What Is DNS and Why Do Name Servers Matter?

The short answer to what is DNS: DNS translates your domain name (e.g. example.com) into the IP addresses computers use. The servers that hold your domain's records and answer these questions are called name servers. This article explains why name servers matter and why your email can go down when your hosting server does.

How DNS works

When a visitor types your domain, their provider's resolver first finds out which name servers hold your domain, then asks them: “Which IP address serves this name?” With the answer, the browser connects to your web server.

• A / AAAA: the IPv4 / IPv6 address of your site.
• MX: which mail server receives email for your domain.
• TXT: SPF, DKIM, DMARC and other verification data.
• CNAME: an alias pointing one name to another.

DNS is the address book of your website, your email and every service on your domain.

Why name servers matter

If your name servers do not answer, resolvers cannot learn any record of your domain. Even a healthy website on another server becomes unreachable. Name servers should be at least two, run independently in different places, and not share failures with your web and mail servers.

Why email goes down with the hosting server

On shared hosting, DNS records often live on the same server as the website. When that server is down, the site is down and DNS stops answering too. Once cached records expire, sending mail servers cannot find your MX record. This applies even if your mailboxes are hosted elsewhere. Senders usually queue and retry for a while, so short outages mostly mean delayed mail; long outages can cause bounces.

The benefit of separate DNS

• A server problem only affects the services on that server; mail hosted elsewhere keeps working.
• You can point records to a backup server right away.
• With a health-checked record that switch can be automatic.

To be clear: separate DNS does not rescue mailboxes on the failed server itself. It stops the problem from spreading and lets you act quickly.

With Gyro DNS

Gyro DNS publishes your records on two name servers, one in Istanbul and one in Germany. Customers with an active hosting or server service can use the Free plan with up to 5 zones. Read the Gyro DNS announcement for details.