DNS: Understanding How Your Domain Name is Resolved

What is DNS? Simply put, it is the phonebook of the web. DNS, or Domain Name System, is the service that translates a name like monentreprise.com into an IP address, the string of numbers that actually identifies the server. Without it, you would have to remember an IP address for every website. Understanding how it works helps you read a DNS zone, point your domain to the correct server, and troubleshoot a website or emails.

DNS: The Web's Phonebook

The role of DNS is resolution: converting a human-readable name into an IP address usable by machines. The request starts from your device, goes up to a resolver, then queries the servers that know the domain, until you get the IP address of the server hosting the site. This resolution is fast—typically a few milliseconds—and its result is cached so that the entire path doesn't need to be retraced with every visit.

This mechanism is defined by public standards, RFC 1034 and 1035, which describe the architecture of the naming system. This is what guarantees that DNS works the same way everywhere in the world, regardless of the provider.

The speed of this resolution also depends on the distance to the servers: this is the subject of latency and hosting.

What is DNS, in practice

Imagine calling a friend without knowing their number: you look up their name in your directory, which gives you the number. DNS plays this directory role for the Internet.

When you visit monentreprise.com, your device queries the DNS, which responds "this name corresponds to the server with IP address 203.0.113.10". Your browser then connects to that address. You only see the name; machines only communicate with each other using IP addresses.

Name Servers and DNS Zone

Two concepts are often confused:

• Name servers: the machines that answer questions about your domain. They are declared at the registrar. When you buy a domain, you specify which name servers are responsible for it.
• The DNS zone: the file containing all the records for the domain. It lives on the name servers.

In concrete terms: the name servers say "I hold the information," and the zone says "here is where each service points." To find out which name servers to use with a host, consult the article What are your DNS or name servers.

When you change registrars, it is this declaration that changes hands: see transfer a domain name.

Essential records: A, CNAME, MX, TXT

A DNS zone is a list of records. The four most common types cover most needs:

• A: associates a name with an IPv4 address. This is the record that points monentreprise.com (and www.monentreprise.com) to the web server's IP address.
• CNAME: creates an alias to another name. Useful for having www.monentreprise.com automatically follow monentreprise.com.
• MX: designates the servers that receive emails for the domain, with a priority. Without a correct MX record, your messages go nowhere.
• TXT: contains free text, used notably to prove domain ownership (Google verification) or to publish SPF and DKIM policies that protect your emails.

A misconfigured record is the most common cause of "the site does not display" or "emails bounce." To modify these values, see Domain Name (DNS) Configuration.

TTL and Propagation

Each record has a TTL (time to live), a lifetime in seconds. It tells resolvers how long to keep the response in cache before requesting it again. A high TTL reduces load and speeds up repeated visits; a low TTL allows an address change to happen faster.

This is what explains the delay after a modification: if the TTL is 24 hours, some visitors will still see the old value until the cache expires. Before a migration, you lower the TTL in advance so that the switch is visible quickly. This principle is detailed in our guide Moving hosts without downtime.

DNS and Emails: The Role of MX

Emails have their own path in the DNS zone. The MX record indicates which server accepts mail for the domain, and its priority allows you to define a primary server and a backup. Alongside, SPF and DKIM TXT records help recipients verify that your messages are legitimate, limiting their passage to spam.

If you move your email boxes to another provider, it is the MX record that needs to be changed, not just the name servers. The procedure is explained in Modify MX Records Configuration (Advanced).

Verifying Your Zone Configuration

Before concluding that a site "is down," check the zone:

1. Ask the resolver what IP address it returns for your domain, and compare it to the server's actual address.
2. Check the A record for the naked domain and www.
3. Test the MX record if emails are causing problems.
4. Check the TTL to know how long a fix will take to propagate.

Free online tools allow you to query a domain's zone from the outside, avoiding reasoning based on a value cached on your own machine.

And for the zone to continue existing, the domain must remain yours: not losing your domain name covers renewal.

Summary

DNS is the layer that connects your domain name to your web and email servers. Mastering the four basic records—A, CNAME, MX, TXT—and the TTL is enough to understand the vast majority of "site not responding" failures and messaging issues.

To manage your DNS zone in the same place as your domain, with records edited from the portal, discover Atlas Hoster domain name offers.

Frequently Asked Questions

What is the difference between a name server and an A record? The name server holds the domain's zone; the A record, inside this zone, points a specific name to an IP address.

Why doesn't my DNS change show up immediately? Due to the TTL: resolvers keep the old response in cache until it expires. The lower the TTL, the faster the change propagates.

Is an MX record mandatory? Yes, to receive emails on your domain. Without an MX, mail addressed to contact@monentreprise.com cannot be delivered to any server.