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Manage Service Binding Records (SVCB and HTTPS)

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You can manage service binding records (SVCB and HTTPS) in DNSimple using the DNS record editor.

The instructions in this article assume you are familiar with the service binding record format and usage.

Adding HTTPS records

HTTPS records describe how to connect to an HTTPS service. They do not redirect visitors. To send visitors to another URL, use a URL record instead.

Adding an HTTPS record

To add an HTTPS record

  1. If you have more than one account, select the relevant one from the account switcher at the top-right corner of the screen.
  2. On the header, click the tab.
  3. Locate the relevant domain, and click on the name to access the domain page.
  4. Click at the top right of the domain page.
  5. Click , and select .

  6. On the tab, enter the HTTPS record information.

    • Name: The hostname for the record, without the domain name. For example, if you want to represent www.example.com enter www. Leave it blank to represent the root domain example.com. HTTPS records can be used at the root domain, unlike CNAME records. For a service on a port other than 443, add _port._https in front, for example _8443._https.
    • Priority: The priority value (0-65535). Lower values are preferred. A priority of 0 indicates AliasMode (functions like a CNAME), while a priority greater than 0 indicates ServiceMode (provides alternative endpoints with service parameters).
    • Target: The fully-qualified domain name (FQDN) of either an alias target (AliasMode) or alternative endpoint (ServiceMode). This must be a hostname, not an IP address. Enter . to use the record’s own name as the target.
    • Value: The service parameters (SvcParams), in key=value format. Separate multiple parameters with spaces, and leave the field blank in AliasMode. Common parameters include:
      • alpn=h2,h3 - Lists supported ALPN protocols (e.g., h2 for HTTP/2, h3 for HTTP/3)
      • port=443 - Specifies the port number for the service
      • ipv4hint=192.0.2.1,192.0.2.2 - Provides IPv4 address hints
      • ipv6hint=2001:db8::1 - Provides IPv6 address hints

    As with any other DNS record, you can configure:

    Once you are ready, click to confirm and create the record.

  7. The record is created and visible in the record list.

Adding SVCB records

The process for adding SVCB records is similar to HTTPS records. SVCB records are for protocols other than HTTPS, and their Name usually includes the port and protocol.

Adding an SVCB record

To add an SVCB record

  1. If you have more than one account, select the relevant one from the account switcher at the top-right corner of the screen.
  2. On the header, click the tab.
  3. Locate the relevant domain, and click on the name to access the domain page.
  4. Click at the top right of the domain page.
  5. Click , and select .

  6. On the tab, enter the SVCB record information.

    • Name: Usually the port and protocol, in the format _port._protocol, without the domain name. For example:
      • _8443._tcp for a service on port 8443 over TCP on the root domain
      • _8443._tcp.www for the same service on the www subdomain
      • Leave it blank to create the record for the root domain itself.
    • Priority: The priority value (0-65535). Lower values are preferred. A priority of 0 indicates AliasMode (functions like a CNAME), while a priority greater than 0 indicates ServiceMode (provides alternative endpoints with service parameters).
    • Target: The fully-qualified domain name (FQDN) of either an alias target (AliasMode) or alternative endpoint (ServiceMode). This must be a hostname, not an IP address. Enter . to use the record’s own name as the target.
    • Value: The service parameters (SvcParams), in key=value format. Separate multiple parameters with spaces, and leave the field blank in AliasMode. Common parameters include:
      • port=8443 - Specifies the port number for the service
      • ipv4hint=192.0.2.1,192.0.2.2 - Provides IPv4 address hints to avoid additional DNS lookups
      • ipv6hint=2001:db8::1 - Provides IPv6 address hints to avoid additional DNS lookups
      • alpn=h2,h3 - Lists supported ALPN protocols (primarily used with HTTPS records)
      • mandatory=port,alpn - Lists service parameters that must be understood by the client

    As with any other DNS record, you can configure:

    Once you are ready, click to confirm and create the record.

  7. The record is created and visible in the record list.

Note

SVCB records following the pattern _service._protocol.example.com may create Empty Non-Terminals (ENTs) at intermediate names like _tcp.example.com. If you are using wildcard records, this may affect DNS resolution. Learn more about wildcards and ENTs.

Note

Some hosting providers label fields differently than DNSimple does, which can be confusing if you are copying DNS settings from another provider.

  • In DNSimple, Name = what others might call Host.
  • In DNSimple, Target = the target hostname for the service binding record.
  • In DNSimple, Value = the SvcParams field containing key=value pairs.

Examples

HTTPS record examples

HTTPS record in AliasMode

To create an HTTPS record that aliases example.com to example.net:

  • Name: (leave blank for root domain)
  • Priority: 0 (AliasMode)
  • Target: example.net.
  • Value: (leave blank for simple aliasing)

This creates: example.com. IN HTTPS 0 example.net.

HTTPS record in ServiceMode

To create an HTTPS record that specifies HTTP/2 and HTTP/3 support:

  • Name: (leave blank for root domain)
  • Priority: 1 (ServiceMode)
  • Target: example.com.
  • Value: alpn=h2,h3 port=443

This creates: example.com. IN HTTPS 1 example.com. alpn=h2,h3 port=443

SVCB record examples

SVCB record in AliasMode

To create an SVCB record that aliases a service to another domain:

  • Name: _8443._tcp (for root domain) or _8443._tcp.www (for www subdomain)
  • Priority: 0 (AliasMode)
  • Target: example.net.
  • Value: (leave blank for simple aliasing)

This creates: _8443._tcp.example.com. IN SVCB 0 example.net.

SVCB record in ServiceMode

To create an SVCB record that specifies a custom service with port and protocol hints:

  • Name: _custom._tcp
  • Priority: 1 (ServiceMode)
  • Target: server.example.com.
  • Value: port=8443 ipv4hint=192.0.2.1

This creates: _custom._tcp.example.com. IN SVCB 1 server.example.com. port=8443 ipv4hint=192.0.2.1

Multiple SVCB records for load balancing

To create multiple SVCB records with different priorities for failover:

First record (primary):

  • Name: _service._tcp
  • Priority: 1
  • Target: server1.example.com.
  • Value: port=8443

Second record (fallback):

  • Name: _service._tcp
  • Priority: 2
  • Target: server2.example.com.
  • Value: port=8443

This creates two records that clients will try in order of priority (1, then 2).

Updating service binding records

The process for updating service binding records is the same for both HTTPS and SVCB records.

To update a service binding record (HTTPS or SVCB)

  1. If you have more than one account, select the relevant one from the account switcher at the top-right corner of the screen.
  2. On the header, click the tab.
  3. Locate the relevant domain, and click on the name to access the domain page.
  4. Click at the top right of the domain page.
  5. Locate the service binding record (SVCB or HTTPS) you want to update in the list.

  6. Click the three-dot actions menu at the end of the record row, then select .

  7. Update the information and click to save the record.

Removing service binding records

The process for removing service binding records is the same for both HTTPS and SVCB records.

To remove a service binding record (HTTPS or SVCB)

  1. If you have more than one account, select the relevant one from the account switcher at the top-right corner of the screen.
  2. On the header, click the tab.
  3. Locate the relevant domain, and click on the name to access the domain page.
  4. Click at the top right of the domain page.
  5. Locate the service binding record (SVCB or HTTPS) you want to remove in the list.

  6. Click the three-dot actions menu at the end of the record row, then select .

  7. In the dialog, add a note if you want to record why, then click .

Understanding service binding record modes

Both SVCB and HTTPS records operate in two modes based on the priority value:

  • AliasMode (Priority 0): Functions like a CNAME record but can be used at the apex domain. The record redirects queries to the target hostname specified in the Target field. No service parameters are typically used in AliasMode.

  • ServiceMode (Priority > 0): Provides information about alternative endpoints where the service is available, along with associated service parameters. Multiple service binding records with different priorities can be used to specify fallback endpoints or load balancing.

For more information about service binding record modes, structure, and use cases, see Service Binding Records (SVCB and HTTPS).

Choosing between SVCB and HTTPS

  • Use HTTPS records for websites and other HTTPS services. Browsers look up the HTTPS record type, not SVCB, so an SVCB record has no effect for HTTPS.

  • Use SVCB records for other protocols whose clients support SVCB lookups.

For details, see RFC 9460, which defines both record types.

Have more questions?

If you have additional questions or need any assistance with service binding records, just contact support, and we will be happy to help. You can also read more about DNS hosting at DNSimple.