DNS各种查询报文类型说明

时间：2010-06-23 来源：lksj

A Address, code 1. Used for storing an IP address (specifically, an IPv4 32-bit address) associated with a domain name. Defined in RFC 1035. A6 IPv6 address, code 38. Relegated to Experimental status by RFC 3363, as AAAA records are now regarded as more generally useful. Defined in RFC 2874. AAAA IPv6 address, code 28. Used for storing an IPv6 128-bit address associated with a domain name. Defined in RFC 3596. AFSDB AFS Data Base location, code 18. Not widely used, rather use SRV records instead. Defined in RFC 1183. CNAME Canonical name for a DNS alias, code 5. Note that if a domain name has a CNAME record associated with it, then it can not have any other record types. In addition, CNAME records should not point to domain names which themselves have associated CNAME records, so CNAME only provides one layer of indirection. Defined in RFC 1035. DNAME DNAME, code 39. A way to provide aliases for a whole domain, not just a single domain name as with CNAME. Defined in RFC 2672. DS Delegation signer, code 43. A major change to the way DNSSEC operates. Defined in RFC 3658. GPOS Geographical position, code 27, obsolete. Defined in RFC 1712. HINFO Host Information, code 13. Not widely used. Defined in RFC 1035. ISDN ISDN address, code 20. Not widely used. Defined in RFC 1183. KEY Public key as used in DNSSEC, code 25. Defined in RFC 2535. See also RFC 3445. KX Key Exchanger, code 36. Defined in RFC 2230. LOC Location information, code 29. Associates a geographical location with a domain name. Defined in RFC 1876. MB Mailbox, code 7. Not widely used. Defined in RFC 1035. MD Mail destination, code 3, obsolete. Defined in RFC 1035. MF Mail forwarder, code 4, obsolete. Defined in RFC 1035. MG Mail group member, code 8. Not widely used. Defined in RFC 1035. MINFO Mailbox or mailing list information, code 14. Defined in RFC 1035. MR Mail rename domain name, code 9. Not widely used. Defined in RFC 1035. MX Mail Exchanger, code 15. Each MX record specifies a domain name (which must have an A record associated with it) and a priority; a list of mail exchangers is then ordered by priority when delivering mail. MX records provide one level of indirection in mapping the domain part of an email address to a list of host names which are meant to receive mail for that domain name. Critical part of the infrastructure used to support SMTP email. Defined in RFC 1035. NAPTR Naming authority pointer, code 35. Used mostly for Internet telephony infrastructure as in RFC 3263. Defined in RFC 3403. NULL Null record, code 10. Not widely used. Defined in RFC 1035. NS Authoritative name server, code 2. Specifies a host name (which must have an A record associated with it), where DNS information can be found about the domain name to which the NS record is attached. NS records are the basic infrastructure on which DNS is built; they stitch together distributed zone files into a directed graph that can be efficiently searched. Defined in RFC 1035. NSAP Network service access point address, code 22. Allows OSI-style NSAPs to be stored in the DNS. Defined in RFC 1706. NSAP-PTR NSAP pointer, code 23, obsolete. Defined in RFC 1348. NXT Next domain, code 30, obsolete. Defined in RFC 2065. PTR Domain name pointer, code 12. Provides a general indirection facility for DNS records. Most often used to provide a way to associate a domain name with an IPv4 address in the IN-ADDR.ARPA domain. Defined in RFC 1035. PX Pointer to X.400/RFC822 mail mapping information. Defined in RFC 2163. RP Responsible person, code 17. Defined in RFC 1183. RT Route through, code 21. Not widely used. Defined in RFC 1183. SIG Cryptographic public key signature, code 24. Defined in RFC 2931. SOA Start of authority, code 6. Marks the start of a zone. Defined in RFC 1035. SRV Server selection, code 33. Similar to MX records, generalised to any network service. Defined in RFC 2782. TKEY Transaction key, code 249. A way of distributing keys for TSIG records. Defined in RFC 2930. TSIG Transaction signature, code 250. Simple authentication for DNS transactions, using shared secret keys and hashing. Defined in RFC 2845. TXT Text string, code 16. Arbitrary binary data, up to 255 bytes in length. Defined in RFC 1035. WKS Well-known service, code 11. Information about which services are available at a host. Defined in RFC 1035. X25 X25 PSDN address, code 19. Not widely used. Defined in RFC 1183.