We get asked a lot, so here’s a breakdown of what an apex domain is - also known as domain apex, naked domain, or zone apex - what it does, when we use it, and why you might want to know this.
A domain apex is the root of a registrable domain and does not contain a subdomain part. Apex domains are also often referred to as base domains, bare domains, naked domains, root apex domains, or zone apex domains but these are all relatively interchangeable in descriptions.
The easiest way to explain what an apex domain is by example. Let’s say you purchased newgreatbrand.com. This “newgreatbrand.com” would be the “domain apex”, because it is the “root” of the hierarchy of domain names, the “base” of all things to come from this domain. The starting point of all further subdomains that will relate to this. URL’s like “www.newgreatbrand.com” are a “subdomain” of the base domain, as would “shop.newgreatbrand.com”, or any other subdomain of the domain apex newgreatbrand.com. Additionally, apex domains are often redirected to a WWW subdomain and need to be done so securely HTTP to HTTPS, thus requiring an SSL certificate so visitors don’t see security warnings in their browsers.
The difference between a domain apex and a subdomain is very important when working with urllo to set up website redirects or URL redirection. When redirecting a domain apex you typically need to use a DNS “A record” to point to urllo, whereas subdomains should use a “CNAME record”. This is due to a limitation in DNS whereby A records and MX records can not exist together on the same level of the zone hierarchy. This is all a bit nerdy, but as a general rule-of-thumb you should use a CNAME record wherever possible, and an A record if required - and it usually is required on an apex domain.
What is an A record?
The “A” in A record stands for “address”, which is what you use to point a domain apex. When it comes to a Domain Name System (DNS), an A record is one of the most fundamental types of DNS records as it points to the IP address of a specific domain. If you were to lookup the A record of newgreatbrand.com, the A record would return a specific IP address and should only show an IPv4 address. A records can map domain names to one or many IP addresses directly.
What is a CNAME record?
Canonical Name records (CNAME record) are used for all other types of domains that are not domain apexes. CNAMEs map a domain name to another domain name rather than an IP address making them more flexible. They are preferred by technical people because they are more reliable and easier to scale versus an A record. Whenever possible, urllo will direct you to use a CNAME record rather than an A record, as a CNAME record allows us to dynamically return different IP addresses on your behalf. This means you get the best possible speed, reliability and security. Though this may vary on a case by case basis.
Limitations
As explained above, DNS A records require that you have an IP address hard-coded into your application’s DNS config. This prevents your infrastructure provider from assigning a new IP address to your application on your behalf when challenges come up and could result in serious issues for your application and it’s up time. This inflexibility can be problematic in domain redirection.
A CNAME record doesn’t require a hard-coded IP address, as we’ve gone through above, and allows your infrastructure provider to manage any IPs related or associated to your domain. The limitation being that CNAME records usually can not be used to configure the root domain, and are therefore not available at the apex domain.
Hopefully this gave you a better idea of the differences and a few unique use cases for domain apexes, CNAMEs and A records. For more information get in touch with our team and we’ll be more than happy to discuss this with you further and how it relates to your website redirection process.