Bind 9 Administrator Reference Manual

Chapter 6. BIND 9 Configuration Reference
LOC (x) for storing GPS info. See RFC 1876. Experimental.
MX identifies a mail exchange for the domain. See RFC 974 for
details.
NAPTR name authority pointer.
NSAP a network service access point.
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.
PX provides mappings between RFC 822 and X.400 addresses.
RP (x) information on persons responsible for the domain.
Experimental.
RT (x) route-through binding for hosts that do not have their own
direct wide area network addresses. Experimental.
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).
TXT text records.
WKS (h) information about which well known network services,
such as SMTP, that a domain supports. Historical, replaced by
newer RR SRV.
X25 (x) representation of X.25 network addresses. Experimental.
The following classes of resource records are currently valid in the DNS:
IN the Internet system.
For information about other, older classes of RRs, see Section A.2.1.
RDATA is the type-dependent or class-dependent data that describes the resource:
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