A.2 Types of Resource Records

A resource record (RR) contains data associated with domain names. This data is represented by and is subordinate to the resource record set (RRset) of a zone container.

The following types of resource records can be created:

  • A6: Maps a domain name to an IPv6 address.

    Specify the following for this option:

    • Prefix Length: This can be any value between 0 and 128.

    • Address Suffix: The address suffix need not be specified if the prefix length is 128.

    • Prefix Name: The domain name of the server. This need not be specified if the prefix length is 0.

  • A: Maps a domain name to an IP address.

    You must specify the 32-bit IPv4 address that maps to the associated domain for this option.

  • AAAA: A 128-bit IPv6 address that is encoded in the data portion of the resource record in the network byte order.

  • AFSDB: The AFS system uses DNS to map from a domain name to the name of an AFS cell database server. It contains the following data:

    • Subtype: A 16-bit integer.

    • Hostname: The domain name of the host server.

  • CNAME: Specifies the canonical or primary name for the owner. Because the owner name is an alias, you must specify the domain name of the aliased host if you select this option.

  • DNAME: Specifies an alternate name to map the entire subtree of the domain namespace.

    You must specify the target domain name for this option.

  • HINFO: Specifies host information in the form of the following parameters:

    • CPU: A character string that specifies the CPU type.

    • OS: A character string that specifies the operating system type.

  • ISDN: An ISDN (Integrated Service Digital Network) number is a telephone number integrating the telephone and data network service to a common service. It contains the following parameters:

    • ISDN Address: A character string specifying the ISDN address.

    • Sub Address: A character string specifying the subaddress. This parameter is optional.

  • LOC: Specifies the location information in the globe. If you select this option, you must specify the following:

    • Latitude: Specify the degree of the latitude, minutes, and seconds of the globe enclosing the specified host. Select the direction.

    • Longitude: Specify the degree of the latitude, minutes, and seconds of the globe enclosing the specified host. Select the direction.

    • Altitude: Specify the altitude of the globe enclosing the specified host in meters.

    • Size: Specify the diameter of the globe enclosing the specified host in meters.

    • Horizontal precision: Specify the horizontal precision of the globe enclosing the specified host in meters.

    • Vertical precision: Specify the vertical precision of the globe enclosing the specified host in meters.

  • MB: Specifies the domain name of the mailbox address.

  • MG: A domain name that specifies a mailbox that is a member of the mail group specified by the domain name.

  • MINFO: Specifies mailbox or mail list information in the form of the following parameters:

    • Responsible MailBox: A domain name that specifies the mailbox that is responsible for the mailing list or mailbox.

    • Error Message MailBox: A domain name that specifies the mailbox that is to receive error messages related to the mailing list or mailbox.

  • MR: A domain name that specifies the mailbox that is the proper rename of the specified mailbox.

  • MX: Specifies a mail exchange resource record in the form of the following parameters:

    • Preference: A 16-bit integer that specifies the preference given to this resource record among others at the same owner.

    • Exchange: A domain name that specifies a host willing to act as a mail exchange for the owner name.

  • NS: Specifies a domain name for an authoritative name server for the specified class and domain.

  • PTR: A domain name that points to some location in the domain namespace.

  • PX: Contains X.400 mail mapping information with the following parameters:

    • Preference: A 16-bit integer that specifies the preference given to this resource record among others at the same owner.

    • MAP822: A domain name element containing the RFC822 part of the MCGAM.

    • MAPX400: A domain name element containing the value derived from the X.400 part of the MCGAM.

  • RP: Provides a standard method of associating responsible person identification with any name in the DNS with the following parameters:

    • Responsible Person’s Mailbox: A domain name that specifies the mailbox for the responsible person.

    • TXT-RR Domain Name: A domain name for the TXT RRs that exist.

  • RT: Specifies the routing information with the following parameters:

    • Preference: A 16-bit integer representing the preference of the route.

    • Intermediate: The domain name of a host that serves as an intermediate in reaching the host specified by the owner.

  • SRV: Specifies the location of services with the following parameters:

    • Service: The symbolic name of the desired service.

    • Proto: The TCP and UDP are the most useful values for this field.

    • Priority: The priority of the target host.

    • Weight: A load balancing mechanism when selecting a target host among those that have the same priority.

    • Port: The port on the target host running the service.

    • Target: The domain name of the target host.

  • TXT: Specifies text data in the form of a character string.

  • WKS: Describes the well-known services supported by a protocol on a particular host with the following parameters:

    • Address: A 32-bit Internet address.

    • Protocol: An 8-bit IP protocol number.

    • Available Services: A variable-length bitmap.

  • X25: Specifies a PSDN (Public Switched Data Network) address.