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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Transport Area Working Group M. Cotton 3 Internet-Draft ICANN 4 Updates: 2780, 2782, 3828, 4340, L. Eggert 5 4960 (if approved) Nokia 6 Intended status: BCP J. Touch 7 Expires: November 22, 2010 USC/ISI 8 M. Westerlund 9 Ericsson 10 May 21, 2010 12 Internet Assigned Numbers Authority (IANA) Procedures for the Management 13 of the Transport Protocol Port Number and Service Name Registry 14 draft-ietf-tsvwg-iana-ports-05 16 Abstract 18 This document defines the procedures that the Internet Assigned 19 Numbers Authority (IANA) uses when handling registration and other 20 requests related to the transport protocol port number and service 21 name registry. It also discusses the rationale and principles behind 22 these procedures and how they facilitate the long-term sustainability 23 of the registry. 25 This document updates IANA's procedures by obsoleting Sections 8 and 26 9.1 of the IANA allocation guidelines [RFC2780], it updates the IANA 27 allocation procedures for UDP-Lite [RFC3828], DCCP [RFC4340] and SCTP 28 [RFC4960], it updates the DNS SRV specification [RFC2782] to clarify 29 what a service name is and how it is registered. 31 Status of this Memo 33 This Internet-Draft is submitted in full conformance with the 34 provisions of BCP 78 and BCP 79. 36 Internet-Drafts are working documents of the Internet Engineering 37 Task Force (IETF). Note that other groups may also distribute 38 working documents as Internet-Drafts. The list of current Internet- 39 Drafts is at http://datatracker.ietf.org/drafts/current/. 41 Internet-Drafts are draft documents valid for a maximum of six months 42 and may be updated, replaced, or obsoleted by other documents at any 43 time. It is inappropriate to use Internet-Drafts as reference 44 material or to cite them other than as "work in progress." 46 This Internet-Draft will expire on November 22, 2010. 48 Copyright Notice 49 Copyright (c) 2010 IETF Trust and the persons identified as the 50 document authors. All rights reserved. 52 This document is subject to BCP 78 and the IETF Trust's Legal 53 Provisions Relating to IETF Documents 54 (http://trustee.ietf.org/license-info) in effect on the date of 55 publication of this document. Please review these documents 56 carefully, as they describe your rights and restrictions with respect 57 to this document. Code Components extracted from this document must 58 include Simplified BSD License text as described in Section 4.e of 59 the Trust Legal Provisions and are provided without warranty as 60 described in the Simplified BSD License. 62 This document may contain material from IETF Documents or IETF 63 Contributions published or made publicly available before November 64 10, 2008. The person(s) controlling the copyright in some of this 65 material may not have granted the IETF Trust the right to allow 66 modifications of such material outside the IETF Standards Process. 67 Without obtaining an adequate license from the person(s) controlling 68 the copyright in such materials, this document may not be modified 69 outside the IETF Standards Process, and derivative works of it may 70 not be created outside the IETF Standards Process, except to format 71 it for publication as an RFC or to translate it into languages other 72 than English. 74 Table of Contents 76 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 77 2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 78 3. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 6 79 4. Conventions Used in this Document . . . . . . . . . . . . . . 7 80 5. Service Names . . . . . . . . . . . . . . . . . . . . . . . . 8 81 5.1. Service Name Syntax . . . . . . . . . . . . . . . . . . . 9 82 5.2. Service Name Usage in DNS SRV Records . . . . . . . . . . 9 83 6. Port Number Ranges . . . . . . . . . . . . . . . . . . . . . . 10 84 6.1. Port Numbers and Service Names for Experimentation . . . . 11 85 7. Principles for Port Number and Service Name Registry 86 Management . . . . . . . . . . . . . . . . . . . . . . . . . . 11 87 7.1. Past Principles . . . . . . . . . . . . . . . . . . . . . 12 88 7.2. Updated Principles . . . . . . . . . . . . . . . . . . . . 12 89 7.3. Variances for Specific Port Number Ranges . . . . . . . . 15 90 8. IANA Procedures for Managing the Port Number and Service 91 Name Registry . . . . . . . . . . . . . . . . . . . . . . . . 16 92 8.1. Port Number and Service Name Registration . . . . . . . . 16 93 8.2. Port Number and Service Name De-Registration . . . . . . . 19 94 8.3. Port Number and Service Name Re-Use . . . . . . . . . . . 19 95 8.4. Port Number and Service Name Revocation . . . . . . . . . 20 96 8.5. Port Number and Service Name Transfers . . . . . . . . . . 21 97 8.6. Maintenance Issues . . . . . . . . . . . . . . . . . . . . 21 98 9. Security Considerations . . . . . . . . . . . . . . . . . . . 21 99 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 100 10.1. Service Name Consistency . . . . . . . . . . . . . . . . . 22 101 10.2. Port Numbers for SCTP and DCCP Experimentation . . . . . . 24 102 10.3. Updates to DCCP Registries . . . . . . . . . . . . . . . . 25 103 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 26 104 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26 105 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 106 13.1. Normative References . . . . . . . . . . . . . . . . . . . 27 107 13.2. Informative References . . . . . . . . . . . . . . . . . . 28 108 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29 110 1. Introduction 112 For many years, the allocation and registration of new port number 113 values and service names for use with the Transmission Control 114 Protocol (TCP) [RFC0793] and the User Datagram Protocol (UDP) 115 [RFC0768] have had less than clear guidelines. New transport 116 protocols have been added - the Stream Control Transmission Protocol 117 (SCTP) [RFC4960] and the Datagram Congestion Control Protocol (DCCP) 118 [RFC4342] - and new mechanisms like DNS SRV records [RFC2782] have 119 been developed, each with separate registries and separate 120 guidelines. The community recognized the need for additional 121 procedures beyond just assignment; notably modification, revocation, 122 and release. 124 A key factor of this procedural streamlining is to establish 125 identical registration procedures for all IETF transport protocols. 126 This document brings the IANA procedures for TCP and UDP in line with 127 those for SCTP and DCCP, resulting in a single process that 128 requesters and IANA follow for all requests for all transport 129 protocols, including those not yet defined. 131 In addition to detailing the IANA procedures for the initial 132 assignment of port numbers and service names, this document also 133 specifies post-assignment procedures that until now have been handled 134 in an ad hoc manner. These include procedures to de-register a port 135 number that is no longer in use, to re-use a port number allocated 136 for one application that is no longer in use for another application, 137 and the procedure by which IANA can unilaterally revoke a prior port 138 number registration. Section 8 discusses the specifics of these 139 procedures and processes that requesters and IANA follow for all 140 requests for all current and future transport protocols. 142 It is important to note that ownership of registered port numbers and 143 service names remains with IANA. For protocols developed by IETF 144 working groups, IANA now also offers a method for the "early" 145 assignment of port numbers and service names [RFC4020], as described 146 in Section 8.1. 148 This document updates IANA's procedures for UDP and TCP port numbers 149 by obsoleting Sections 8 and 9.1 of the IANA allocation guidelines 150 [RFC2780]. (Note that different sections of the IANA allocation 151 guidelines, relating to the protocol field values in IPv4 header, 152 were also updated in February 2008 [RFC5237].) This document also 153 updates the IANA allocation procedures for DCCP [RFC4340] and SCTP 154 [RFC4960]. 156 The Lightweight User Datagram Protocol (UDP-Lite) [RFC5237] shares 157 the port space with UDP. The UDP-Lite specification says: "UDP-Lite 158 uses the same set of port number values assigned by the IANA for use 159 by UDP". Thus the update of UDP procedures result in an update also 160 of the UDP-Lite procedures. 162 This document also clarify what a service name is and how it is 163 registered. This will impact the DNS SRV specification, because that 164 specification merely makes a brief mention that the symbolic names of 165 services are defined in "Assigned Numbers" [RFC1700], without stating 166 to which section of that 230-page document it refers. The DNS SRV 167 specification may have been referring to the list of Port Assignments 168 (known as /etc/services on Unix), or to the "Protocol And Service 169 Names" section, or to both, or to some other section. Furthermore, 170 "Assigned Numbers" is now obsolete [RFC3232] and has now been 171 replaced by on-line registries [PORTREG][PROTSERVREG]. There are 172 additional updates and clarifications on how DNS SRV utilize the 173 Service name registry created in this document in "Clarification of 174 DNS SRV Owner Names" [I-D.gudmundsson-dnsext-srv-clarify]. 176 The development of new transport protocols is a major effort that the 177 IETF does not undertake very often. If a new transport protocol is 178 standardized in the future, for the purpose of uniformity it is 179 expected to follow as much as possible the guidelines and practices 180 around using port numbers and service names. 182 2. Motivation 184 Information about the registration procedures for the port registry 185 has existed in three locations: the forms for requesting port number 186 registrations on the IANA web site [SYSFORM] [USRFORM], an 187 introductory text section in the file listing the port number 188 registrations themselves [PORTREG], and two brief sections of the 189 IANA Allocation Guidelines [RFC2780]. 191 Similarly, the procedures surrounding service names have been 192 historically unclear. Service names were originally created as 193 mnemonic identifiers for port numbers without a well-defined syntax, 194 beyond the 14-character limit mentioned on the IANA website [SYSFORM] 195 [USRFORM]. Even that length limit has not been consistently applied, 196 and some assigned service names are 15 characters long. When service 197 identification via DNS SRV RRs was introduced, the requirement by 198 IANA to only assign service names and port numbers in combination, 199 led to the creation of an ad hoc service name registry outside of the 200 control of IANA [SRVREG]. 202 This document aggregates all this scattered information into a single 203 reference that aligns and clearly defines the management procedures 204 for both port numbers and service names. It gives more detailed 205 guidance to prospective requesters of ports and service names than 206 the existing documentation, and it streamlines the IANA procedures 207 for the management of the registry, so that management requests can 208 complete in a timely manner. 210 This document defines rules for registration of service names without 211 associated port numbers, for such usages as DNS SRV records 212 [RFC2782], which was not possible under the previous IANA procedures. 213 The document also merges service name registrations from the non-IANA 214 ad hoc registry [SRVREG] and from the IANA "Protocol and Service 215 Names" registry [PROTSERVREG] into the IANA "Port and Service Name" 216 registry [PORTREG], which from here on is the single authoritative 217 registry for service names and port numbers. 219 An additional purpose of this document is to describe the principles 220 that guide the IETF and IANA in their role as the long-term joint 221 stewards of the port number registry. TCP and UDP have been a 222 remarkable success over the last decades. Thousands of applications 223 and application-level protocols have registered ports and service 224 names for their use, and there is every reason to believe that this 225 trend will continue into the future. It is hence extremely important 226 that management of the registry follow principles that ensure its 227 long-term usefulness as a shared resource. Section 7 discusses these 228 principles in detail. 230 3. Background 232 The Transmission Control Protocol (TCP) [RFC0793] and the User 233 Datagram Protocol (UDP) [RFC0768] have enjoyed a remarkable success 234 over the decades as the two most widely used transport protocols on 235 the Internet. They have relied on the concept of "ports" as logical 236 entities for Internet communication. Ports serve two purposes: 237 first, they provide a demultiplexing identifier to differentiate 238 transport sessions between the same pair of endpoints, and second, 239 they may also identify the application protocol and associated 240 service to which processes bind. Newer transport protocols, such as 241 the Stream Control Transmission Protocol (SCTP) [RFC4960] and the 242 Datagram Congestion Control Protocol (DCCP) [RFC4342] have adopted 243 the concept of ports for their communication sessions and use 16-bit 244 port numbers in the same way as TCP and UDP (and UDP-Lite [RFC3828], 245 a variant of UDP). 247 Port numbers are the original and most widely used means for 248 application and service identification on the Internet. Ports are 249 16-bit numbers, and the combination of source and destination port 250 numbers together with the IP addresses of the communicating end 251 systems uniquely identifies a session of a given transport protocol. 253 Port numbers are also known by their corresponding service names such 254 as "telnet" for port number 23 and "http" (and the "www" alias) for 255 port number 80. 257 Hosts running services, hosts accessing services on other hosts, and 258 intermediate devices (such as firewalls and NATs) that restrict 259 services need to agree on which service corresponds to a particular 260 destination port. Although this is ultimately a local decision with 261 meaning only between the endpoints of a connection, it is common for 262 many services to have a default port upon which those servers usually 263 listen, when possible, and these ports are recorded by the Internet 264 Assigned Numbers Authority (IANA) through the port number registry 265 [PORTREG]. 267 Over time, the assumption that a particular port number necessarily 268 implies a particular service may become less true. For example, 269 multiple instances of the same service on the same host cannot 270 generally listen on the same port, and multiple hosts behind the same 271 NAT gateway cannot all have a mapping for the same port on the 272 external side of the NAT gateway, whether using static port mappings 273 configured by hand by the user, or dynamic port mappings configured 274 automatically using a port mapping protocol NAT Port Mapping Protocol 275 (NAT-PMP) [I-D.cheshire-nat-pmp] or Internet Gateway Device (IGD) 276 [IGD]. 278 Applications either use numeric port numbers directly, look up port 279 numbers based on service names via system calls such as 280 getservbyname() on UNIX, look up port numbers by performing queries 281 for DNS SRV records [RFC2782][I-D.cheshire-dnsext-dns-sd] or 282 determine port numbers in a variety of other ways like the TCP Port 283 Service Multiplexer (TCPMUX) [RFC1078]. 285 Designers of applications and application-level protocols may apply 286 to IANA for an assigned port number and service name for a specific 287 application, and may - after successful registration - assume that no 288 other application will use that port number or service name for its 289 communication sessions. Alternatively, application designers may 290 also ask for only an assigned service name, if their application does 291 not require a fixed port number. The latter alternative is 292 encouraged when possible, in order to conserve the more limited port 293 number space. This includes, for example, applications that use DNS 294 SRV records to look up port numbers at runtime. 296 4. Conventions Used in this Document 298 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 299 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 300 document are to be interpreted as described in [RFC2119]. 302 5. Service Names 304 Service names are the unique key in the Port and Service Name 305 registry. This unique symbolic name for a service may also be used 306 for other purposes, such as in DNS SRV records [RFC2782]. Within the 307 registry, this unique key ensures that different services can be 308 unambiguously distinguished, thus preventing name collisions and 309 avoiding confusion about who is the administrative contact for a 310 particular entry. 312 For each service name, there may exist zero or more associated port 313 number assignments. A port number assignment associated with a 314 service name contains the transport protocol, port number and 315 possibly additional data, such as a DCCP Service Code. 317 There may be more than one service name associated with a particular 318 transport protocol and port. There are two valid reasons for 319 allowing service name aliases: 321 o Aliases are permissible when all such service names are for the 322 same service, such as with "http" and "www", which both name TCP 323 port 80. In such cases, one of the service names SHOULD be 324 designated primary, for use with mechanisms such as DNS SRV 325 Records [RFC2782], and the others SHOULD be designated as aliases 326 of the primary service name. This is necessary so that clients 327 and servers using a service discovery mechanism use a consistent 328 name by which to refer to a given service. Otherwise, if a server 329 were to advertise that it supports the "www" service, and a client 330 were to seek instances of the "http" service, that client would 331 fail to discover that server, defeating the purpose of having a 332 service discovery mechanism. For aliases that do not indicate a 333 primary alias, a server is expected to register itself under all 334 aliased service names. 336 o Aliases are also permissible when one service is an extension of 337 another service, and an in-band mechanisms exists for determining 338 if the extension is present or not. One example is port 3478, 339 which has the service name aliases "stun" and "turn". TURN 340 [RFC5766] is an extension to the STUN [RFC5389] service. TURN- 341 enabled clients wishing to locate TURN servers could attempt to 342 discover "stun" services and then checking in-band if the server 343 supports TURN, but this is inefficient. Enabling them to directly 344 query for "turn" servers by name is a better approach. (Note that 345 TURN servers in this case should also be locatable via a "stun" 346 discovery, because every TURN server is also a STUN server.) 348 Service names are assigned on a "first come, first served" basis, as 349 described in Section 8.1. Names should be brief and informative, 350 avoiding words or abbreviations that are redundant in the context of 351 the registry (e.g., "port", "service", "protocol", etc.) Names 352 referring to discovery services, e.g., using multicast or broadcast 353 to identify endpoints capable of a given service, SHOULD use an 354 easily identifiable suffix (e.g., "-disc"). 356 5.1. Service Name Syntax 358 Valid service names MUST contain only these US-ASCII [ANSI.X3-4.1986] 359 characters: letters from A to Z and a to z, digits from 0 to 9, and 360 hyphens ("-", ASCII 0x2D or decimal 45). They MUST be at least one 361 character and no more than fifteen characters long, MUST NOT begin or 362 end with a hyphen, and MUST NOT consist of only digits (in order to 363 be distinguishable from port numbers, which are typically written as 364 all digits). 366 The service name syntax MAY be used to validate a service name 367 string, but MUST NOT be used for any other purpose (e.g., 368 delineation). Any system that includes a service name inside a 369 longer string is itself responsible for delineating the service name. 370 Such systems MUST NOT rely on the syntax of a service name alone for 371 such delineation. 373 The syntax defined in ABNF [RFC5234]: 375 SRVNAME = (ALPHA / *([HYPHEN] ALNUM)) / 376 (1*DIGIT ((HYPHEN ALNUM) / ALPHA) *([HYPHEN] ALNUM)) 377 ALNUM = ALPHA / DIGIT ; A-Z, a-z, 0-9 378 HYPHEN = %x2d ; "-" 379 ALPHA = 380 DIGIT = 382 5.2. Service Name Usage in DNS SRV Records 384 The DNS SRV specification [RFC2782] requests that the Service Label 385 part of the owner name of DNS SRV records includes a "Service" 386 element, defined to be "the symbolic name of the desired service", 387 but did not state precisely which part of the IANA database (i.e. 388 STD 2 when [RFC2782] was written) serves as a registry for standard 389 service names. 391 This document clarifies that the Service Label MUST be a service name 392 as defined herein. The service name SHOULD be registered with IANA 393 and recorded in the Service Names and Port Numbers registry 394 [PORTREG]. This is needed to ensure that only a single registry of 395 Service Names exists and name collisions can be avoided in the 396 future. 398 The details of the use of Service Names from [PORTREG] in SRV Service 399 Labels are specified in [RFC2782] and the documents updating or 400 replacing that specification (see the companion document 401 [I-D.gudmundsson-dnsext-srv-clarify] for more information). 403 The details of how applications make use of DNS SRV should be 404 specified in the documentation set of the application/service. In 405 the absence of such specification, prospective clients of a given 406 service should not assume the existence of SRV RRs for this service 407 or, if they have indications that this will be the case (e.g., by 408 configuration), must assume the unextended naming scheme from 409 [RFC2782] for service discovery with DNS SRV, i.e., the Service Label 410 is constructed from the Service Name registered in [PORTREG] by 411 prepending a single underscore character ("_"). 413 6. Port Number Ranges 415 TCP, UDP, UDP-Lite, SCTP and DCCP use 16-bit namespaces for their 416 port number registries. The port registries for all these transport 417 protocols are subdivided into three ranges of numbers, and 418 Section 7.3 describes the IANA procedures for each range in detail: 420 o the Well Known Ports, also known as the System Ports, from 0-1023 421 (assigned by IANA) 423 o the Registered Ports, also known as the User Ports, from 1024- 424 49151 (assigned by IANA) 426 o the Dynamic Ports, also known as the Private Ports, from 49152- 427 65535 (never assigned) 429 Of the assignable port ranges (Well Known and Registered, i.e., port 430 numbers 0-49151), individual port numbers are in one of three states 431 at any given time: 433 o Assigned: Assigned port numbers are currently allocated to the 434 service indicated in the registry. 436 o Unassigned: Unassigned port numbers are currently available for 437 assignment upon request, as per the procedures outlined in this 438 document. 440 o Reserved: Reserved port numbers are not available for regular 441 assignment; they are "assigned to IANA" for special purposes. 443 Reserved port numbers include values at the edges of each range, 444 e.g., 0, 1023, 1024, etc., which may be used to extend these 445 ranges or the overall port number space in the future. 447 In order to keep the size of the registry manageable, IANA typically 448 only records the Assigned and Reserved port numbers and service names 449 in the registry. Unassigned values are typically not explicitly 450 listed. 452 As a data point, when this document was written, approximately 76% of 453 the TCP and UDP Well Known Ports were assigned, and approximately 9% 454 of the Registered Ports were assigned. (As noted, Dynamic Ports are 455 never assigned.) 457 6.1. Port Numbers and Service Names for Experimentation 459 Of the Well Known ports, two TCP and UDP port numbers (1021 and 460 1022), together with their respective service names ("exp1" and 461 "exp2"), have been assigned for experimentation with new applications 462 and application-layer protocols that require a port number in the 463 assigned ports ranges [RFC4727]. 465 Please refer to Sections 1 and 1.1 of "Assigning Experimental and 466 Testing Numbers Considered Useful" [RFC3692] for how these 467 experimental port numbers are to be used. 469 This document registers the same two port numbers and service names 470 for experimentation with new application-layer protocols over SCTP 471 and DCCP in Section 10.2. 473 Unfortunately, it can be difficult to limit access to these ports. 474 Users SHOULD take measures to ensure that experimental ports are 475 connecting to the intended process. For example, users of these 476 experimental ports might include a 64-bit nonce, once on each segment 477 of a message-oriented channel (e.g., UDP), or once at the beginning 478 of a byte-stream (e.g., TCP), which is used to confirm that the port 479 is being used as intended. Such confirmation of intended use is 480 especially important when these ports are associated with privileged 481 (e.g., system or administrator) processes. 483 7. Principles for Port Number and Service Name Registry Management 485 Management procedures for the port number and service name registry 486 include allocation of port numbers and service names upon request, as 487 well as coordination of information about existing allocations. The 488 latter includes maintaining contact and description information about 489 assignments, revoking abandoned assignments, and redefining 490 assignments when needed. Of these procedures, port number allocation 491 is most critical, in order to continue to conserve the remaining port 492 numbers. 494 As noted earlier, only ~9% of the Registered Port space is currently 495 assigned. The current rate of assignment is approximately 400 ports/ 496 year, and has remained linear for the past 8 years. At that rate, if 497 similar conservation continues, this resource will sustain another 85 498 years of assignment - without the need to resort to reassignment of 499 released values or revocation. Note that the namespace available for 500 service names is even larger, which allows for a simpler management 501 procedures. 503 7.1. Past Principles 505 Before the publication of this document, the principles of port 506 number and service name management followed a few mostly-undocumented 507 guidelines. They are recorded here for historical purposes, and this 508 document updates them in Section 7.2. These principles were: 510 o TCP and UDP ports were simultaneously allocated when either was 511 requested 513 o Port numbers were the primary allocation; service names were 514 informative only, and did not have a well-defined syntax 516 o Port numbers were conserved informally, and sometimes 517 inconsistently (e.g., some services were allocated ranges of many 518 port numbers even where not strictly necessary) 520 o SCTP and DCCP port number and service name registries were managed 521 separately from the TCP/UDP registries 523 o Service names could not be assigned in the ports registry without 524 assigning a corresponding port number at the same time 526 This document clarifies and aligns these guidelines in order to more 527 conservatively manage the limited remaining port number space and to 528 enable and promote the use of service names for service 529 identification without associated port numbers, where possible. 531 7.2. Updated Principles 533 This section summarizes the basic principles by which IANA handles 534 the Port and Service Name registry, and attempts to conserve the port 535 number space. This description is intended to inform applicants 536 requesting service names and port numbers. IANA decisions are not 537 required to be bound to these principles, however; other factors may 538 come into play, and exceptions may occur where deemed in the best 539 interest of the Internet. 541 IANA will begin assigning service names that do not request a 542 corresponding port number allocation under a simple "First Come, 543 First Served" policy [RFC5226]. IANA MAY, at its discretion, refer 544 service name requests to "Expert Review" in cases of mass 545 registrations or other situations where IANA believes expert review 546 is advisable. 548 The basic principle of port number registry management is to conserve 549 use of the port space where possible. Extensions to support larger 550 port number spaces would require changing many core protocols of the 551 current Internet in a way that would not be backward compatible and 552 interfere with both current and legacy applications. To help ensure 553 this conservation the policy for any registration request for port 554 number allocations uses the "Expert Review" policy [RFC5226]. 556 Conservation of the port number space is required because this space 557 is a limited resource, applications are expected to participate in 558 the traffic demultiplexing process where feasible. The port numbers 559 are expected to encode as little information as possible that will 560 still enable an application to perform further demultiplexing by 561 itself. In particular: 563 o IANA will allocate only one assigned port number per service or 564 application 566 o IANA will allocate only one assigned port number for all versions 567 of a service (e.g., running the service with or without a security 568 mechanism, or for updated variants of a service) 570 o IANA will allocate only one assigned port number for all different 571 types of device using or participating in the same service 573 o IANA will allocate port numbers only for the transport protocol(s) 574 explicitly named in an registration request 576 o IANA may recover unused port numbers, via the new procedures of 577 de-registration, revocation, and transfer 579 A given service is expected to further demultiplex messages where 580 possible. For example, applications and protocols are expected to 581 include in-band version information, so that future versions of the 582 application or protocol can share the same allocated port. 583 Applications and protocols are also expected to be able to 584 efficiently use a single allocated port for multiple sessions, either 585 by demultiplexing multiple streams within one port, or using the 586 allocated port to coordinate using dynamic ports for subsequent 587 exchanges (e.g., in the spirit of FTP [RFC0959]). 589 Ports are used in various ways, notably: 591 o as endpoint process identifiers 593 o as application protocol identifiers 595 o for firewall filtering purposes 597 The process and protocol identifier use suggests that anything a 598 single process can demultiplex, or that can be encoded into a single 599 protocol, should be. The firewall filtering use suggests that some 600 uses that could be multiplexed or encoded must be separated to allow 601 for firewall management. Note that this latter use is much less 602 sound, because port numbers have meaning only for the two endpoints 603 involved in a connection, and drawing conclusions about the service 604 that generated a given flow based on observed port numbers is not 605 always reliable. Further, previous separation of protocol variants 606 based on security capabilities (e.g., HTTP on TCP port 80 vs. HTTPS 607 on TCP port 443) is not recommended for new protocols, because all 608 should be security-capable and capable of negotiating the use of 609 security in-band. 611 IANA will begin assigning port numbers for only those transport 612 protocols explicitly included in a registration request. This ends 613 the long-standing practice of automatically assigning a port number 614 to an application for both TCP and a UDP, even if the request is for 615 only one of these transport protocols. The new allocation procedure 616 conserves resources by allocating a port number to an application for 617 only those transport protocols (TCP, UDP, SCTP and/or DCCP) it 618 actually uses. The port number will be marked as Reserved - instead 619 of Assigned - in the port number registries of the other transport 620 protocols. When applications start supporting the use of some of 621 those additional transport protocols, the administrative contact for 622 the registration MUST request IANA to convert the reservation into a 623 proper assignment. An application MUST NOT assume that it can use a 624 port number assigned to it for use with one transport protocol with 625 another transport protocol without asking IANA to convert the 626 reservation into an assignment. 628 When the available pool of unassigned numbers has run out in a ports 629 range, it will be necessary for IANA to consider the Reserved ports 630 for assignment. This is part of the motivation to not automatically 631 assigning ports for other transport protocols than the requested 632 ones. This will allow more ports to be available for assignment at 633 that point. It also shows the importance to register the transport 634 protocols that are in fact used. 636 Conservation of port numbers is improved by procedures that allow 637 previously allocated port numbers to become Unassigned, either 638 through de-registration or through revocation, and by a procedure 639 that lets application designers transfer an allocated but unused port 640 number to a new application. Section 8 describes these procedures, 641 which so far were undocumented. Port number conservation is also 642 improved by recommending that applications that do not require an 643 allocated port chose this option and register only a service name. 645 7.3. Variances for Specific Port Number Ranges 647 Section 6 describes the different port number ranges. It is 648 important to note that IANA applies slightly different procedures 649 when managing the different ranges of the port number registry: 651 o Ports in the Dynamic Ports range (49152-65535) have been 652 specifically set aside for local and dynamic use and cannot be 653 registered through IANA. Applications may simply use them for 654 communication without any sort of registration. On the other 655 hand, applications MUST NOT assume that a specific port number in 656 the Dynamic Ports range will always be available for communication 657 at all times, and a port number in that range hence MUST NOT be 658 used as a service identifier. 660 o Ports in the Registered Ports range (1024-49151) are available for 661 registration through IANA, and MAY be used as service identifiers 662 upon successful registration. Because registering a port number 663 for a specific application consumes a fraction of the shared 664 resource that is the port number registry, IANA will require the 665 requester to document the intended use of the port number. This 666 documentation will be input to the "Expert Review" allocation 667 procedure [RFC5226], by which IANA will have a technical expert 668 review the request to determine whether to grant the registration. 669 The submitted documentation MUST explain why using a port number 670 in the Dynamic Ports range is unsuitable for the given 671 application. Ports in the Registered Ports range may also be 672 assigned under the "IETF Review" or "IESG Approval" allocation 673 procedures [RFC5226], which is how most assignments for IETF 674 protocols are handled. 676 o Ports in the Well Known Ports range (0-1023) are also available 677 for registration through IANA. Because the Well Known Ports range 678 is both the smallest and the most densely allocated, the 679 requirements for new allocations are more strict than those for 680 the Registered Ports range, and will only be granted under the 681 "IETF Review" or "IESG Approval" allocation procedures [RFC5226]. 683 A request for a Well Known port number MUST document why using a 684 port number from both the Registered Ports and Dynamic Ports 685 ranges is unsuitable for the given application. 687 8. IANA Procedures for Managing the Port Number and Service Name 688 Registry 690 This section describes the process for requests associated with 691 IANA's management of the port number and service name registry. Such 692 requests include initial registration, de-registration, re-use, 693 changes to the service name, as well as updates to the contact 694 information or description associated with an assignment. Revocation 695 is initiated by IANA. 697 8.1. Port Number and Service Name Registration 699 Registration refers to the allocation of port numbers or service 700 names to applicants. All such registrations are made from port 701 numbers or service names that are Unassigned or Reserved at the time 702 of the allocation. Unassigned numbers and names are allocated as 703 needed, and without further explanation. Reserved numbers and names 704 are assigned only after review by IANA and the IETF, and are 705 accompanied by a statement explaining the reason a Reserved number or 706 name is appropriate for this action. 708 When a registration for one or more transport protocols is approved, 709 the port number for any non-requested transport protocol(s) will be 710 marked as Reserved. IANA SHOULD NOT assign that port number to any 711 other application or service until no other port numbers remain 712 Unassigned in the requested range. The current administrative 713 contact for a port number MAY register these Reserved port numbers 714 for other transport protocols when needed. 716 Service names, on the other hand, are not tied to a specific 717 transport protocol, and registration requests for only a service name 718 (but not a port number) allocate that service name for use with all 719 transport protocols. 721 A port number or service name registration request contains some or 722 all of the following information. The combination of service name 723 and transport protocol is the unique identifier of a given service: 725 Service Name (REQUIRED) 726 Transport Protocol(s) (REQUIRED) 727 Registration Administrative Contact (REQUIRED) 728 Registration Technical Contact (REQUIRED) 729 Port Number (OPTIONAL) 730 Service Code (only REQUIRED for DCCP) 731 Description (REQUIRED) 732 Reference (REQUIRED) 733 Known Unauthorized Uses (OPTIONAL) 734 Assignment Notes (OPTIONAL) 736 o Service Name: A desired unique service name for the service 737 associated with the registration request MUST be provided, for use 738 in various service selection and discovery mechanisms (including, 739 but not limited to, DNS SRV records [RFC2782]). The name MUST be 740 compliant with the syntax defined in Section 5.1. In order to be 741 unique, they MUST NOT be identical to any currently registered 742 service names in the IANA registry [PORTREG]. Service names are 743 case-insensitive; they may be provided and entered into the 744 registry with mixed case (e.g., for clarity), but for the purposes 745 of comparison, the case is ignored. 747 o Transport Protocol(s): The transport protocol(s) for which the 748 allocation is requested MUST be provided. This field is currently 749 limited to one or more of TCP, UDP, SCTP, and DCCP. This field is 750 required even for services with no port number. 752 o Registration Administrative Contact: Name and email address of the 753 administrative contact for the registration. This is REQUIRED. 754 The name of the administrative contact identifies the 755 organization, company, or individual who is responsible for the 756 registration. For registrations done through IETF-published RFCs, 757 the administrative contact will be the IESG. 759 o Registration Technical Contact: Name and email address of the 760 technical contact person for the registration. This is REQUIRED. 761 For individuals, this is the same as the Registration 762 Administrative Contact; for organizations, this is a point of 763 contact at that organization. Additional address information MAY 764 be provided. For registrations done through IETF-published RFCs, 765 the technical contact will be the IESG. 767 o Port Number: If assignment of a port number is desired, either the 768 currently Unassigned port number the requester suggests for 769 allocation, or the text "ANY", MUST be provided. If only a 770 service name is to be assigned, this field MUST be empty. If a 771 specific port number is requested, IANA is encouraged to allocate 772 the requested number. If the text "ANY" is specified, IANA will 773 choose a suitable number from the Registered Ports range. Note 774 that the applicant MUST NOT use the requested port prior to the 775 completion of the registration. 777 o Service Code: The request MUST include a desired unique DCCP 778 service code [RFC5595], if the registration request includes DCCP 779 as a transport protocol, and MUST NOT include a requested DCCP 780 service code otherwise. Section 19.8 of [RFC4340] defines 781 requirements and rules for allocation, updated by this document. 783 o Description: A short description of the service associated with 784 the registration request is REQUIRED. It should avoid all but the 785 most well known acronyms. 787 o Reference: A description of (or a reference to a document 788 describing) the protocol or application using this port. The 789 description must include whether the protocol uses either 790 broadcast, multicast, or anycast communication. 792 For registrations requesting only a Service Name or a Service Name 793 and Registered Port, a statement that the protocol is proprietary 794 and not publicly documented is also acceptable provided that the 795 above information regarding use of broadcast, multicast, or 796 anycast is given. 798 For registration requests for a Registered Port, the registration 799 request MUST explain why a port number in the Dynamic Ports range 800 is unsuitable for the given application. 802 For registration requests for a Well Known Port, the registration 803 request MUST explain why a port number in the Registered Ports or 804 Dynamic Ports ranges is unsuitable, and a reference to a stable 805 protocol specification document MUST be provided. For requests 806 from IETF Working Groups, IANA MAY accept "Early" registration 807 requests referencing a sufficiently stable Internet Draft instead 808 of a published Standards-Track RFC [RFC4020]. 810 o Known Unauthorized Uses: A list of uses by applications or 811 organizations who are not the assignee. This list may be 812 augmented by IANA after assignment when unauthorized uses are 813 reported. 815 o Assignment Notes: Indications of owner/name change, or any other 816 assignment process issue. This list may be updated by IANA after 817 assignment to help track changes to an assignment, e.g., de- 818 registration, owner/name changes, etc. 820 If the registration request is for the addition of a new transport 821 protocol to an already assigned service name, IANA needs to confirm 822 with the administrative contact for the existing assignment whether 823 this addition is appropriate. 825 If the registration request is for a service name alias (see 826 Section 5), IANA needs to confirm with the administrative contact for 827 the existing service name whether the registration of the alias is 828 appropriate. 830 When IANA receives a registration request - containing the above 831 information - that is requesting a port number, IANA SHALL initiate 832 an "Expert Review" [RFC5226] in order to determine whether an 833 assignment should be made. For requests that do not include a port 834 number, IANA SHOULD assign the service name under a simple "First 835 Come First Served" policy [RFC5226]. 837 8.2. Port Number and Service Name De-Registration 839 The administrative contact of a granted port number assignment can 840 return the port number to IANA at any time if they no longer have a 841 need for it. The port number will be de-registered and will be 842 marked as Reserved. IANA should not re-assign port numbers that have 843 been de-registered until all other available port numbers in the 844 specific range have been assigned. 846 Before proceeding with a port number de-registration, IANA needs to 847 reasonably establish that the value is actually no longer in use. 849 Because there is much less danger of exhausting the service name 850 space compared to the port number space, it is RECOMMENDED that a 851 given service name remain assigned even after all associated port 852 number assignments have become de-registered. Under this policy, it 853 will appear in the registry as if it had been created through a 854 service name registration request that did not include any port 855 numbers. 857 On rare occasions, it may still be useful to de-register a service 858 name. In such cases, IANA will mark the service name as Reserved. 859 IANA will involve their IESG-appointed expert in such cases. 861 8.3. Port Number and Service Name Re-Use 863 If the administrative contact of a granted port number assignment no 864 longer have a need for the registered number, but would like to re- 865 use it for a different application, they can submit a request to IANA 866 to do so. 868 Logically, port number re-use is to be thought of as a de- 869 registration (Section 8.2) followed by an immediate re-registration 870 (Section 8.1) of the same port number for a new application. 871 Consequently, the information that needs to be provided about the 872 proposed new use of the port number is identical to what would need 873 to be provided for a new port number allocation for the specific 874 ports range. 876 Because there is much less danger of exhausting the service name 877 space compared to the port number space, it is RECOMMENDED that the 878 original service name associated with the prior use of the port 879 number remains assigned, and a new service be created and associated 880 with the port number. This is again consistent with viewing a re-use 881 request as a de-registration followed by an immediate re- 882 registration. Re-using an assigned service name for a different 883 application is NOT RECOMMENDED. 885 IANA needs to carefully review such requests before approving them. 886 In some instances, the Expert Reviewer will determine that the 887 application that the port number was assigned to has found usage 888 beyond the original requester, or that there is a concern that it may 889 have such users. This determination MUST be made quickly. A 890 community call concerning revocation of a port number (see below) MAY 891 be considered, if a broader use of the port number is suspected. 893 8.4. Port Number and Service Name Revocation 895 A port number revocation can be thought of as an IANA-initiated de- 896 registration (Section 8.2), and has exactly the same effect on the 897 registry. 899 Sometimes, it will be clear that a specific port number is no longer 900 in use and that IANA can revoke it and mark it as Reserved. At other 901 times, it may be unclear whether a given assigned port number is 902 still in use somewhere in the Internet. In those cases, IANA must 903 carefully consider the consequences of revoking the port number, and 904 SHOULD only do so if there is an overwhelming need. 906 With the help of their IESG-appointed Expert Reviewer, IANA SHALL 907 formulate a request to the IESG to issue a four-week community call 908 concerning the pending port number revocation. The IESG and IANA, 909 with the Expert Reviewer's support, SHALL determine promptly after 910 the end of the community call whether revocation should proceed and 911 then communicate their decision to the community. This procedure 912 typically involves similar steps to de-registration except that it is 913 initiated by IANA. 915 Because there is much less danger of exhausting the service name 916 space compared to the port number space, revoking service names is 917 NOT RECOMMENDED. 919 8.5. Port Number and Service Name Transfers 921 The value of port numbers and service names is defined by their 922 careful management as a shared Internet resource, whereas enabling 923 transfer allows the potential for associated monetary exchanges. As 924 a result, the IETF does not permit port number or service name 925 assignments to be transferred between parties, even when they are 926 mutually consenting. 928 The appropriate alternate procedure is a coordinated de-registration 929 and registration: The new party requests the port number or service 930 name via a registration and the previous party releases its 931 assignment via the de-registration procedure outlined above. 933 With the help of their IESG-appointed Expert Reviewer, IANA SHALL 934 carefully determine if there is a valid technical, operational or 935 managerial reason to grant the requested new assignment. 937 8.6. Maintenance Issues 939 In addition to the formal procedures described above, updates to the 940 Description and Technical Contact information are coordinated by IANA 941 in an informal manner, and may be initiated by either the registrant 942 or by IANA, e.g., by the latter requesting an update to current 943 contact information. (Note that Registration Administrative Contact 944 cannot be changed; see Section 8.5 above.) 946 9. Security Considerations 948 The IANA guidelines described in this document do not change the 949 security properties of UDP, TCP, SCTP, or DCCP. 951 Assignment of a port number or service name does not in any way imply 952 an endorsement of an application or product, and the fact that 953 network traffic is flowing to or from a registered port number does 954 not mean that it is "good" traffic, or even that it is used by the 955 assigned service. Firewall and system administrators should choose 956 how to configure their systems based on their knowledge of the 957 traffic in question, not whether there is a port number or service 958 name registered or not. 960 Services are expected to include support for security, either as 961 default or dynamically negotiated in-band. The use of separate port 962 number or service name assignments for secure and insecure variants 963 of the same service is to be avoided in order to discourage the 964 deployment of insecure services. 966 10. IANA Considerations 968 This document obsoletes Sections 8 and 9.1 of the March 2000 IANA 969 Allocation Guidelines [RFC2780]. 971 Upon approval of this document, IANA is requested to contact the 972 maintainer of the [SRVREG] registry, in order to merge the contents 973 of that private registry into the official IANA registry. It is 974 expected that the contents of [SRVREG] will at that time be replaced 975 with pointers to the IANA registry and to this RFC. 977 IANA is instructed to create a new service name entry in the port 978 number registry [PORTREG] for any entry in the "Protocol and Service 979 Names" registry [PROTSERVREG] that does not already have one 980 assigned. 982 IANA is also instructed to indicate which service name aliases in the 983 existing registry are the primary aliases (see Section 5). 985 10.1. Service Name Consistency 987 Section 8.1 defines which character strings are well-formed service 988 names, which until now had not been clearly defined. The definition 989 in Section 8.1 was chosen to allow maximum compatibility of service 990 names with current and future service discovery mechanisms. 992 As of August 5, 2009 approximately 98% of the so-called "Short Names" 993 from existing port number registrations [PORTREG] meet the rules for 994 legal service names stated in Section 8.1, and hence will be used 995 unmodified. 997 The remaining approximately 2% of the exiting "Short Names" are not 998 suitable to be used directly as well-formed service names because 999 they contain illegal characters such as asterisks, dots, pluses, 1000 slashes, or underscores. All existing "Short Names" conform to the 1001 length requirement of 15 characters or fewer. For these unsuitable 1002 "Short Names", listed in the table below, the service name will be 1003 the Short Name with any illegal characters replaced by hyphens. IANA 1004 SHALL add an entry to the registry giving the new well-formed primary 1005 service name for the existing service, that otherwise duplicates the 1006 original assignment information. In the description field of this 1007 new entry giving the primary service name, IANA SHALL record that it 1008 assigns a well-formed service name for the previous service and 1009 reference the original assignment. In the description field of the 1010 original assignment, IANA SHALL add a note that this entry is an 1011 alias to the new well-formed service name, and that the old service 1012 name is historic, not usable for use with many common service 1013 discovery mechanisms. 1015 Names containing illegal characters to be replaced by hyphens: 1017 +----------------+-----------------+-----------------+ 1018 | 914c/g | acmaint_dbd | acmaint_transd | 1019 | atex_elmd | avanti_cdp | badm_priv | 1020 | badm_pub | bdir_priv | bdir_pub | 1021 | bmc_ctd_ldap | bmc_patroldb | boks_clntd | 1022 | boks_servc | boks_servm | broker_service | 1023 | bues_service | canit_store | cedros_fds | 1024 | cl/1 | contamac_icm | corel_vncadmin | 1025 | csc_proxy | cvc_hostd | dbcontrol_agent | 1026 | dec_dlm | dl_agent | documentum_s | 1027 | dsmeter_iatc | dsx_monitor | elpro_tunnel | 1028 | elvin_client | elvin_server | encrypted_admin | 1029 | erunbook_agent | erunbook_server | esri_sde | 1030 | EtherNet/IP-1 | EtherNet/IP-2 | event_listener | 1031 | flr_agent | gds_db | ibm_wrless_lan | 1032 | iceedcp_rx | iceedcp_tx | iclcnet_svinfo | 1033 | idig_mux | ife_icorp | instl_bootc | 1034 | instl_boots | intel_rci | interhdl_elmd | 1035 | lan900_remote | LiebDevMgmt_A | LiebDevMgmt_C | 1036 | LiebDevMgmt_DM | mapper-ws_ethd | matrix_vnet | 1037 | mdbs_daemon | menandmice_noh | msl_lmd | 1038 | nburn_id | ncr_ccl | nds_sso | 1039 | netmap_lm | nms_topo_serv | notify_srvr | 1040 | novell-lu6.2 | nuts_bootp | nuts_dem | 1041 | ocs_amu | ocs_cmu | pipe_server | 1042 | pra_elmd | printer_agent | redstorm_diag | 1043 | redstorm_find | redstorm_info | redstorm_join | 1044 | resource_mgr | rmonitor_secure | rsvp_tunnel | 1045 | sai_sentlm | sge_execd | sge_qmaster | 1046 | shiva_confsrvr | sql*net | srvc_registry | 1047 | stm_pproc | subntbcst_tftp | udt_os | 1048 | universe_suite | veritas_pbx | vision_elmd | 1049 | vision_server | wrs_registry | z39.50 | 1050 +----------------+-----------------+-----------------+ 1052 Following the example set by the "application/whoispp-query" MIME 1053 Content-Type [RFC2957], the service name for "whois++" will be 1054 "whoispp". 1056 10.2. Port Numbers for SCTP and DCCP Experimentation 1058 Two Well Known UDP and TCP ports, 1021 and 1022, have been reserved 1059 for experimental use [RFC4727]. This document registers the same 1060 port numbers for SCTP and DCCP, and also instructs IANA to 1061 automatically register these two port numbers for any new transport 1062 protocol that will in the future share the port number namespace. 1064 Note that these port numbers are meant for temporary experimentation 1065 and development in controlled environments. Before using these port 1066 numbers, carefully consider the advice in Section 6.1 in this 1067 document, as well as in Sections 1 and 1.1 of "Assigning Experimental 1068 and Testing Numbers Considered Useful" [RFC3692]. Most importantly, 1069 application developers must request a permanent port number 1070 assignment from IANA as described in Section 8.1 before any kind of 1071 non-experimental deployment. 1073 +-------------------------------------+----------------------------+ 1074 | Registration Administrative Contact | IETF | 1075 | Registration Technical Contact | IESG | 1076 | Service Name | exp1 | 1077 | Port Number | 1021 | 1078 | Transport Protocol | SCTP, DCCP | 1079 | Description | RFC3692-style Experiment 1 | 1080 | Reference | [RFCyyyy] | 1081 +-------------------------------------+----------------------------+ 1083 +-------------------------------------+----------------------------+ 1084 | Registration Administrative Contact | IETF | 1085 | Registration Technical Contact | IESG | 1086 | Service Name | exp2 | 1087 | Port Number | 1022 | 1088 | Transport Protocol | SCTP, DCCP | 1089 | Description | RFC3692-style Experiment 2 | 1090 | Reference | [RFCyyyy] | 1091 +-------------------------------------+----------------------------+ 1093 [RFC Editor Note: Please change "yyyy" to the RFC number allocated to 1094 this document before publication.] 1096 10.3. Updates to DCCP Registries 1098 This document updates the IANA allocation procedures for the DCCP 1099 Port Number and DCCP Service Codes Registries [RFC4340]. 1101 10.3.1. DCCP Service Code Registry 1103 Service Codes are allocated first-come-first-served according to 1104 Section 19.8 of the DCCP specification [RFC4340]. This document 1105 updates that section by extending the guidelines given there in the 1106 following ways: 1108 o IANA MAY assign new Service Codes without seeking Expert Review 1109 using their discretion, but SHOULD seek expert review if a request 1110 seeks more than five Service Codes. 1112 o IANA should feel free to contact the DCCP Expert Reviewer with 1113 questions on any registry, regardless of the registry policy, for 1114 clarification or if there is a problem with a request [RFC4340]. 1116 10.3.2. DCCP Port Numbers Registry 1118 The DCCP ports registry is defined by Section 19.9 of the DCCP 1119 specification [RFC4340]. Allocations in this registry require prior 1120 allocation of a Service Code. Not all Service Codes require IANA- 1121 registered ports. This document updates that section by extending 1122 the guidelines given there in the following way: 1124 o IANA should normally assign a value in the range 1024-49151 to a 1125 DCCP server port. IANA allocation requests to allocate port 1126 numbers in the Well Known Ports range (0 through 1023), require an 1127 "IETF Review" [RFC5226] prior to allocation by IANA [RFC4340]. 1129 o IANA MUST NOT allocate more than one DCCP server port to a single 1130 service code value. 1132 o The allocation of multiple service codes to the same DCCP port is 1133 allowed, but subject to expert review. 1135 o The set of Service Code values associated with a DCCP server port 1136 should be recorded in the ports registry. 1138 o A request for additional Service Codes to be associated with an 1139 already allocated Port Number requires Expert Review. These 1140 requests will normally be accepted when they originate from the 1141 contact associated with the port registration. In other cases, 1142 these applications will be expected to use an unallocated port, 1143 when this is available. 1145 The DCCP specification [RFC4340] notes that a short port name MUST be 1146 associated with each DCCP server port that has been registered. This 1147 document requires that this name MUST be unique. 1149 11. Contributors 1151 Stuart Cheshire (cheshire@apple.com), Alfred Hoenes (ah@tr-sys.de) 1152 and Allison Mankin (mankin@psg.com) have contributed text and ideas 1153 to this document. 1155 12. Acknowledgments 1157 The text in Section 10.3 is based on a suggestion originally proposed 1158 as a part of [RFC5595] by Gorry Fairhurst. 1160 Lars Eggert is partly funded by the Trilogy Project [TRILOGY], a 1161 research project supported by the European Commission under its 1162 Seventh Framework Program. 1164 13. References 1166 13.1. Normative References 1168 [ANSI.X3-4.1986] 1169 American National Standards Institute, "Coded Character 1170 Set - 7-bit American Standard Code for Information 1171 Interchange", ANSI X3.4, 1986. 1173 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, 1174 August 1980. 1176 [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, 1177 RFC 793, September 1981. 1179 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1180 Requirement Levels", BCP 14, RFC 2119, March 1997. 1182 [RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For 1183 Values In the Internet Protocol and Related Headers", 1184 BCP 37, RFC 2780, March 2000. 1186 [RFC3828] Larzon, L-A., Degermark, M., Pink, S., Jonsson, L-E., and 1187 G. Fairhurst, "The Lightweight User Datagram Protocol 1188 (UDP-Lite)", RFC 3828, July 2004. 1190 [RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of 1191 Standards Track Code Points", BCP 100, RFC 4020, 1192 February 2005. 1194 [RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram 1195 Congestion Control Protocol (DCCP)", RFC 4340, March 2006. 1197 [RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, 1198 ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006. 1200 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1201 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1202 May 2008. 1204 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 1205 Specifications: ABNF", STD 68, RFC 5234, January 2008. 1207 13.2. Informative References 1209 [I-D.cheshire-dnsext-dns-sd] 1210 Cheshire, S. and M. Krochmal, "DNS-Based Service 1211 Discovery", draft-cheshire-dnsext-dns-sd-06 (work in 1212 progress), March 2010. 1214 [I-D.cheshire-nat-pmp] 1215 Cheshire, S., "NAT Port Mapping Protocol (NAT-PMP)", 1216 draft-cheshire-nat-pmp-03 (work in progress), April 2008. 1218 [I-D.gudmundsson-dnsext-srv-clarify] 1219 Gudmundsson, O. and A. Hoenes, "Clarification of DNS SRV 1220 Owner Names", draft-gudmundsson-dnsext-srv-clarify-00 1221 (work in progress), December 2009. 1223 [IGD] UPnP Forum, "Internet Gateway Device (IGD) V 1.0", 1224 November 2001. 1226 [PORTREG] Internet Assigned Numbers Authority (IANA), "Port Numbers 1227 Registry", http://www.iana.org/assignments/port-numbers. 1229 [PROTSERVREG] 1230 Internet Assigned Numbers Authority (IANA), "Protocol and 1231 Service Names Registry", 1232 http://www.iana.org/assignments/service-names. 1234 [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", 1235 STD 9, RFC 959, October 1985. 1237 [RFC1078] Lottor, M., "TCP port service Multiplexer (TCPMUX)", 1238 RFC 1078, November 1988. 1240 [RFC1700] Reynolds, J. and J. Postel, "Assigned Numbers", RFC 1700, 1241 October 1994. 1243 [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for 1244 specifying the location of services (DNS SRV)", RFC 2782, 1245 February 2000. 1247 [RFC2957] Daigle, L. and P. Faltstrom, "The application/ 1248 whoispp-query Content-Type", RFC 2957, October 2000. 1250 [RFC3232] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by 1251 an On-line Database", RFC 3232, January 2002. 1253 [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers 1254 Considered Useful", BCP 82, RFC 3692, January 2004. 1256 [RFC4342] Floyd, S., Kohler, E., and J. Padhye, "Profile for 1257 Datagram Congestion Control Protocol (DCCP) Congestion 1258 Control ID 3: TCP-Friendly Rate Control (TFRC)", RFC 4342, 1259 March 2006. 1261 [RFC4960] Stewart, R., "Stream Control Transmission Protocol", 1262 RFC 4960, September 2007. 1264 [RFC5237] Arkko, J. and S. Bradner, "IANA Allocation Guidelines for 1265 the Protocol Field", BCP 37, RFC 5237, February 2008. 1267 [RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing, 1268 "Session Traversal Utilities for NAT (STUN)", RFC 5389, 1269 October 2008. 1271 [RFC5595] Fairhurst, G., "The Datagram Congestion Control Protocol 1272 (DCCP) Service Codes", RFC 5595, September 2009. 1274 [RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using 1275 Relays around NAT (TURN): Relay Extensions to Session 1276 Traversal Utilities for NAT (STUN)", RFC 5766, April 2010. 1278 [SRVREG] "DNS SRV Service Types Registry", 1279 http://www.dns-sd.org/ServiceTypes.html. 1281 [SYSFORM] Internet Assigned Numbers Authority (IANA), "Application 1282 for System (Well Known) Port Number", 1283 http://www.iana.org/cgi-bin/sys-port-number.pl. 1285 [TRILOGY] "Trilogy Project", http://www.trilogy-project.org/. 1287 [USRFORM] Internet Assigned Numbers Authority (IANA), "Application 1288 for User (Registered) Port Number", 1289 http://www.iana.org/cgi-bin/usr-port-number.pl. 1291 Authors' Addresses 1293 Michelle Cotton 1294 Internet Corporation for Assigned Names and Numbers 1295 4676 Admiralty Way, Suite 330 1296 Marina del Rey, CA 90292 1297 USA 1299 Phone: +1 310 823 9358 1300 Email: michelle.cotton@icann.org 1301 URI: http://www.iana.org/ 1303 Lars Eggert 1304 Nokia Research Center 1305 P.O. Box 407 1306 Nokia Group 00045 1307 Finland 1309 Phone: +358 50 48 24461 1310 Email: lars.eggert@nokia.com 1311 URI: http://research.nokia.com/people/lars_eggert/ 1313 Joe Touch 1314 USC/ISI 1315 4676 Admiralty Way 1316 Marina del Rey, CA 90292 1317 USA 1319 Phone: +1 310 448 9151 1320 Email: touch@isi.edu 1321 URI: http://www.isi.edu/touch 1323 Magnus Westerlund 1324 Ericsson 1325 Torshamsgatan 23 1326 Stockholm 164 80 1327 Sweden 1329 Phone: +46 8 719 0000 1330 Email: magnus.westerlund@ericsson.com