What is a DNS zone?

Understanding the concept of DNS 

The acronym DNS, meaning  Domain  Name System  , is a set of elements allowing a domain name to be matched with an IP address.

For example, when you want to access the site  mydomain.ovh , the DNS set will direct your request to the IP address of the server hosting the site  mydomain.ovh .

It is important to differentiate between  DNS servers  and the  DNS zone . The  DNS zone is configured at the DNS server level.

You can find information relating to  DNS servers  and how to modify them in our guide “  Modifying the DNS servers of an OVHcloud domain name  ”.

If we take the example above, when you type mydomain.ovh , you query the DNS servers  for this domain name. These servers contain the DNS zone  of the domain name mydomain.ovh  where the IP address of the hosting of mydomain.ovh is entered . This allows your browser to display the website mydomain.ovh. This is called a DNS resolution.

The DNS zone

A domain name’s DNS zone is a configuration file containing records . These records are used to link your domain name to the servers that host your internet services, such as websites (via the A record) or email addresses (MX record).

Prerequisites

• Have access to manage the domain name concerned from your  OVHcloud customer area .
• Be connected to your  OVHcloud customer area .
• Use the OVHcloud configuration (its DNS servers) for the domain name in question.

• If your domain name does not use OVHcloud’s DNS servers, you must make the change from the interface of the service provider managing the configuration of your domain name.
• If your domain name is with OVHcloud, you can check whether they are using our configuration. To do this, go to your  OVHcloud customer area , in the tab  Serveurs DNS for the domain name in question.

In both cases above, be careful when making DNS server changes. The old configuration that could have been applied to your domain name will no longer be active if you have not previously reconfigured and customized the new DNS zone present at OVHcloud.
You can only have one active DNS zone at a time per domain name.

In practice

Access the management of an OVHcloud DNS zone

Log in to your  OVHcloud customer area  in the section  Web Cloud. Click on  Noms de domaine, then choose the domain name concerned. Finally, go to the tab  Zone DNS.

The table that appears displays a DNS record for each row associated with your domain name at OVHCloud. You can filter the contents by record type or by domain.

DNS records

Editing a DNS zone is a sensitive process  : making an inappropriate change could, for example, make it impossible to access your website or receive new messages at your email addresses.

Understanding these different records will help you better understand the changes you’ll make if you edit your domain name’s DNS zone. We strongly encourage you to review the list below, which outlines the objectives and specifics of each record.

Timekeeping records

• A  ( Address ): Connects a domain name to an IPv4 address  X.X.X.X (where the  X are numbers between  0 and  255). For example, the IPv4 address of your website server.
• AAAA  (4 A’s  because  this record is encoded on four times as many bits as the  historical A pointer field  ): Connects a domain name to an IPv6 address. For example, the IPv6 address of your website server.
• CNAME  ( Canonical Name ): Uses the IP address of another domain name by creating a link called an alias. For example, if  www.mydomain.ovh  is  an alias of  mydomain.ovh , this indicates that  www.mydomain.ovh  will use the IP address of  mydomain.ovh .

A TXT record using the same domain or subdomain as a CNAME record will disrupt the CNAME record’s functionality. Your CNAME record will then only work partially or not at all.

By convention, CNAME fields cannot be directly used by a domain in its own DNS zone. Indeed, the domain alone must directly point to an IP address with an A field (or AAAA if it is IPv6).

• NS field  ( Name Server  ): Defines the DNS servers associated with your DNS zone. For example, if the NS records in your DNS zone display the servers  dns19.ovh.net and  ns19.ovh.net  , then you will need to use these in the tab   of your OVHcloud Control Panel. See our documentation ”  Modifying the DNS servers of an OVHcloud domain name  ” for more information.Serveurs DNS

Email records

• MX  ( Mail e X changer): Links a domain name to an email server. For example, the address  10 mx1.mail.ovh.net  corresponds to one of the OVHcloud email servers when you have an OVHcloud email offer. It is likely that your email provider has several email servers: several MX fields must therefore be created. Consult our documentation ”  Adding an MX field to your domain name configuration  “.

• SPF  ( Sender Policy Framework  ): Helps prevent potential identity theft on email addresses using your domain name ( spoofing ). For example, the record  indicates that only sending servers linked to your OVHCloud email offer can be considered legitimate by the   receiving server. You can enter this record as a TXT field or via our automatic configuration system. See our documentation ”  Adding an SPF field to your domain name configuration  ” to learn more.v=spf1 include:mx.ovh.com ~all
• DKIM  ( Domain Keys I dentified  Mail ): Allows you to verify the authenticity of the sender ‘s  domain name and ensure the integrity of the email sent. The DKIM record is presented in the form of a key composed of several characters . The DKIM key is provided by your email provider (if this feature is offered by the latter), it is possible to enter it in the form of a TXT field.
• DMARC  ( Domain –  based  Message Authentication ,  Reporting and  Conformance ): Contributes to email authentication in conjunction with SPF and/or DKIM. This value will be provided by your email provider (if this feature is offered by the latter), and will at least be associated with an SPF or DKIM record.

Edit the OVHcloud DNS zone of your domain name

You can edit the OVHcloud DNS zone for your domain name by adding, modifying, or deleting a DNS record. There are two ways to do this:

Manually edit the area in text mode

For advanced users only. Also, be very careful with syntax when editing.

From the tab  Zone DNS, click on  Modifier en mode textuel then follow the steps that appear.

Use our setup wizards

From this point on, this documentation will only cover configuration via our wizards.

Have the information you need to modify in your OVHcloud DNS zone ready. If you are making this change at the request of a service provider, they must provide you with a list of the items to be modified.

Add a new DNS record

Zone DNS To add a new DNS record, from your domain name  tab  , click the button Ajouter une entrée to the right of the table. Select the DNS field type and follow the steps.

We encourage you to first check that this record does not already exist and does not point to a different target. To do this, filter the table contents by record type or domain. If the record already exists, we encourage you to modify it using the procedure described below.

When your record’s target is a URL, remember to punctuate it. If you don’t, your domain name will automatically be added to the end of your target.

Example: You want to create a CNAME record from  test.mydomain.ovh  to  mydomain.ovh .

You must then have as target  mydomain.ovh.  and not  mydomain.ovh  without the  .  at the end.

Modify an existing DNS record

To edit a DNS record, still from the tab  Zone DNS in your customer area, click on the icon  ... in the table to the right of the selected entry. Then click  Modifier l'entrée and follow the steps that appear.

Delete a DNS record

To delete a DNS record, still from your customer area tab  Zone DNS , click the icon  ... in the table to the right of the selected entry. Then click  Supprimer l'entrée and follow the steps that appear.

You can delete multiple entries at once by checking them from the left side of the table and then clicking the button  Supprimer.

Reset DNS zone

Resetting your DNS zone allows you to:

• or return to a minimal configuration with the default OVHcloud entries.
• or revert to an empty DNS zone (except for NS fields), to set further manual configuration.

From the tab  Zone DNS, click on  Réinitialiser ma zone DNS then follow the steps that appear.

You have the choice between:

• Oui, je veux réinitialiser ma zone DNS avec les entrées minimalesThis option allows you to direct your domain name and email service to:
  • one of your Web Cloud services available in your OVHcloud customer area.
  • the OVHcloud redirection service, accessible via  Redirection your domain name tab in the  Noms de domaine and  sections Emails.
  • the function  Personnalisé. Enter the field  A and/or  MX of your choice.
• Non, mais je veux réinitialiser ma zone DNSYour DNS zone will then be empty, except for the NS entries which will be automatically attached to the OVHcloud DNS servers in your DNS zone.

Before resetting your DNS zone, make sure your domain name is not attached to any services in use, such as a website or email addresses.

The propagation time

Once the DNS zone of your domain name has been modified, a propagation time of up to 24 hours is required for the changes to take effect.

If you want to reduce this delay for future editions of your OVHcloud DNS zone, you can modify it, to a certain extent, by adjusting the TTL ( Time To Live ) which will apply to all records in the DNS zone. To do this, go to the tab  Zone DNS in your customer area, click on the button  TTL par défaut and then follow the steps that appear.

You can also change the TTL of a DNS record. However, we can only do this on one record at a time, whether you’re editing or adding it.

Special use case: the use of CNAME records

Some users create DNS zones directly for a domain’s subdomain (e.g.,  subdomain-with-its-own-DNS-zone.mydomain.ovh ). The rule specified  earlier  in this guide also applies in this case.

The DNS zone being created for the subdomain (in our example  subdomain-having-its-own-DNS-zone.mydomain.ovh ), the latter is then considered as a domain in its own right in its DNS zone.

Therefore, in this specific case, you will not be able to create a CNAME field for  subdomain-with-its-own-DNS-zone.mydomain.ovh  in the DNS zone you created for it. However, you can create CNAME fields such as  subdomain.subdomain-with-its-own-DNS-zone.mydomain.ovh  or  xxx.subdomain-with-its-own-DNS-zone.mydomain.ovh .