ANAME is an extended record type unique to this service.

According to the original DNS specifications, CNAME records cannot be placed at the zone apex (record having the same name as the zone name). You can use ANAME instead of CNAME in a case where you want to specify an external resource as a name, not as an IP address, for the zone apex.

ANAME is almost identical to a feature that is called ALIAS in other companies’ service.

• You can set one ANAME only to the zone apex (record having the same name as the zone name).
• Use CNAME for records other than the zone apex.
• Because the load distribution function with DNS does not work for host names, such as CDN, for which DNS response changes dynamically, use of ANAME records is not recommended. Note that the same is true in a case where the host name specified by ANAME is CNAME and the canonical name of CNAME returns a dynamic response.

Let us assume that a value "aname.example.com." is registered with the ANAME record of the zone apex in the name of "example.jp." below.

• The IPv4/v6 address of "aname.example.com." is the response returned to an inquiry of an A/AAAA record of "example.jp."
  • When multiple IP addresses are set, up to four A and AAAA records each are captured.
• Name resolution is performed for each TTL passage of "aname.example.com." and updated in the zone.
  • If an extremely small TTL is set, however, the update interval may become greater than that.
  • The name of "aname.example.com." is not resolved at the timing of an inquiry to the A/AAAA record of "example.jp."
• If no A/AAAA record exists in "aname.example.com.", an empty response is returned to the inquiry to the A/AAAA record of "example.jp."
• When name resolution of "aname.example.com." ends in error, the IPv4/v6 address obtained when name resolution succeeded last time continues to be used.
• If record types other than A/AAAA records exist in "aname.example.com.", they are ignored.
• If "example.jp." is supposed to adopt DNSSEC signing, DNSSEC signing will be implemented and a response will be sent even when "aname.example.com." is not DNSSEC signed and, strictly speaking, completeness cannot be guaranteed.
  • If you do not agree to the previously explained behavior, please refrain from using ANAME.
• When you use this service as a secondary name server, zones in which ANAME records are written cannot be transferred from your primary name server.
• When you use this service as the primary name server, on the other hand, zones in which ANAME records are rewritten to A/AAAA records are transferred to your secondary name server.