

Two DNS records that are often confused are the DNS A record and CNAME record.

In our DNS A record vs. CNAME record blog post, we discuss each DNS record and how it works. Then we’ll move to the differences between them. Let’s get started!

What Are CNAME Records?

CNAME stands for Canonical Name, and a CNAME Record is a type of DNS record that links one domain name to another. In simple terms, it creates an alias for a domain, so you can access the same website using different domain names.

A CNAME record is a DNS record that provides an association for alias domains and subdomains to the main, parent domain. The “C” stands for “canonical,” as this DNS record connects subdomains to the canonical name-domain or the records delivered for another DNS hostname.

Let’s look at how this looks. When you set up an A record for example.com you associate it with the 103.14.89.32 IP address. However, that doesn’t include domain aliases, such as www.example.com. That’s right, even adding a www before the domain name won’t lead you to the correct website unless a CNAME record exists to provide instructions that those two domains are to result in the same page.

Keep in mind, however, that a CNAME record creates a connection between a subdomain and a parent domain also, which means that it doesn’t always result in the same page popping up. For instance, when you have subdomains for a website, such as blog.example.com or mail.example.com, you still need to create CNAME records that link these subdomains to the parent domain.

Of course, this doesn’t mean that when users try to access a subdomain of that domain, they end up on the home page, i.e. the same page as the parent domain. Rather, users are directed to the appropriate files for that subdomain, such as the blog page or the mail page rather than the home page.

CNAME records are quite useful when webmasters change the IP address of their website. Rather than having to change A records for each subdomain, they only have to change the A record for the parent website.

Uses of CNAME Records

CNAME Records are essential for managing your website’s domain names. They create aliases for your primary domain, allowing you to point multiple domain names to the same destination. Let’s examine their different purposes and how they can benefit your website management:

Managing multiple domain names: CNAME Records make it easy to direct multiple domain names to the same server, simplifying the process of maintaining your website’s accessibility
Creating memorable domain names: CNAME Records can be used to create easy-to-remember domain names for different sections of your website
Streamlining server migrations: With CNAME Records, updating the IP address in one place reflects the change across all aliases, making server migrations simpler
Reducing manual IP address updates: By using CNAME Records, you can save time and effort by minimizing the need for individual IP address updates

What Are A Records?

The purpose of DNS A record is to help you land the desired website without entering the IP address. It contains records of IP addresses corresponding to particular websites; thus, A stands for ‘address.’ Without an A record, you won’t be able to reach a website through its domain name.

Whenever you type any domain name into your browser’s address bar, the responsible server returns the IP address for the domain, which is located in the zone files. This lets you navigate a website.

For instance, you can enter the domain name ‘mydomain’ into your browser’s address bar, and the DNS A record digs out the IP address. Note that A records only work with IPv4 addresses and not IPv6. You would require an AAAA record for IPv6. You can check your A records using an A record lookup tool.

Uses of A Records

A Records are essential in the DNS as they establish direct connections between domain names and IP addresses. Now, let’s take a closer look at their various purposes:

Directly linking domain names to IP addresses: A Records provide a clear and direct path between your domain name and the server hosting your website, ensuring a smooth user experience
Simplifying website management: By using A Records, you can easily manage the IP addresses associated with your domain names, making it more convenient to maintain and update your website
Supporting different types of records: A Records work alongside other DNS records, such as CNAME and MX records, to provide a comprehensive and flexible system for managing your website’s accessibility

What’s the Difference Between A Record vs CNAME?

CNAME and A records are often confused with each other, but there are differences. First, an A record can only connect the primary parent domain to the corresponding IP address. On the other hand, CNAME records link the parent domain to its alias or subdomains.

In other words, CNAME records can point to other CNAME records or A records but A records can only point to the IP address of a domain. Moreover, a parent domain can only have an A record, not a CNAME record

Distinguishing A and CNAME Records (A Record vs CNAME)

Destination Control: A records provide a direct route, pointing directly to an IP address, whereas CNAME records point to another domain name
Flexibility: CNAME records outshine A records in flexibility. Changes need to be made only once at the final A record destination, and all associated CNAME records will automatically follow suit
Restrictions: CNAME records cannot coexist with other records for the same domain, and cannot be used for root (apex) domains (if no CNAME Flattening). A records do not have these restrictions
Performance: DNS lookups for A records are generally slightly faster because they involve a single direct lookup. A CNAME record requires an additional lookup to resolve the final A record
Use Case: A records are used when you want to point a domain or subdomain to a specific IP address. CNAME records are used when you want to alias one domain or subdomain to another

Comparing A Record vs CNAME: Pros and Cons

Choosing between A Records and CNAME Records involves weighing their pros and cons. To better understand them, take a look at these advantages and disadvantages:

A Records

Pros:

Fast and efficient, directly connecting domain names to server IP addresses
Greater control and flexibility over DNS records
Useful when creating specific DNS records for mail servers

Cons:

Difficult to manage when IP addresses change frequently
Not suitable for load balancing or disaster recovery
Can result in data duplication if multiple A Records are created for the same IP address

CNAME Records