Subnet Mask Cheat SheetRecords Cheat SheetGeoDNS ExplainedFree Network TroubleshooterKnowledge BasePricing CalculatorLive CDN PerformanceVideo Demos
BlogsNewsPress ReleasesIT NewsTutorials
Give us your email and we'll send you the good stuff.
Heather Oliver is a Technical Writer for Constellix and DNS Made Easy, subsidiaries of Tiggee LLC. She’s fascinated by technology and loves adding a little spark to complex topics. Want to connect? Find her on LinkedIn.
Getting a B in school might be acceptable, but a B in DNS won’t cut it. In order for a domain to be resolved properly you must have an A—an A record, that is. Besides, while there are several different DNS record types, a B record isn’t one of them. What does A stand for exactly? It stands for Address, and every single device that connects to the internet has to have one, which is why A records are integral to any DNS configuration.
A records are primarily used for DNS lookups and are the most commonly used record type. In a way, they’re like the central nervous system of DNS, as most other record types rely on their functionality. This is because A records map fully qualified domain names (FQDNs) to numerical IPv4 addresses—the defacto internet protocol still used by most devices.
Did you know?: We’re almost out of IPv4 addresses, which is where AAAA records come in. They function the same as A records, but utilize IPv6 addresses. Currently, they coexist, but eventually, IPv6 will replace IPv4 entirely.
Another important aspect of an A record is that it can be pointed to a subdomain or used at the root of a domain. The root, also known as a “naked domain,” is typically represented by an @ symbol in your DNS record configuration or can appear as a blank name value in your zone file (as seen in the example below).
First, let’s visualize the differences between FQDNs, the root, and subdomains.
FQDN → www.Constellix.com.
Root (naked) → constellix.com
Subdomain → news.constellix or constellix.com/news
Now, let’s look at the structure of an A record.
A (host) Points to (IPv4 address) TTL (Time to Live)
@ (root) → 192.0.2.255 300
news (subdomain) → 192.0.2.256 300
services (subdomain) → 192.0.2.257 300
In summary, an A record is a DNS file that specifies the location of the server your domain is hosted on. This is needed so that resolvers can find your domain on the web. A records can point to a FQDN, a subdomain, or used at the root. You can also have multiple A records for the same domain that point to different IP addresses, depending on your DNS configuration.
Sign up for news and offers from Constellix and DNS Made Easy