Every time someone visits your website, they're relying on a DNS A record to find it. Without this fundamental building block of the internet, your carefully crafted domain name would lead nowhere – just an error message where your website should be.
What is an A record
An A (or “address”) record is your most important DNS record type, creating a direct link between a domain name and an IPv4 address. Think of it as the internet's translation service – servers communicate using numerical IP addresses like 172.217.15.68, but humans need memorable domain names like google.com. The A record bridges this gap.
When someone types your domain into their browser, DNS servers look up the A record to find where your website actually lives. For instance, our website dnsense.io might have an A record pointing to 23.88.99.187. Without this record, your domain simply won't resolve.
A records only handle IPv4 addresses – those familiar four-number combinations separated by dots. Their IPv6 counterparts, AAAA records, handle the newer, longer IP format. Most domains today still rely primarily on A records since IPv4 remains the dominant protocol. However, because of IPv4 address exhaustion, someday we will no longer have enough and some might need to move to IPv6.
Large websites often use multiple A records for the same domain. Google.com, for example, resolves to several different IP addresses for load balancing and redundancy. Most business domains average 3-5 A records across their main domain and subdomains.
How A records work
When you send a request to a website, your browser initiates a DNS lookup process specifically searching for A records. The query travels through multiple DNS servers until it reaches the authoritative nameserver, which returns the IP address stored in the A record.
TTL (Time To Live) values control how long DNS resolvers cache each A record. A TTL of 3600 means the record gets cached for one hour. Lower TTL values mean changes propagate faster but increase DNS query load.
Wildcard A records using *.domain.com syntax catch all undefined subdomains, pointing them to a single IP address. This proves useful for applications that generate dynamic subdomains.
When multiple A records exist for one domain, DNS servers typically rotate through them using round-robin distribution. Each DNS query returns the records in a different order, naturally distributing traffic across multiple servers. There's no built-in priority system – all A records are treated equally.
Standard A record configurations
A very common A record setup involves both the root domain (@) and www subdomain pointing to your web server. Many businesses configure both @ → 172.217.15.68 and www → 172.217.15.68 to ensure visitors reach their site regardless of how they type the URL.
Modern infrastructures often separate services across different subdomains. A typical business might configure:
@ → 23.88.99.187(root domain)www → 23.88.99.187(main website)mail → 188.34.204.193(mail server)
Development and staging environments use A records to point test subdomains to different servers. This keeps dev.your-domain.com and staging.your-domain.com completely isolated from production traffic.
Geographic routing involves creating region-specific subdomains with A records pointing to local servers. Companies might set up us.example.com, eu.example.com, and asia.example.com, each with A records directing to the nearest data center.
Tip: Always verify A records after making DNS changes using online propagation checkers to confirm your updates are resolving correctly.
Need help managing your DNS?
Managing A records becomes complex when you're handling dozens of domains across different registrars. Each provider has its own interface, update times, and quirks.
If you're coordinating DNS changes across multiple providers or need better control over your domain infrastructure, we can help streamline your DNS management.
Questions about A records or DNS management? Contact our team – we aim to help businesses simplify their domain operations every day.