Domain Name System (DNS) Parameters (last updated 2009-07-16) Registries included below: - DNS CLASSes - Resource Record (RR) TYPEs - DNS OpCodes - DNS RCODEs - AFSDB RR Subtype - DHCID RR Identifier Type Codes - DNS Label types - DNS EDNS0 Options - DNS Header Flags - EDNS Header Flags (16 bits) - EDNS Version Numbers (8 bits) Registry Name: DNS CLASSes Reference: [RFC5395] Range Decimal Hexadecimal Registration Procedures Notes ------------- ----------------------------- ---------------------- 0 Standards Action 0x0000 1-127 IETF Review data CLASSes only 0x000-0x007F 128-253 IETF Review QCLASSes and meta-CLASSes only 0x0080-0x00FD 256-32767 IETF Review 0x0100-0x7FFF 32768-57343 Specification Required data CLASSes only 0x8000-0xDFFF 57344-65279 Specification Required QCLASSes and meta-CLASSes only 0xE000-0xFEFF 65280-65534 Reserved for Private Use 0xFF00-0xFFFE 65535 Standards Action 0xFFFF Registry: Decimal Hexadecimal Name Reference ------------- ------------------------------ --------- 0 Reserved [RFC5395] 0x0000 1 Internet (IN) [RFC1035] 0x0001 2 Unassigned 0x0002 3 Chaos (CH) [Moon1981] 0x0003 4 Hesiod (HS) [Dyer1987] 0x0004 5-253 Unassigned 0x0005-0x00FD 254 QCLASS NONE [RFC2136] 0x00FD 255 QCLASS * (ANY) [RFC1035] 0x00FF 256-65279 Unassigned 0x0100-0xFEFF 65280-65534 Reserved for Private Use [RFC5395] 0xFF00-0xFFFE 65535 Reserved [RFC5395] 0xFFFF Registry Name: Resource Record (RR) TYPEs Reference: [RFC5395][RFC1035] Range Decimal Hexadecimal Registration Procedures Notes ------------- -------------------------------------------------------------- -------------- 0 RRTYPE zero is used as a special indicator for the SIG RR 0x0000 [RFC2931], [RFC4034] and in other circumstances and must never be allocated for ordinary use. 1-127 DNS RRTYPE Allocation Policy data TYPEs 0x0001-0x007F 128-255 DNS RRTYPE Allocation Policy Q TYPEs, Meta TYPEs 0x0080-0x00FF 256-61439 DNS RRTYPE Allocation Policy data RRTYPEs 0x0100-0xEFFF 61440-65279 IETF Review 0xF000-0xFEFF 65280-65534 Reserved for Private Use 0xFF00-0xFFFE 65535 Reserved (Standards Action) 0xFFFF Registry: TYPE Value and meaning Reference ----------- --------------------------------------------- --------- A 1 a host address [RFC1035] NS 2 an authoritative name server [RFC1035] MD 3 a mail destination (Obsolete - use MX) [RFC1035] MF 4 a mail forwarder (Obsolete - use MX) [RFC1035] CNAME 5 the canonical name for an alias [RFC1035] SOA 6 marks the start of a zone of authority [RFC1035] MB 7 a mailbox domain name (EXPERIMENTAL) [RFC1035] MG 8 a mail group member (EXPERIMENTAL) [RFC1035] MR 9 a mail rename domain name (EXPERIMENTAL) [RFC1035] NULL 10 a null RR (EXPERIMENTAL) [RFC1035] WKS 11 a well known service description [RFC1035] PTR 12 a domain name pointer [RFC1035] HINFO 13 host information [RFC1035] MINFO 14 mailbox or mail list information [RFC1035] MX 15 mail exchange [RFC1035] TXT 16 text strings [RFC1035] RP 17 for Responsible Person [RFC1183] AFSDB 18 for AFS Data Base location [RFC1183] X25 19 for X.25 PSDN address [RFC1183] ISDN 20 for ISDN address [RFC1183] RT 21 for Route Through [RFC1183] NSAP 22 for NSAP address, NSAP style A record [RFC1706] NSAP-PTR 23 for domain name pointer, NSAP style [RFC1348] SIG 24 for security signature [RFC4034][RFC3755][RFC2535] KEY 25 for security key [RFC4034][RFC3755][RFC2535] PX 26 X.400 mail mapping information [RFC2163] GPOS 27 Geographical Position [RFC1712] AAAA 28 IP6 Address [RFC3596] LOC 29 Location Information [RFC1876] NXT 30 Next Domain - OBSOLETE [RFC3755][RFC2535] EID 31 Endpoint Identifier [Patton] NIMLOC 32 Nimrod Locator [Patton] SRV 33 Server Selection [RFC2782] ATMA 34 ATM Address [ATMDOC] NAPTR 35 Naming Authority Pointer [RFC2915][RFC2168] KX 36 Key Exchanger [RFC2230] CERT 37 CERT [RFC4398] A6 38 A6 (Experimental) [RFC3226][RFC2874] DNAME 39 DNAME [RFC2672] SINK 40 SINK [Eastlake] OPT 41 OPT [RFC2671] APL 42 APL [RFC3123] DS 43 Delegation Signer [RFC4034][RFC3658] SSHFP 44 SSH Key Fingerprint [RFC4255] IPSECKEY 45 IPSECKEY [RFC4025] RRSIG 46 RRSIG [RFC4034][RFC3755] NSEC 47 NSEC [RFC4034][RFC3755] DNSKEY 48 DNSKEY [RFC4034][RFC3755] DHCID 49 DHCID [RFC4701] NSEC3 50 NSEC3 [RFC5155] NSEC3PARAM 51 NSEC3PARAM [RFC5155] Unassigned 52-54 HIP 55 Host Identity Protocol [RFC5205] NINFO 56 NINFO [Reid] RKEY 57 RKEY [Reid] Unassigned 58-98 SPF 99 [RFC4408] UINFO 100 [IANA-Reserved] UID 101 [IANA-Reserved] GID 102 [IANA-Reserved] UNSPEC 103 [IANA-Reserved] Unassigned 104-248 TKEY 249 Transaction Key [RFC2930] TSIG 250 Transaction Signature [RFC2845] IXFR 251 incremental transfer [RFC1995] AXFR 252 transfer of an entire zone [RFC1035] MAILB 253 mailbox-related RRs (MB, MG or MR) [RFC1035] MAILA 254 mail agent RRs (Obsolete - see MX) [RFC1035] * 255 A request for all records [RFC1035] Unassigned 256-32767 TA 32768 DNSSEC Trust Authorities [Weiler] 2005-12-13 DLV 32769 DNSSEC Lookaside Validation [RFC4431] Unassigned 32770-65279 Private use 65280-65534 Reserved 65535 Note: In [RFC1002], two types are defined. It is not clear that these are in use, though if so their assignment does conflict with those above. NB 32 NetBIOS general Name Service NBSTAT 33 NetBIOS NODE STATUS Registry Name: DNS OpCodes Reference: [RFC5395][RFC1035] Registration Procedures: Standards Action as modified by [RFC4020] Registry: OpCode Name Reference ------ --------------------------------- --------- 0 Query [RFC1035] 1 IQuery (Inverse Query, Obsolete) [RFC3425] 2 Status [RFC1035] 3 Unassigned 4 Notify [RFC1996] 5 Update [RFC2136] 6-15 Unassigned Registry Name: DNS RCODEs Reference: [RFC5395][RFC1035] Registration Procedures: IETF Review Registry: RCODE Decimal Hexadecimal Name Description Reference ----------- ---------- ----------------------------------- --------- 0 NoError No Error [RFC1035] 1 FormErr Format Error [RFC1035] 2 ServFail Server Failure [RFC1035] 3 NXDomain Non-Existent Domain [RFC1035] 4 NotImp Not Implemented [RFC1035] 5 Refused Query Refused [RFC1035] 6 YXDomain Name Exists when it should not [RFC2136] 7 YXRRSet RR Set Exists when it should not [RFC2136] 8 NXRRSet RR Set that should exist does not [RFC2136] 9 NotAuth Server Not Authoritative for zone [RFC2136] 10 NotZone Name not contained in zone [RFC2136] 11-15 Unassigned 16 BADVERS Bad OPT Version [RFC2671] 16 BADSIG TSIG Signature Failure [RFC2845] 17 BADKEY Key not recognized [RFC2845] 18 BADTIME Signature out of time window [RFC2845] 19 BADMODE Bad TKEY Mode [RFC2930] 20 BADNAME Duplicate key name [RFC2930] 21 BADALG Algorithm not supported [RFC2930] 22 BADTRUNC Bad Truncation [RFC4635] 23-3840 Unassigned 3841-4095 Reserved for Private Use [RFC5395] 4096-65534 Unassigned 65535 Reserved, can be allocated by Standards Action [RFC5395] Registry Name: AFSDB RR Subtype Reference: [RFC5395][RFC1035] Range Decimal Hexadecimal Registration Procedures ------------- -------------------------------------- 0 Standards Action 0x0000 1-65279 IETF Review 0x0001-0xFEFF 65280-65534 Private Use 0xFF00-0xFFFE 65535 Standards Action 0xFFFF Registry: Decimal Hexadecimal Description Reference ------------- ------------------------------------------ --------- 0 Reserved [RFC5395] 0x0000 1 Andrews File Service v3.0 Location Service [RFC1183] 0x0001 2 DCE/NCA root cell directory node [RFC1183] 0x0002 3-65279 Unassigned 0x0003-0xFEFF 65280-65534 Reserved for Private Use [RFC5395] 0xFF00-0xFFFE 65535 Reserved [RFC5395] 0xFFFF Registry Name: DHCID RR Identifier Type Codes Reference: [RFC4701] Registration Procedures: Standards Action Note: Registration rules to be as follows: New DHCID RR type codes are tentatively assigned after the specification for the associated type code, published as an Internet Draft, has received expert review by a designated expert. The final assignment of DHCID RR type codes is through Standards Action, as defined in [RFC2434]. The expert will be Olafur Gudmundsson Registry: Identifier Type Code Identifier Reference -------------------- ------------------------------------------------ --------- 0x0000 The 1-octet 'htype' followed by 'hlen' octets [RFC4701] of 'chaddr' from a DHCPv4 client's DHCPREQUEST. 0x0001 The data octets (i.e., the Type and [RFC4701] Client-Identifier fields) from a DHCPv4 client's Client Identifier option. 0x0002 The client's DUID (i.e., the data octets of a [RFC4701] DHCPv6 client's Client Identifier option or the DUID field from a DHCPv4 client's Client Identifier option). 0x0003-0xfffe Unassigned [RFC4701] 0xffff Reserved [RFC4701] Registry Name: DNS Label types Reference: [RFC5001] Registration Procedures: Standards Action Note: IETF standards action required to allocate new types The top 2 bits of the first byte of an DNS label indicates the type of label. Registry: Value Type Status Reference ---------------- --------------------------------------------------------- ---------------------------- ---------- 0 0 Normal label lower 6 bits is the length of the label Standard [RFC1035] 1 1 Compressed label the lower 6 bits and the 8 bits Standard [RFC1035] from next octet form a pointer to the compression target. 0 1 Extended label type the lower 6 bits of this type Proposed [RFC2671] (section 3) indicate the type of label in use 0 1 0 0 0 0 0 1 Binary Label Experimental not recommended [RFC3364][RFC3363][RFC2673] 0 1 1 1 1 1 1 1 Reserved for future expansion. Proposed [RFC2671] 1 0 Unallocated Registry Name: DNS EDNS0 Options Reference: [RFC5001] Registration Procedures: Specification Required Registry: Value Name Status Reference -------- ---------- ----------- ----------- 0 Reserved [RFC2671] 1 LLQ On-hold [http://files.dns-sd.org/draft-sekar-dns-llq.txt] 2 UL On-hold [http://files.dns-sd.org/draft-sekar-dns-ul.txt] 3 NSID Standard [RFC5001] 4 Reserved [draft-cheshire-edns0-owner-option] 5-65535 Unassigned [RFC2671] Registry Name: DNS Header Flags Reference: [RFC5395][RFC1035] Registration Procedures: Standards Action Note: In DNS query header there is a flag field in the second 16 bit word in query from bit 5 through bit 11 ([RFC1035] section 4.1.1) Registry: Bit Flag Description Reference -------- ---- --------------------- --------- bit 5 AA Authoritative Answer [RFC1035] bit 6 TC Truncated Response [RFC1035] bit 7 RD Recursion Desired [RFC1035] bit 8 RA Recursion Allowed [RFC1035] bit 9 Reserved bit 10 AD Authentic Data [RFC4035] bit 11 CD Checking Disabled [RFC4035] Registry Name: EDNS Header Flags (16 bits) Reference: [RFC2671] Registration Procedures: RFC Required Registry: Bit Flag Description Reference --------- ---- --------------------- ------------------ Bit 0 DO DNSSEC answer OK [RFC4035][RFC3225] Bit 1-15 Reserved Registry Name: EDNS version Number (8 bits) Reference: [RFC2671] Registration Procedures: Standards Action Registry: Range Description Reference -------- ----------------------- --------- 0 EDNS version 0 [RFC2671] 1-255 Unassigned References ---------- [ATMDOC] ATM Forum Technical Committee, "ATM Name System, V2.0", Doc ID: AF-DANS-0152.000, July 2000. Available from http://www.ipmplsforum.org/ftp/pub/approved-specs/af-dans-0152.000.pdf and held in escrow by IANA. [Dyer1987] Dyer, S., and F. Hsu, "Hesiod", Project Athena Technical Plan - Name Service, April 1987. [Moon1981] D. Moon, "Chaosnet", A.I. Memo 628, Massachusetts Institute of Technology Artificial Intelligence Laboratory, June 1981. [RFC1034] Mockapetris, P., "Domain Names - Concepts and Facilities", STD 13, RFC 1034, USC/Information Sciences Institute, November 1987. [RFC1035] Mockapetris, P., "Domain Names - Implementation and Specification", STD 13, RFC 1035, USC/Information Sciences Institute, November 1987. [RFC1183] Everhart, C., Mamakos, L., Ullmann, R., and P. Mockapetris, Editors, "New DNS RR Definitions", RFC 1183, Transarc, University of Maryland, Prime Computer, USC/Information Sciences Institute, October 1990. [RFC1706] Manning, B., and R. Colella, "DNS NSAP Resource Records", RFC 1706, USC/ISI and NIST, October 1994. [RFC1712] Farrell, C., M. Schulze, B. Pleitner, and D. Baldoni, "DNS Encoding of Geographical Location", RFC 1712, Curtin University of Technology, October 1994. [RFC1876] C. Davis, P. Vixie, T. Goodwin, and I. Dickinson, "A Means for Expressing Location Information in the Domain Name System", RFC 1876, January 1996. [RFC1995] Ohta, M., "Incremental Zone Transfer in DNS", RFC 1995, Tokyo Institute of Technology, August 1996. [RFC1996] Vixie, P., "A Mechanism for Prompt Notification of Zone Changes (DNS NOTIFY)", RFC 1996, ISC, August 1996. [RFC2136] Vixie, P., S. Thomson, Y. Rekhter, and J. Bound, "Dynamic Updates in the Domain Name System (DNS UPDATE) Dynamic Updates in the Domain Name System (DNS UPDATE), RFC 2136, ISC, Bellcore, Cisco, DEC, April 1997. [RFC2163] Allocchio, C., "Using the Internet DNS to Distribute MIXER Conformant Global Address Mapping (MCGAM)", RFC 2163, GARR-Italy, July 1977. [RFC2168] R. Danie1, M. Mealling., "Resolution of Uniform Resource Identifiers using the Domain Name System", RFC 2168, Los Alamos National Laboratory, Network Solutions, Inc., June 1997. [RFC2230] Atkinson, R., "Key Exchange Delegation Record for the DNS", RFC 2230, NRL, October 1997. [RFC2535] Eastlake, D., "Domain Name System Security Extensions", RFC 2535, IBM, March 1999. [RFC2671] Vixie, P., "Extension Mechanisms for DNS (EDNS0)", RFC 2671, August 1999. [RFC2782] Gulbrandsen, A., Vixie, P. and L. Esibov, "A DNS RR for Specifying the Location of Services (DNS SRV)", RFC 2782, February 2000. [RFC2845] Vixie, P., Gudmundsson, O., Eastlake, D. and B. Wellington, "Secret Key Transaction Authentication for DNS (TSIG)", May 2000. [RFC2874] Crawford, M., Huitema, C. and S. Thomson, "DNS Extensions to Support IPv6 Address Aggregation and Renumbering", RFC 2874, July 2000. [RFC2915] Mealling, M. and R. Daniel, "The Naming Authority Pointer (NAPTR) DNS Resource Record", RFC 2915, September 2000. [RFC2930] Eastlake, D., "Secret Key Establishment for DNS (TKEY RR)", RFC 2930, September 2000. [RFC2931] D. Eastlake, "DNS Request and Transaction Signatures ( SIG(0)s )", RFC 2931, September 2000. [RFC3123] P. Koch, "A DNS RR Type for Lists of Address Prefixes (APL RR)", RFC 3123, June 2001. [RFC3225] D. Conrad, "Indicating Resolver Support of DNSSEC", RFC 3225, December 2001. [RFC3226] O. Gudmundsson, "DNSSEC and IPv6 A6 aware server/resolver message size requirements", RFC 3226, December 2001. [RFC3425] D. Lawrence, "Obsoleting IQUERY", RFC 3425, November 2002. [RFC3596] S. Thomson, C. Huitema, V. Ksinant, and M. Souissi, "DNS Extensions to Support IP Version 6", RFC 3596, October 2003. [RFC3658] O. Gudmundsson, "Delegation Signer Resource Record", RFC 3658, December 2003. [RFC3755] S. Weiler, "Legacy Resolver Compatibility for Delegation Signer", RFC 3755, May 2004. [RFC4020] K. Kompella, A. Zinin, "Early IANA Allocation of Standards Track Code Points", RFC 4020, February 2005. [RFC4025] M. Richardson, "A Method for Storing IPsec Keying Material in DNS", RFC 4025, March 2005. [RFC4034] R. Arends, R. Austein, M. Larson, D. Massey, and S. Rose, "Resource Records for the DNS Security Extensions", RFC 4034, March 2005. [RFC4035] R. Arends, R. Austein, M. Larson, D. Massey, and S. Rose, "Protocol Modifications for the DNS Security Extensions", RFC 4035, March 2005. [RFC4255] J. Schlyter and W. Griffin, "Using DNS to Securely Publish SSH Key Fingerprints", RFC 4255, January 2006. [RFC4398] S. Josefsson, "Storing Certificates in the Domain Name System (DNS)", RFC 4398, March 2006. [RFC4408] M. Wong and W. Schlitt, "Sender Policy Framework (SPF) for Authorizing Use of Domains in E-MAIL, version 1", RFC 4408, April 2006. [RFC4431] M. Andrews and S. Weiler, "The DNSSEC Lookaside Validation (DLV) DNS Resource Record", RFC 4431, February 2006. [RFC4635] D. Eastlake 3rd, "HMAC SHA TSIG Algorithm Identifiers", RFC 4635, August 2006. [RFC4701] M. Stapp, T. Lemon, A. Gustafsson, "A DNS RR for Encoding DHCP Information (DHCID RR)", RFC 4701, October 2006. [RFC5001] R. Austein, "DNS Name Server Identifier Option (NSID)", RFC 5001, August 2007. [RFC5155] B. Laurie, G. Sisson, R. Arends, D. Blacka, "DNSSEC Hashed Authenticated Denial of Existence", RFC 5155, March 2008. [RFC5205] P. Nikander, J. Laganier, "Host Identity Protocol (HIP) Domain Name System (DNS) Extensions", RFC 5205, April 2008. [RFC5395] D. Eastlake, "Domain Name System (DNS) IANA Considerations", BCP 42, RFC 5395, November 2008. [draft-cheshire-edns0-owner-option] work in progress People -------- [Daniel] Ron Daniel, , June 1997. [Eastlake] Donald E. Eastlake, III , January 1995, November 1997. [IANA] Internet Assigned Numbers Authority, , December 1994. [Mockapetris] Paul Mockapetris, , November 1994. [Otha] Masataka Ohta, , March 1995. [Patton] Michael Patton, , June 1995. [Reid] Jim Reid, , 21 January 2008. [Thomson] Susan Thomson, , August 1995. [Vixie] Paul Vixie, , June 1997. [Weiler] Sam Weiler, , December 2005. Deploying DNSSEC Without a Signed Rott. Technical Report 1999-19, Information Networking Institute, Carnegie Mellon University, April 2004. http://cameo.library.cmu.edu/ http://www.watson.org/~weiler/INI1999-19.pdf []