DNS Records

Resource records

Code	Number	Defining RFC	Description	Function
A	1	RFC 1035	address record	Returns a 32-bit IPv4 address, most commonly used to map hostnames to an IP address of the host, but also used forDNSBLs, storing subnet masks in RFC 1101, etc.
AAAA	28	RFC 3596	IPv6 address record	Returns a 128-bit IPv6 address, most commonly used to map hostnames to an IP address of the host.
APL	42	RFC 3123	Address Prefix List	Specify lists of address ranges, e.g. in CIDR format, for various address families. Experimental.
CNAME	5	RFC 1035	Canonicalname record	Alias of one name to another: the DNS lookup will continue by retrying the lookup with the new name.
MX	15	RFC 1035	mail exchange record	Maps a domain name to a list of message transfer agents for that domain
NS	2	RFC 1035	name server record	Delegates a DNS zone to use the given authoritative name servers
SOA	6	RFC 1035	start of authority record	Specifies authoritative information about a DNS zone, including the primary name server, the email of the domain administrator, the domain serial number, and several timers relating to refreshing the zone.
SRV	33	RFC 2782	Service locator	Generalized service location record, used for newer protocols instead of creating protocol-specific records such as MX.
TXT	16	RFC 1035	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 RFC 1464, opportunistic encryption, Sender Policy Framework (although this provisional use of TXT records is deprecated in favor of SPF records), DomainKeys, DNS-SD, etc.