DNS 记录类型

Resource records

Type	Value (decimal)	Defining RFC	Description	Function
A	1		Address record	Returns a 32-bit address, most commonly used to map to an IP address of the host, but also used for , storing in , etc.
AAAA	28		address record	Returns a 128-bit address, most commonly used to map to an IP address of the host.
AFSDB	18		AFS database record	Location of database servers of an cell. This record is commonly used by AFS clients to contact AFS cells outside their local domain. A subtype of this record is used by the obsolete file system.
APL	42		Address Prefix List	Specify lists of address ranges, e.g. in format, for various address families. Experimental.
	257		Certification Authority Authorization	CA pinning, constraining acceptable CAs for a host/domain
CERT	37		Certificate record	Stores , , , etc.
	5			Alias of one name to another: the DNS lookup will continue by retrying the lookup with the new name.
DHCID	49		DHCP identifier	Used in conjunction with the FQDN option to
DLV	32769		DNSSEC Lookaside Validation record	For publishing trust anchors outside of the DNS delegation chain. Uses the same format as the DS record. describes a way of using these records.
	39		Delegation Name	DNAME creates an alias for a name and all its subnames, unlike CNAME, which aliases only the exact name in its label. Like the CNAME record, the DNS lookup will continue by retrying the lookup with the new name.
DNSKEY	48		DNS Key record	The key record used in . Uses the same format as the KEY record.
DS	43		Delegation signer	The record used to identify the DNSSEC signing key of a delegated zone
	55		Host Identity Protocol	Method of separating the end-point identifier and locator roles of .
IPSECKEY	45		IPsec Key	Key record that can be used with
KEY	25	and	Key record	Used only for SIG(0) () and TKEY (). eliminated their use for application keys and limited their use to DNSSEC. designates DNSKEY as the replacement within DNSSEC. designates IPSECKEY as the replacement for use with IPsec.
KX	36		Key eXchanger record	Used with some cryptographic systems (not including DNSSEC) to identify a key management agent for the associated domain-name. Note that this has nothing to do with DNS Security. It is Informational status, rather than being on the IETF standards-track. It has always had limited deployment, but is still in use.
	29		Location record	Specifies a geographical location associated with a domain name
	15		Mail exchange record	Maps a domain name to a list of for that domain
	35		Naming Authority Pointer	Allows regular expression based rewriting of domain names which can then be used as , further domain names to lookups, etc.
NS	2		Name server record	Delegates a to use the given
NSEC	47		Next-Secure record	Part of DNSSEC—used to prove a name does not exist. Uses the same format as the (obsolete) NXT record.
NSEC3	50		NSEC record version 3	An extension to DNSSEC that allows proof of nonexistence for a name without permitting zonewalking
NSEC3PARAM	51		NSEC3 parameters	Parameter record for use with NSEC3
PTR	12		Pointer record	Pointer to a . Unlike a CNAME, DNS processing does NOT proceed, just the name is returned. The most common use is for implementing , but other uses include such things as .
RRSIG	46		DNSSEC signature	Signature for a DNSSEC-secured record set. Uses the same format as the SIG record.
RP	17		Responsible person	Information about the responsible person(s) for the domain. Usually an email address with the @ replaced by a .
SIG	24		Signature	Signature record used in SIG(0) () and TKEY (). designated RRSIG as the replacement for SIG for use within DNSSEC.
SOA	6	and	Start of [a zone of] authority record	Specifies authoritative information about a , including the primary name server, the email of the domain administrator, the domain serial number, and several timers relating to refreshing the zone.
	99		Sender Policy Framework	Specified as part of the SPF protocol as an alternative to storing SPF data in TXT records, using the same format. It was later found that the majority of SPF deployments lack proper support for this record type, and as of August 2013 it’s considered for obsolescence.
	33		Service locator	Generalized service location record, used for newer protocols instead of creating protocol-specific records such as MX.
SSHFP	44		SSH Public Key Fingerprint	Resource record for publishing SSH public host key fingerprints in the DNS System, in order to aid in verifying the authenticity of the host. defines ECC SSH keys and SHA-256 hashes. See the for details.
TA	32768	N/A	DNSSEC Trust Authorities	Part of a deployment proposal for DNSSEC without a signed DNS root. See the and for details. Uses the same format as the DS record.
	249		Secret key record	A method of providing keying material to be used with that is encrypted under the public key in an accompanying KEY RR.
	52		TLSA certificate association	A record for (DANE). defines "The TLSA DNS resource record is used to associate a TLS server certificate or public key with the domain name where the record is found, thus forming a 'TLSA certificate association'".
	250		Transaction Signature	Can be used to authenticate as coming from an approved client, or to authenticate responses as coming from an approved recursive name server similar to DNSSEC.
TXT	16		Text record	Originally for arbitrary human-readable text in a DNS record. Since the early 1990s, however, this record more often carries machine-readable data, such as specified by , , , , , , etc.

Other types and pseudo resource records

Other types of records simply provide some types of information (for example, an HINFO record gives a description of the type of computer/OS a host uses), or others return data used in experimental features. The "type" field is also used in the protocol for various operations.

Code	Number	Defining RFC	Description	Function
*	255		All cached records	Returns all records of all types known to the name server. If the name server does not have any information on the name, the request will be forwarded on. The records returned may not be complete. For example, if there is both an A and an MX for a name, but the name server has only the A record cached, only the A record will be returned. Sometimes referred to as "ANY", for example in Windows nslookup and Wireshark.
	252		Authoritative Zone Transfer	Transfer entire zone file from the master name server to secondary name servers.
IXFR	251		Incremental Zone Transfer	Requests a zone transfer of the given zone but only differences from a previous serial number. This request may be ignored and a full (AXFR) sent in response if the authoritative server is unable to fulfill the request due to configuration or lack of required deltas.
OPT	41		Option	This is a "pseudo DNS record type" needed to support