Everything you need to know about DNS records
Objective
DNS means Domain Name System and is a set of elements (DNS servers, DNS zones, etc.) that map a domain name to an IP address.
First, we recommend reading our guides “Everything you need to know about DNS servers” and “Everything you need to know about DNS zone” in this order.
A domain name’s DNS zone is its configuration file. It consists of technical information, called DNS records. The DNS zone is a sort of referral center for a domain name.
The purpose of this guide is to introduce you to the different types of DNS records available in a DNS zone managed by OVHcloud. It is complementary to the following guides:
Find out about the different types of DNS records available in an OVHcloud DNS zone.
Instructions
DNS records
Editing a DNS zone is a sensitive procedure. Incorrect changes could make your website unavailable, for example, or prevent your email addresses from receiving new emails.
The list below includes the objectives and specifics of each registration. This will give you a better understanding of how you manage your DNS services.
Pointer records
Select the record you want by clicking each of the following tabs.
Address
Links a domain name to a X.X.X.X IPv4 address (where X is a number between 0 and 255). For example, the IPv4 address of the server your website is hosted on.
Four A characters because this record is encoded on four times more bits than the historical A field.
Links a domain name to an IPv6 address. For example, the IPv6 address of the server your website is hosted on.
Info
IPv6 addresses are gradually being set up to compensate for the lack of IPv4 addresses due to the continuous expansion of digital usage. The 128-bit encoding of IPv6 addresses allows for a larger number of IP addresses.
However, if your server already has an IPv4 address, we recommend using it over IPv6.
IPv6 addresses are not yet correctly interpreted across the Internet, which can cause disruptions to display or access.
Canonical NAME
Uses the IP address of another domain name by creating a link called an alias. For example, if www.domain.tld is an alias of domain.tld, this indicates that www.domain.tld will use the IP address of domain.tld.
Danger
A TXT record using the same domain or subdomain as a CNAME record will disrupt the CNAME record. Your CNAME record will only work partially or not at all.
Warning
By convention, CNAME records cannot be used directly by a domain name in its own DNS zone. Indeed, the domain alone must obligatorily and directly point to an IP address with a type A field (or AAAA if it is an IPv6).
To use the example given above, you cannot create a CNAME record for the domain domain.tld in the DNS zone you created for it.
However, you can create CNAME records with all subdomains (examples: subdomain.domain.tld or www.domain.tld) of the domain name domain.tld in the DNS zone created for domain.tld.
If you would like to go further technically on this subject, you can find at the bottom of this page a particular use case concerning CNAME records and DNS zones created for subdomains.
Delegation NAME
Allows to generate an "alias" for all subdomains of a domain name. This record avoids creating a multitude of CNAME records. A CNAME record redirects only one subdomain to a single target, independently.
Example: By creating a DNAME record from domain.tld to ovh.com, all subdomains of domain.tld (such as dname.domain.tld and xxx.domain.tld) will be redirected respectively to subdomains of ovh.com (such as dname.ovh.com and xxx.ovh.com).
In other words, the DNAME record indicates that dname.domain.tld and xxx.domain.tld must display the results of dname.ovh.com and xxx.ovh.com, respectively.
Warning
However, domain.tld as a domain name will not display the target of the ovh.com domain name, because the DNAME record is only valid for the subdomains of the domain names defined in the DNAME record.
Also, using one of the examples above, if the target subdomain xxx.ovh.com does not point to anything, then the DNAME record will not display anything for xxx.domain.tld either.
Tip
The DNAME record is usually used for company name changes. It can also be set up when a user has several domain name extensions (.fr, .net, .com, .info, etc.) to redirect them easily.
Name Server
Define the DNS servers associated with your DNS zone. For example, if the NS records in your DNS zone display the servers dnsXX.ovh.net and nsXX.ovh.net, you will need to use them in the DNS servers tab in your OVHcloud Control Panel. Please refer to our guide on Editing DNS servers for an OVHcloud domain name for more information.
Warning
Do not modify the NS records in your DNS zone using the button Change in text format, in favour of DNS servers external to OVHcloud. This DNS zone works only with OVHcloud DNS servers.
Email records
Select the record you want by clicking each of the following tabs.
Mail eXchanger
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 solution. Your email provider may have several email servers. Several MX fields must therefore be created. Please read our guide on Adding an MX record to your domain name’s configuration.
Warning
In general, we recommend using servers from the same email provider in your DNS zone.
If you already have email services from another email provider and you are adding your new email provider’s servers in parallel (without replacing them), you risk randomly receiving your emails from either of your two email providers.
Sender Policy Framework
Avoids potential identity theft on email addresses using your domain name (spoofing). For example, the record v=spf1 include:mx.ovh.com ~all indicates that only outgoing servers linked to your OVHcloud mail service can be considered legitimate by the incoming server. You can enter this record as a TXT record, or via our automatic configuration system.
For further information, please refer to our guide on Adding an SPF record to your domain name’s configuration.
DomainKeys Identified Mail
Checks the authenticity of the sender’s domain name, and ensures the integrity of the email sent. The DKIM record is a key that consists of several characters. The DKIM key is provided by your email service provider (if this feature is offered by them). You can enter it as a TXT record.
For further information, please refer to our guide on Configure a DKIM record.
Domain-based Message Authentication, Reporting and Conformance
Helps authenticate emails in association with SPF and/or DKIM methods. This value will be given to you by your email provider (if this feature is offered by them), and will at least be associated with an SPF or DKIM record.
Refer to our documentation “Configuring a DMARC record on your domain name” to find out more.
Extended records
Select the record you want by clicking each of the following tabs.
TeXT
Allows you to add the value of your choice, in text format, in your domain name’s DNS zone. This record is often used during verification/validation or security processes.
Warning
The TXT record is limited to 255 characters. However, in some cases, you can split your value into several records. Ask your service provider if they request to enter a value that exceeds the 255-character quota.
However, this limit does not exist if you use the Modify in text mode feature described in our guide "Editing an OVHcloud DNS zone" (for expert users).
SeRVice resource
The SRV record is used to define information on the address of a server that manages a service. For example, it can indicate the address of a SIP server or the address of a server that allows the automatic configuration of an email software.
Certification Authority Authorization
The CAA record is used to list certificate authorities authorised to deliver SSL certificates for a domain name.
Warning
If you configure a CAA record for a domain name, this configuration will also apply to all subdomains of the same domain name.
If you use a Let's Encrypt SSL certificate with your domain name on an OVHcloud Web Hosting plan, and you use a CAA record, the CAA record will prevent the Let's Encrypt SSL certificate from being regenerated.
Name Authority PoinTeR
Used in telecommunication to direct a request from a mobile device to a server. An SRV record can be associated to dynamically generate target URIs (Uniform Resource Identifier).
LOCation
Used to populate location information (including latitude, longitude and altitude).
Secure SHell FingerPrint
Used to fill in the fingerprint of an SSH public key.
Transport Layer Security Authentification
Used to fill in the fingerprint of an SSL/TLS certificate. You can use it to save the hash of a certificate directly in your domain name’s DNS zone via a DNS record.
This record is used for the DNS-based Authentication of Named Entities (DANE) protocol.
The DANE protocol allows a client (internet browser, email client, FTP client, SSH client, etc.) to view the TLSA record. This way, they can ensure that an SSL/TLS certificate used for a domain name is the one certifying the same domain name.
If you need further information, please visit the Internet Engineering Task Force (IETF) website.
Responsible Person
This record allows you to specify the email address of the person responsible for the domain name. This record can also be combined with a TXT type DNS record to provide additional information.
If needed, find more details on the Internet Engineering Task Force (IETF) (EN) website.
SerViCe Binding
This DNS record can group several pieces of information to allow a faster and more efficient connection to your website. It also allows, for example, to directly inform the web browser that the website is compatible with HTTP 2 or HTTP 3, that it should prioritise the use of an IP address (IPv4 and/or IPv6) mentioned as a parameter, or to use a specific access port. This allows the web browser to retrieve several pieces of information in a single request.
This record has 2 modes:
- Alias Mode: this mode is activated when you specify a priority equal to 0. Unlike CNAME type DNS records, it allows you to redirect a domain name from its own DNS zone (apex) to another domain name or subdomain.
- Service Mode: this mode is activated when you specify a priority different from 0. It is in this mode that you can define the parameters you wish to apply to your domain name (example parameters: apln="h2,h3", ipv4hint="203.0.113.0", ipv6hint="2001:db8:1:1b00:203:0:113:0", port="XXXX", etc.). In Service mode, you can apply these parameters directly to your domain name, even if it is not to be used as an alias for another domain name.
If needed, find more details on the Internet Engineering Task Force (IETF) (EN) website.
Hyper Text Transfer Protocol Secure
This record works like the SVCB type DNS record, but unlike it, it is more specific to the HTTP protocol. It can group several pieces of information to allow a faster and more efficient connection to your website. It also allows, for example, to directly inform the web browser that the website is compatible with HTTP 2 or HTTP 3, that it should prioritise the use of an IP address (IPv4 and/or IPv6) mentioned as a parameter, or to use a specific access port. This allows the web browser to retrieve several pieces of information in a single request.
This record has 2 modes:
- Alias Mode: this mode is activated when you specify a priority equal to 0. Unlike CNAME type DNS records, it allows you to redirect a domain name from its own DNS zone (apex) to another domain name or subdomain.
- Service Mode: this mode is activated when you specify a priority different from 0. It is in this mode that you can define the parameters you wish to apply to your domain name (example parameters: apln="h2,h3", ipv4hint="203.0.113.0", ipv6hint="2001:db8:1:1b00:203:0:113:0", port="XXXX", etc.). In Service mode, you can apply these parameters directly to your domain name, even if it is not to be used as an alias for another domain name.
If needed, find more details on the Internet Engineering Task Force (IETF) (EN) website.
Tip
Below is a concrete example of setting up an alias (apex) using an HTTPS-type DNS record:
The website domain.tld is hosted behind a CDN infrastructure (for example: cdn.provider.tld).
Thanks to the HTTPS-type DNS record, the domain name domain.tld can directly inform compatible web browsers that the HTTPS service should be resolved by the CDN provider cdn.provider.tld. This is done without redirections and without manual management of IP addresses.
For this, the HTTPS-type DNS record must specify:
- Priority: 0.
- Target: cdn.provider.tld.
- Settings: Leave the field empty.
Thus, it is the resolution of cdn.provider.tld that will indicate the parameters to use for domain.tld.
Special use case: CNAME records
Some users create DNS zones directly for a domain name’s subdomain (for example, subdomain-with-its-own-DNS-zone.domain.tld). The rule specified earlier in the "CNAME" tab of the “pointer records” section will then also apply in this scenario.
Since the DNS zone is created for the subdomain (in our example subdomain-with-its-own-DNS-zone.domain.tld), the subdomain is then considered a fully qualified domain name in its DNS zone.
As a result, in this specific case, you will not be able to create a CNAME record for subdomain-with-its-own-DNS-zone.domain.tld in the DNS zone you have created for it. However, you can create CNAME records, such as subdomain.subdomain-with-its-own-DNS-zone.domain.tld or xxx.subdomain-with-its-own-DNS-zone.domain.tld.
Go further
Everything you need to know about DNS servers
Everything you need to know about DNS zone
Add an SPF record to your domain name’s configuration
Protect your domain name against cache poisoning with DNSSEC
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