HP-UX Reference (11i v2 04/09) - 4 File Formats (vol 8)

n
named.conf(4) named.conf(4)
Resource Records
A domain name identifies a node. Each node has a set of resource information, which may be empty. The
set of resource information associated with a particular name is composed of separate RRs. The order of
RRs in a set is not significant and need not be preserved by nameservers, resolvers, or other parts of the
DNS. However, sorting of multiple RRs is permitted for optimization purposes, for example, to specify
that a particular nearby server be tried first.
The components of a Resource Record are:
owner name
the domain name where the RR is found.
type an encoded 16-bit value that specifies the type of the resource in this resource record. Types
refer to abstract resources.
TTL the Time To Live (TTL) of the RR. This field is a 32-bit integer in units of seconds, and is
primarily used by resolvers when they cache RRs. The TTL describes how long a RR can be
cached before it should be discarded.
class an encoded 16-bit value that identifies a protocol family or instance of a protocol.
RDATA the type and sometimes class-dependent data that describes the resource.
The following are the types of valid RRs (some of these listed, although not obsolete, are experimental (x)
or historical (h) and no longer in general use):
A a host address.
A6 an IPv6 address.
AAAA obsolete format of IPv6 address
CNAME identifies the canonical name of an alias.
DNAME delegates reverse addresses. Replaces the domain name specified with another name to be
looked up. Described in RFC 2672.
HINFO identifies the CPU and OS used by a host.
KEY stores a public key associated with a DNS name.
MX identifies a mail exchange for the domain. See RFC 974 for details.
NS the authoritative nameserver for the domain.
NXT used in DNSSEC to securely indicate that RRs with an owner name in a certain name interval
do not exist in a zone and indicate what RR types are present for an existing name. See RFC
2535 for details.
PTR a pointer to another part of the domain name space.
SIG( signature")"
contains data authenticated in the secure DNS. See RFC 2535 for details.
SOA identifies the start of a zone of authority.
SRV information about well known network services (replaces WKS).
The following classes of resource records are currently valid in the DNS:
IN the Internet system.
RDATA is the type-dependent or class-dependent data that describes the resource:
A for the IN class, a 32 bit IP address.
A6 maps a domain name to an IPv6 address, with a provision for indirection for leading "prefix"
bits.
CNAME a domain name.
DNAME provides alternate naming to an entire subtree of the domain name space, rather than to a sin-
gle node. It causes some suffix of a queried name to be substituted with a name from the
DNAME record’s RDATA.
MX a 16-bit preference value (lower is better) followed by a host name willing to act as a mail
exchange for the owner domain.
Section 4−−198 Hewlett-Packard Company − 23 − HP-UX 11i Version 2: September 2004