Everything you need to know about DNS records
Discover the different types of DNS records available in an OVHcloud DNS zone
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 entries called DNS records and acts as the domain name's switchboard.
This guide introduces the different types of DNS records available in an OVHcloud-managed DNS zone. It complements 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, for example, make your website unavailable or stop your email addresses receiving emails.
The list below describes the purpose and specifics of each record, to help you understand how to manage your DNS services.
Pointer records
Click a tab below to view the corresponding record.
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 hosting your website.
Four A characters, because this record is encoded on four times as many bits as the historical A record.
Links a domain name to an IPv6 address. For example, the IPv6 address of the server hosting your website.
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, www.domain.tld uses 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
Creates an alias for all subdomains of a domain name, which saves creating many CNAME records (a CNAME record redirects a single subdomain to a single target).
Example: a DNAME record from domain.tld to ovh.com redirects all subdomains of domain.tld (such as dname.domain.tld and xxx.domain.tld) to the matching subdomains of ovh.com (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
Defines 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, use those servers in the DNS servers tab of your OVHcloud Control Panel. See our guide Modifying an OVHcloud domain name's DNS servers.
Warning
Do not modify the NS records in your DNS zone via Actions on my zone > Edit in text mode, in favour of DNS servers external to OVHcloud. This DNS zone works only with OVHcloud DNS servers.
Email records
Click a tab below to view the corresponding record.
Mail eXchanger
Links a domain name to an email server.
For example, 10 mx1.mail.ovh.net is one of the OVHcloud email servers used by OVHcloud email solutions.
Your email provider may have several email servers, in which case you must create several MX records. See our guide Configure an MX record for email management.
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
Prevents spoofing of email addresses using your domain name. For example, the record v=spf1 include:mx.ovh.com ~all tells the receiving server that only the outgoing servers of your OVHcloud email service are legitimate. You can enter it as a TXT record or build it with the SPF form in the Control Panel.
See our guide How to improve email security with an SPF record.
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 they offer this feature). You can enter it as a TXT record.
See our guide How to improve email security with a DKIM record.
Domain-based Message Authentication, Reporting and Conformance
Helps authenticate emails in association with SPF and/or DKIM methods. Your email provider gives you this value (if they offer this feature), and will at least be associated with an SPF or DKIM record.
Refer to our documentation "How to improve email security with a DMARC record" to find out more.
Extended records
Click a tab below to view the corresponding record.
TeXT
Lets you add any text value to 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 Edit in text mode feature described in our guide "Editing an OVHcloud DNS zone" (for expert users).
SeRVice resource
The SRV record defines the address of the server that manages a service — for example a SIP server, or a server that auto-configures email software.
Certification Authority Authorization
The CAA record lists the certificate authorities authorised to issue 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 telecommunications to route a request from a mobile device to a server. It can be combined with an SRV record to generate target URIs (Uniform Resource Identifiers) dynamically.
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 Authentication
Stores the fingerprint (hash) of an SSL/TLS certificate directly in your domain name's DNS zone.
This record is used for the DNS-based Authentication of Named Entities (DANE) protocol.
The DANE protocol lets a client (web browser, email client, FTP client, SSH client, etc.) read the TLSA record and check that the SSL/TLS certificate presented for a domain name is the one expected for it.
For more details, see the Internet Engineering Task Force (IETF) website.
Responsible Person
Specifies the email address of the person responsible for the domain name. It can be combined with a TXT record to provide additional information.
If needed, find more details on the Internet Engineering Task Force (IETF) (EN) website.
SerViCe Binding
This record groups several pieces of information so the browser can connect to your website faster: for example, that the website supports HTTP/2 or HTTP/3, that a given IP address (IPv4 and/or IPv6) should be preferred, or that a specific port should be used. The browser retrieves all of this in a single request.
This record has 2 modes:
- Alias Mode: activated by a priority of 0. Unlike a CNAME record, it can redirect the domain name itself (apex) to another domain name or subdomain.
- Service Mode: activated by a priority other than 0. This mode lets you define the parameters to apply to your domain name (for example alpn="h2,h3", ipv4hint="203.0.113.0", ipv6hint="2001:db8:1:1b00:203:0:113:0", port="XXXX"), even when it is not 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 record but is specific to the HTTP protocol. It groups several pieces of information so the browser can connect to your website faster: for example, that the website supports HTTP/2 or HTTP/3, that a given IP address (IPv4 and/or IPv6) should be preferred, or that a specific port should be used. The browser retrieves all of this in a single request.
This record has 2 modes:
- Alias Mode: activated by a priority of 0. Unlike a CNAME record, it can redirect the domain name itself (apex) to another domain name or subdomain.
- Service Mode: activated by a priority other than 0. This mode lets you define the parameters to apply to your domain name (for example alpn="h2,h3", ipv4hint="203.0.113.0", ipv6hint="2001:db8:1:1b00:203:0:113:0", port="XXXX"), even when it is not 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 given in the "CNAME" tab of the "pointer records" section also applies here.
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, you cannot create a CNAME record for subdomain-with-its-own-DNS-zone.domain.tld in its own DNS zone, but you can for its subdomains, 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
How to improve email security with an SPF record
Protect your domain name against cache poisoning with DNSSEC
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