CNAME Flattening (ANAME Records)

When DNS was first invented, the idea of how our modern-day systems work was inconceivable. It is because of this that some RFC rules restrict DNS record usage in ways that can be inconvenient in today’s digital world. One such example is how CNAME records work. Of course, where there is a will, there’s a way. We developed a way of circumventing CNAME restrictions without breaking the DNS—ANAME record technology (also known as CNAME flattening). 

What is a CNAME Record? 

A CNAME record, or canonical name record, is a DNS record that points a fully qualified domain name (FQDN) to a hostname. For example, the subdomain www is an alias of the root or naked domain. So, if users are visiting www.constellix.com, they are actually being referred to constellix.com. 

How Do CNAME Records Work?

As mentioned above, CNAME records act as an alias. They map parts of a domain to an external FQDN. This can be helpful as only the A record of a domain requires updating if the domain’s host/IP address changes. The CNAME records will follow suit because they ultimately resolve to the address of the A record. Does this mean if you have the subdomain “about.constellix.com” and the CNAME is pointed to “constellix.com” that a user will be directed to the home page of your website? No. Even though the client is connected to the IP address, the web server knows to deliver the user to the “about” page. 

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Common Use Cases For CNAME Records

The most common use cases for configuring CNAME records is to map multiple websites to the main website of a company or to point a domain to content delivery networks (CDNs) or other cloud services, such as a DDoS Protection service. They are also used for pointing network hostnames to the root of a domain and for registering the same domain in multiple countries.  

CNAME vs A Records

The main difference between CNAME and A records is that A records can be used at the root of the domain. And unlike CNAME records, that point to a hostname, A records must map to an IP address. Another difference is that CNAME records require double lookups, as they require resolvers to acquire the CNAME record and then find the corresponding IP address.

What is CNAME Flattening/ANAME Records?

An ANAME record is a hybrid of an A record and a CNAME record. It has all the “powers” of both, but without the limitations. When you create an ANAME record, it functions just as a CNAME record but it can be pointed to the root of a domain. Talking about a satisfying rule-breaker! 

How ANAME Records and CNAME Flattening Work

What you are essentially doing when configuring an ANAME record (or flattening a CNAME) is making a dynamic A record. Cool, right? The way this works at Constellix is that we perform a real-time lookup (dig) on the FQDN when the ANAME record is requested. This ensures we have the most up-to-date IP address. While this results in a double DNS lookup, our  ANAME technology actually reduces resolution times—and everyone wants that!

ANAME Record Wrap Up

In a nutshell, ANAME records provide ultimate flexibility by allowing you to have a CNAME record at the root of your domain. You can have multiple ANAME records and can combine them with each other or combine them with A records. Because ANAME records skip extra hostname resolution, they are also faster than CNAME records too. Whether you use multi-CDN, want to register your domain in several countries, or point multiple company sites to your main website, ANAME is an excellent solution for any organization.