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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 27, 2010 USC/ISI 8 M. Westerlund 9 Ericsson 10 S. Cheshire 11 Apple 12 May 26, 2010 14 Internet Assigned Numbers Authority (IANA) Procedures for the Management 15 of the Transport Protocol Port Number and Service Name Registry 16 draft-ietf-tsvwg-iana-ports-06 18 Abstract 20 This document defines the procedures that the Internet Assigned 21 Numbers Authority (IANA) uses when handling registration and other 22 requests related to the transport protocol port number and service 23 name registry. It also discusses the rationale and principles behind 24 these procedures and how they facilitate the long-term sustainability 25 of the registry. 27 This document updates IANA's procedures by obsoleting Sections 8 and 28 9.1 of the IANA allocation guidelines [RFC2780], it updates the IANA 29 allocation procedures for UDP-Lite [RFC3828], DCCP [RFC4340] and SCTP 30 [RFC4960], it updates the DNS SRV specification [RFC2782] to clarify 31 what a service name is and how it is registered. 33 Status of this Memo 35 This Internet-Draft is submitted in full conformance with the 36 provisions of BCP 78 and BCP 79. 38 Internet-Drafts are working documents of the Internet Engineering 39 Task Force (IETF). Note that other groups may also distribute 40 working documents as Internet-Drafts. The list of current Internet- 41 Drafts is at http://datatracker.ietf.org/drafts/current/. 43 Internet-Drafts are draft documents valid for a maximum of six months 44 and may be updated, replaced, or obsoleted by other documents at any 45 time. It is inappropriate to use Internet-Drafts as reference 46 material or to cite them other than as "work in progress." 48 This Internet-Draft will expire on November 27, 2010. 50 Copyright Notice 52 Copyright (c) 2010 IETF Trust and the persons identified as the 53 document authors. All rights reserved. 55 This document is subject to BCP 78 and the IETF Trust's Legal 56 Provisions Relating to IETF Documents 57 (http://trustee.ietf.org/license-info) in effect on the date of 58 publication of this document. Please review these documents 59 carefully, as they describe your rights and restrictions with respect 60 to this document. Code Components extracted from this document must 61 include Simplified BSD License text as described in Section 4.e of 62 the Trust Legal Provisions and are provided without warranty as 63 described in the Simplified BSD License. 65 This document may contain material from IETF Documents or IETF 66 Contributions published or made publicly available before November 67 10, 2008. The person(s) controlling the copyright in some of this 68 material may not have granted the IETF Trust the right to allow 69 modifications of such material outside the IETF Standards Process. 70 Without obtaining an adequate license from the person(s) controlling 71 the copyright in such materials, this document may not be modified 72 outside the IETF Standards Process, and derivative works of it may 73 not be created outside the IETF Standards Process, except to format 74 it for publication as an RFC or to translate it into languages other 75 than English. 77 Table of Contents 79 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 80 2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 81 3. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 6 82 4. Conventions Used in this Document . . . . . . . . . . . . . . 7 83 5. Service Names . . . . . . . . . . . . . . . . . . . . . . . . 8 84 5.1. Service Name Syntax . . . . . . . . . . . . . . . . . . . 9 85 5.2. Service Name Usage in DNS SRV Records . . . . . . . . . . 9 86 6. Port Number Ranges . . . . . . . . . . . . . . . . . . . . . . 10 87 6.1. Port Numbers and Service Names for Experimentation . . . . 11 88 7. Principles for Port Number and Service Name Registry 89 Management . . . . . . . . . . . . . . . . . . . . . . . . . . 11 90 7.1. Past Principles . . . . . . . . . . . . . . . . . . . . . 12 91 7.2. Updated Principles . . . . . . . . . . . . . . . . . . . . 12 92 7.3. Variances for Specific Port Number Ranges . . . . . . . . 15 93 8. IANA Procedures for Managing the Port Number and Service 94 Name Registry . . . . . . . . . . . . . . . . . . . . . . . . 16 95 8.1. Port Number and Service Name Registration . . . . . . . . 16 96 8.2. Port Number and Service Name De-Registration . . . . . . . 19 97 8.3. Port Number and Service Name Re-Use . . . . . . . . . . . 19 98 8.4. Port Number and Service Name Revocation . . . . . . . . . 20 99 8.5. Port Number and Service Name Transfers . . . . . . . . . . 21 100 8.6. Maintenance Issues . . . . . . . . . . . . . . . . . . . . 21 101 9. Security Considerations . . . . . . . . . . . . . . . . . . . 21 102 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 103 10.1. Service Name Consistency . . . . . . . . . . . . . . . . . 22 104 10.2. Port Numbers for SCTP and DCCP Experimentation . . . . . . 24 105 10.3. Updates to DCCP Registries . . . . . . . . . . . . . . . . 25 106 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 26 107 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26 108 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 109 13.1. Normative References . . . . . . . . . . . . . . . . . . . 27 110 13.2. Informative References . . . . . . . . . . . . . . . . . . 28 111 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29 113 1. Introduction 115 For many years, the allocation and registration of new port number 116 values and service names for use with the Transmission Control 117 Protocol (TCP) [RFC0793] and the User Datagram Protocol (UDP) 118 [RFC0768] have had less than clear guidelines. New transport 119 protocols have been added - the Stream Control Transmission Protocol 120 (SCTP) [RFC4960] and the Datagram Congestion Control Protocol (DCCP) 121 [RFC4342] - and new mechanisms like DNS SRV records [RFC2782] have 122 been developed, each with separate registries and separate 123 guidelines. The community recognized the need for additional 124 procedures beyond just assignment; notably modification, revocation, 125 and release. 127 A key factor of this procedural streamlining is to establish 128 identical registration procedures for all IETF transport protocols. 129 This document brings the IANA procedures for TCP and UDP in line with 130 those for SCTP and DCCP, resulting in a single process that 131 requesters and IANA follow for all requests for all transport 132 protocols, including those not yet defined. 134 In addition to detailing the IANA procedures for the initial 135 assignment of port numbers and service names, this document also 136 specifies post-assignment procedures that until now have been handled 137 in an ad hoc manner. These include procedures to de-register a port 138 number that is no longer in use, to re-use a port number allocated 139 for one application that is no longer in use for another application, 140 and the procedure by which IANA can unilaterally revoke a prior port 141 number registration. Section 8 discusses the specifics of these 142 procedures and processes that requesters and IANA follow for all 143 requests for all current and future transport protocols. 145 It is important to note that ownership of registered port numbers and 146 service names remains with IANA. For protocols developed by IETF 147 working groups, IANA now also offers a method for the "early" 148 assignment of port numbers and service names [RFC4020], as described 149 in Section 8.1. 151 This document updates IANA's procedures for UDP and TCP port numbers 152 by obsoleting Sections 8 and 9.1 of the IANA allocation guidelines 153 [RFC2780]. (Note that different sections of the IANA allocation 154 guidelines, relating to the protocol field values in IPv4 header, 155 were also updated in February 2008 [RFC5237].) This document also 156 updates the IANA allocation procedures for DCCP [RFC4340] and SCTP 157 [RFC4960]. 159 The Lightweight User Datagram Protocol (UDP-Lite) [RFC5237] shares 160 the port space with UDP. The UDP-Lite specification says: "UDP-Lite 161 uses the same set of port number values assigned by the IANA for use 162 by UDP". Thus the update of UDP procedures result in an update also 163 of the UDP-Lite procedures. 165 This document also clarify what a service name is and how it is 166 registered. This will impact the DNS SRV specification, because that 167 specification merely makes a brief mention that the symbolic names of 168 services are defined in "Assigned Numbers" [RFC1700], without stating 169 to which section of that 230-page document it refers. The DNS SRV 170 specification may have been referring to the list of Port Assignments 171 (known as /etc/services on Unix), or to the "Protocol And Service 172 Names" section, or to both, or to some other section. Furthermore, 173 "Assigned Numbers" is now obsolete [RFC3232] and has now been 174 replaced by on-line registries [PORTREG][PROTSERVREG]. There are 175 additional updates and clarifications on how DNS SRV utilize the 176 Service name registry created in this document in "Clarification of 177 DNS SRV Owner Names" [I-D.gudmundsson-dnsext-srv-clarify]. 179 The development of new transport protocols is a major effort that the 180 IETF does not undertake very often. If a new transport protocol is 181 standardized in the future, for the purpose of uniformity it is 182 expected to follow as much as possible the guidelines and practices 183 around using port numbers and service names. 185 2. Motivation 187 Information about the registration procedures for the port registry 188 has existed in three locations: the forms for requesting port number 189 registrations on the IANA web site [SYSFORM] [USRFORM], an 190 introductory text section in the file listing the port number 191 registrations themselves [PORTREG], and two brief sections of the 192 IANA Allocation Guidelines [RFC2780]. 194 Similarly, the procedures surrounding service names have been 195 historically unclear. Service names were originally created as 196 mnemonic identifiers for port numbers without a well-defined syntax, 197 beyond the 14-character limit mentioned on the IANA website [SYSFORM] 198 [USRFORM]. Even that length limit has not been consistently applied, 199 and some assigned service names are 15 characters long. When service 200 identification via DNS SRV RRs was introduced, the requirement by 201 IANA to only assign service names and port numbers in combination, 202 led to the creation of an ad hoc service name registry outside of the 203 control of IANA [SRVREG]. 205 This document aggregates all this scattered information into a single 206 reference that aligns and clearly defines the management procedures 207 for both port numbers and service names. It gives more detailed 208 guidance to prospective requesters of ports and service names than 209 the existing documentation, and it streamlines the IANA procedures 210 for the management of the registry, so that management requests can 211 complete in a timely manner. 213 This document defines rules for registration of service names without 214 associated port numbers, for such usages as DNS SRV records 215 [RFC2782], which was not possible under the previous IANA procedures. 216 The document also merges service name registrations from the non-IANA 217 ad hoc registry [SRVREG] and from the IANA "Protocol and Service 218 Names" registry [PROTSERVREG] into the IANA "Port and Service Name" 219 registry [PORTREG], which from here on is the single authoritative 220 registry for service names and port numbers. 222 An additional purpose of this document is to describe the principles 223 that guide the IETF and IANA in their role as the long-term joint 224 stewards of the port number registry. TCP and UDP have been a 225 remarkable success over the last decades. Thousands of applications 226 and application-level protocols have registered ports and service 227 names for their use, and there is every reason to believe that this 228 trend will continue into the future. It is hence extremely important 229 that management of the registry follow principles that ensure its 230 long-term usefulness as a shared resource. Section 7 discusses these 231 principles in detail. 233 3. Background 235 The Transmission Control Protocol (TCP) [RFC0793] and the User 236 Datagram Protocol (UDP) [RFC0768] have enjoyed a remarkable success 237 over the decades as the two most widely used transport protocols on 238 the Internet. They have relied on the concept of "ports" as logical 239 entities for Internet communication. Ports serve two purposes: 240 first, they provide a demultiplexing identifier to differentiate 241 transport sessions between the same pair of endpoints, and second, 242 they may also identify the application protocol and associated 243 service to which processes bind. Newer transport protocols, such as 244 the Stream Control Transmission Protocol (SCTP) [RFC4960] and the 245 Datagram Congestion Control Protocol (DCCP) [RFC4342] have adopted 246 the concept of ports for their communication sessions and use 16-bit 247 port numbers in the same way as TCP and UDP (and UDP-Lite [RFC3828], 248 a variant of UDP). 250 Port numbers are the original and most widely used means for 251 application and service identification on the Internet. Ports are 252 16-bit numbers, and the combination of source and destination port 253 numbers together with the IP addresses of the communicating end 254 systems uniquely identifies a session of a given transport protocol. 256 Port numbers are also known by their corresponding service names such 257 as "telnet" for port number 23 and "http" (and the "www" alias) for 258 port number 80. 260 Hosts running services, hosts accessing services on other hosts, and 261 intermediate devices (such as firewalls and NATs) that restrict 262 services need to agree on which service corresponds to a particular 263 destination port. Although this is ultimately a local decision with 264 meaning only between the endpoints of a connection, it is common for 265 many services to have a default port upon which those servers usually 266 listen, when possible, and these ports are recorded by the Internet 267 Assigned Numbers Authority (IANA) through the port number registry 268 [PORTREG]. 270 Over time, the assumption that a particular port number necessarily 271 implies a particular service may become less true. For example, 272 multiple instances of the same service on the same host cannot 273 generally listen on the same port, and multiple hosts behind the same 274 NAT gateway cannot all have a mapping for the same port on the 275 external side of the NAT gateway, whether using static port mappings 276 configured by hand by the user, or dynamic port mappings configured 277 automatically using a port mapping protocol NAT Port Mapping Protocol 278 (NAT-PMP) [I-D.cheshire-nat-pmp] or Internet Gateway Device (IGD) 279 [IGD]. 281 Applications either use numeric port numbers directly, look up port 282 numbers based on service names via system calls such as 283 getservbyname() on UNIX, look up port numbers by performing queries 284 for DNS SRV records [RFC2782][I-D.cheshire-dnsext-dns-sd] or 285 determine port numbers in a variety of other ways like the TCP Port 286 Service Multiplexer (TCPMUX) [RFC1078]. 288 Designers of applications and application-level protocols may apply 289 to IANA for an assigned port number and service name for a specific 290 application, and may - after successful registration - assume that no 291 other application will use that port number or service name for its 292 communication sessions. Alternatively, application designers may 293 also ask for only an assigned service name, if their application does 294 not require a fixed port number. The latter alternative is 295 encouraged when possible, in order to conserve the more limited port 296 number space. This includes, for example, applications that use DNS 297 SRV records to look up port numbers at runtime. 299 4. Conventions Used in this Document 301 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 302 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 303 document are to be interpreted as described in [RFC2119]. 305 5. Service Names 307 Service names are the unique key in the Port and Service Name 308 registry. This unique symbolic name for a service may also be used 309 for other purposes, such as in DNS SRV records [RFC2782]. Within the 310 registry, this unique key ensures that different services can be 311 unambiguously distinguished, thus preventing name collisions and 312 avoiding confusion about who is the administrative contact for a 313 particular entry. 315 For each service name, there may exist zero or more associated port 316 number assignments. A port number assignment associated with a 317 service name contains the transport protocol, port number and 318 possibly additional data, such as a DCCP Service Code. 320 There may be more than one service name associated with a particular 321 transport protocol and port. There are two valid reasons for 322 allowing service name aliases: 324 o Aliases are permissible when all such service names are for the 325 same service, such as with "http" and "www", which both name TCP 326 port 80. In such cases, one of the service names SHOULD be 327 designated primary, for use with mechanisms such as DNS SRV 328 Records [RFC2782], and the others SHOULD be designated as aliases 329 of the primary service name. This is necessary so that clients 330 and servers using a service discovery mechanism use a consistent 331 name by which to refer to a given service. Otherwise, if a server 332 were to advertise that it supports the "www" service, and a client 333 were to seek instances of the "http" service, that client would 334 fail to discover that server, defeating the purpose of having a 335 service discovery mechanism. For aliases that do not indicate a 336 primary alias, a server is expected to register itself under all 337 aliased service names. 339 o Aliases are also permissible when one service is an extension of 340 another service, and an in-band mechanisms exists for determining 341 if the extension is present or not. One example is port 3478, 342 which has the service name aliases "stun" and "turn". TURN 343 [RFC5766] is an extension to the STUN [RFC5389] service. TURN- 344 enabled clients wishing to locate TURN servers could attempt to 345 discover "stun" services and then checking in-band if the server 346 supports TURN, but this is inefficient. Enabling them to directly 347 query for "turn" servers by name is a better approach. (Note that 348 TURN servers in this case should also be locatable via a "stun" 349 discovery, because every TURN server is also a STUN server.) 351 Service names are assigned on a "first come, first served" basis, as 352 described in Section 8.1. Names should be brief and informative, 353 avoiding words or abbreviations that are redundant in the context of 354 the registry (e.g., "port", "service", "protocol", etc.) Names 355 referring to discovery services, e.g., using multicast or broadcast 356 to identify endpoints capable of a given service, SHOULD use an 357 easily identifiable suffix (e.g., "-disc"). 359 5.1. Service Name Syntax 361 Valid service names MUST contain only these US-ASCII [ANSI.X3-4.1986] 362 characters: letters from A to Z and a to z, digits from 0 to 9, and 363 hyphens ("-", ASCII 0x2D or decimal 45). They MUST be at least one 364 character and no more than fifteen characters long, MUST NOT begin or 365 end with a hyphen, and MUST NOT consist of only digits (in order to 366 be distinguishable from port numbers, which are typically written as 367 all digits). 369 The service name syntax MAY be used to validate a service name 370 string, but MUST NOT be used for any other purpose (e.g., 371 delineation). Any system that includes a service name inside a 372 longer string is itself responsible for delineating the service name. 373 Such systems MUST NOT rely on the syntax of a service name alone for 374 such delineation. 376 The syntax defined in ABNF [RFC5234]: 378 SRVNAME = (ALPHA / *([HYPHEN] ALNUM)) / 379 (1*DIGIT ((HYPHEN ALNUM) / ALPHA) *([HYPHEN] ALNUM)) 380 ALNUM = ALPHA / DIGIT ; A-Z, a-z, 0-9 381 HYPHEN = %x2d ; "-" 382 ALPHA = 383 DIGIT = 385 5.2. Service Name Usage in DNS SRV Records 387 The DNS SRV specification [RFC2782] requests that the Service Label 388 part of the owner name of DNS SRV records includes a "Service" 389 element, defined to be "the symbolic name of the desired service", 390 but did not state precisely which part of the IANA database (i.e. 391 STD 2 when [RFC2782] was written) serves as a registry for standard 392 service names. 394 This document clarifies that the Service Label MUST be a service name 395 as defined herein. The service name SHOULD be registered with IANA 396 and recorded in the Service Names and Port Numbers registry 397 [PORTREG]. This is needed to ensure that only a single registry of 398 Service Names exists and name collisions can be avoided in the 399 future. 401 The details of the use of Service Names from [PORTREG] in SRV Service 402 Labels are specified in [RFC2782] and the documents updating or 403 replacing that specification (see the companion document 404 [I-D.gudmundsson-dnsext-srv-clarify] for more information). 406 The details of how applications make use of DNS SRV should be 407 specified in the documentation set of the application/service. In 408 the absence of such specification, prospective clients of a given 409 service should not assume the existence of SRV RRs for this service 410 or, if they have indications that this will be the case (e.g., by 411 configuration), must assume the unextended naming scheme from 412 [RFC2782] for service discovery with DNS SRV, i.e., the Service Label 413 is constructed from the Service Name registered in [PORTREG] by 414 prepending a single underscore character ("_"). 416 6. Port Number Ranges 418 TCP, UDP, UDP-Lite, SCTP and DCCP use 16-bit namespaces for their 419 port number registries. The port registries for all these transport 420 protocols are subdivided into three ranges of numbers, and 421 Section 7.3 describes the IANA procedures for each range in detail: 423 o the Well Known Ports, also known as the System Ports, from 0-1023 424 (assigned by IANA) 426 o the Registered Ports, also known as the User Ports, from 1024- 427 49151 (assigned by IANA) 429 o the Dynamic Ports, also known as the Private Ports, from 49152- 430 65535 (never assigned) 432 Of the assignable port ranges (Well Known and Registered, i.e., port 433 numbers 0-49151), individual port numbers are in one of three states 434 at any given time: 436 o Assigned: Assigned port numbers are currently allocated to the 437 service indicated in the registry. 439 o Unassigned: Unassigned port numbers are currently available for 440 assignment upon request, as per the procedures outlined in this 441 document. 443 o Reserved: Reserved port numbers are not available for regular 444 assignment; they are "assigned to IANA" for special purposes. 446 Reserved port numbers include values at the edges of each range, 447 e.g., 0, 1023, 1024, etc., which may be used to extend these 448 ranges or the overall port number space in the future. 450 In order to keep the size of the registry manageable, IANA typically 451 only records the Assigned and Reserved port numbers and service names 452 in the registry. Unassigned values are typically not explicitly 453 listed. 455 As a data point, when this document was written, approximately 76% of 456 the TCP and UDP Well Known Ports were assigned, and approximately 9% 457 of the Registered Ports were assigned. (As noted, Dynamic Ports are 458 never assigned.) 460 6.1. Port Numbers and Service Names for Experimentation 462 Of the Well Known ports, two TCP and UDP port numbers (1021 and 463 1022), together with their respective service names ("exp1" and 464 "exp2"), have been assigned for experimentation with new applications 465 and application-layer protocols that require a port number in the 466 assigned ports ranges [RFC4727]. 468 Please refer to Sections 1 and 1.1 of "Assigning Experimental and 469 Testing Numbers Considered Useful" [RFC3692] for how these 470 experimental port numbers are to be used. 472 This document registers the same two port numbers and service names 473 for experimentation with new application-layer protocols over SCTP 474 and DCCP in Section 10.2. 476 Unfortunately, it can be difficult to limit access to these ports. 477 Users SHOULD take measures to ensure that experimental ports are 478 connecting to the intended process. For example, users of these 479 experimental ports might include a 64-bit nonce, once on each segment 480 of a message-oriented channel (e.g., UDP), or once at the beginning 481 of a byte-stream (e.g., TCP), which is used to confirm that the port 482 is being used as intended. Such confirmation of intended use is 483 especially important when these ports are associated with privileged 484 (e.g., system or administrator) processes. 486 7. Principles for Port Number and Service Name Registry Management 488 Management procedures for the port number and service name registry 489 include allocation of port numbers and service names upon request, as 490 well as coordination of information about existing allocations. The 491 latter includes maintaining contact and description information about 492 assignments, revoking abandoned assignments, and redefining 493 assignments when needed. Of these procedures, port number allocation 494 is most critical, in order to continue to conserve the remaining port 495 numbers. 497 As noted earlier, only ~9% of the Registered Port space is currently 498 assigned. The current rate of assignment is approximately 400 ports/ 499 year, and has remained linear for the past 8 years. At that rate, if 500 similar conservation continues, this resource will sustain another 85 501 years of assignment - without the need to resort to reassignment of 502 released values or revocation. Note that the namespace available for 503 service names is even larger, which allows for a simpler management 504 procedures. 506 7.1. Past Principles 508 Before the publication of this document, the principles of port 509 number and service name management followed a few mostly-undocumented 510 guidelines. They are recorded here for historical purposes, and this 511 document updates them in Section 7.2. These principles were: 513 o TCP and UDP ports were simultaneously allocated when either was 514 requested 516 o Port numbers were the primary allocation; service names were 517 informative only, and did not have a well-defined syntax 519 o Port numbers were conserved informally, and sometimes 520 inconsistently (e.g., some services were allocated ranges of many 521 port numbers even where not strictly necessary) 523 o SCTP and DCCP port number and service name registries were managed 524 separately from the TCP/UDP registries 526 o Service names could not be assigned in the ports registry without 527 assigning a corresponding port number at the same time 529 This document clarifies and aligns these guidelines in order to more 530 conservatively manage the limited remaining port number space and to 531 enable and promote the use of service names for service 532 identification without associated port numbers, where possible. 534 7.2. Updated Principles 536 This section summarizes the basic principles by which IANA handles 537 the Port and Service Name registry, and attempts to conserve the port 538 number space. This description is intended to inform applicants 539 requesting service names and port numbers. IANA decisions are not 540 required to be bound to these principles, however; other factors may 541 come into play, and exceptions may occur where deemed in the best 542 interest of the Internet. 544 IANA will begin assigning service names that do not request a 545 corresponding port number allocation under a simple "First Come, 546 First Served" policy [RFC5226]. IANA MAY, at its discretion, refer 547 service name requests to "Expert Review" in cases of mass 548 registrations or other situations where IANA believes expert review 549 is advisable. 551 The basic principle of port number registry management is to conserve 552 use of the port space where possible. Extensions to support larger 553 port number spaces would require changing many core protocols of the 554 current Internet in a way that would not be backward compatible and 555 interfere with both current and legacy applications. To help ensure 556 this conservation the policy for any registration request for port 557 number allocations uses the "Expert Review" policy [RFC5226]. 559 Conservation of the port number space is required because this space 560 is a limited resource, applications are expected to participate in 561 the traffic demultiplexing process where feasible. The port numbers 562 are expected to encode as little information as possible that will 563 still enable an application to perform further demultiplexing by 564 itself. In particular: 566 o IANA will allocate only one assigned port number per service or 567 application 569 o IANA will allocate only one assigned port number for all versions 570 of a service (e.g., running the service with or without a security 571 mechanism, or for updated variants of a service) 573 o IANA will allocate only one assigned port number for all different 574 types of device using or participating in the same service 576 o IANA will allocate port numbers only for the transport protocol(s) 577 explicitly named in an registration request 579 o IANA may recover unused port numbers, via the new procedures of 580 de-registration, revocation, and transfer 582 A given service is expected to further demultiplex messages where 583 possible. For example, applications and protocols are expected to 584 include in-band version information, so that future versions of the 585 application or protocol can share the same allocated port. 586 Applications and protocols are also expected to be able to 587 efficiently use a single allocated port for multiple sessions, either 588 by demultiplexing multiple streams within one port, or using the 589 allocated port to coordinate using dynamic ports for subsequent 590 exchanges (e.g., in the spirit of FTP [RFC0959]). 592 Ports are used in various ways, notably: 594 o as endpoint process identifiers 596 o as application protocol identifiers 598 o for firewall filtering purposes 600 The process and protocol identifier use suggests that anything a 601 single process can demultiplex, or that can be encoded into a single 602 protocol, should be. The firewall filtering use suggests that some 603 uses that could be multiplexed or encoded must be separated to allow 604 for firewall management. Note that this latter use is much less 605 sound, because port numbers have meaning only for the two endpoints 606 involved in a connection, and drawing conclusions about the service 607 that generated a given flow based on observed port numbers is not 608 always reliable. Further, previous separation of protocol variants 609 based on security capabilities (e.g., HTTP on TCP port 80 vs. HTTPS 610 on TCP port 443) is not recommended for new protocols, because all 611 should be security-capable and capable of negotiating the use of 612 security in-band. 614 IANA will begin assigning port numbers for only those transport 615 protocols explicitly included in a registration request. This ends 616 the long-standing practice of automatically assigning a port number 617 to an application for both TCP and a UDP, even if the request is for 618 only one of these transport protocols. The new allocation procedure 619 conserves resources by allocating a port number to an application for 620 only those transport protocols (TCP, UDP, SCTP and/or DCCP) it 621 actually uses. The port number will be marked as Reserved - instead 622 of Assigned - in the port number registries of the other transport 623 protocols. When applications start supporting the use of some of 624 those additional transport protocols, the administrative contact for 625 the registration MUST request IANA to convert the reservation into a 626 proper assignment. An application MUST NOT assume that it can use a 627 port number assigned to it for use with one transport protocol with 628 another transport protocol without asking IANA to convert the 629 reservation into an assignment. 631 When the available pool of unassigned numbers has run out in a ports 632 range, it will be necessary for IANA to consider the Reserved ports 633 for assignment. This is part of the motivation to not automatically 634 assigning ports for other transport protocols than the requested 635 ones. This will allow more ports to be available for assignment at 636 that point. It also shows the importance to register the transport 637 protocols that are in fact used. 639 Conservation of port numbers is improved by procedures that allow 640 previously allocated port numbers to become Unassigned, either 641 through de-registration or through revocation, and by a procedure 642 that lets application designers transfer an allocated but unused port 643 number to a new application. Section 8 describes these procedures, 644 which so far were undocumented. Port number conservation is also 645 improved by recommending that applications that do not require an 646 allocated port chose this option and register only a service name. 648 7.3. Variances for Specific Port Number Ranges 650 Section 6 describes the different port number ranges. It is 651 important to note that IANA applies slightly different procedures 652 when managing the different ranges of the port number registry: 654 o Ports in the Dynamic Ports range (49152-65535) have been 655 specifically set aside for local and dynamic use and cannot be 656 registered through IANA. Applications may simply use them for 657 communication without any sort of registration. On the other 658 hand, applications MUST NOT assume that a specific port number in 659 the Dynamic Ports range will always be available for communication 660 at all times, and a port number in that range hence MUST NOT be 661 used as a service identifier. 663 o Ports in the Registered Ports range (1024-49151) are available for 664 registration through IANA, and MAY be used as service identifiers 665 upon successful registration. Because registering a port number 666 for a specific application consumes a fraction of the shared 667 resource that is the port number registry, IANA will require the 668 requester to document the intended use of the port number. This 669 documentation will be input to the "Expert Review" allocation 670 procedure [RFC5226], by which IANA will have a technical expert 671 review the request to determine whether to grant the registration. 672 The submitted documentation MUST explain why using a port number 673 in the Dynamic Ports range is unsuitable for the given 674 application. Ports in the Registered Ports range may also be 675 assigned under the "IETF Review" or "IESG Approval" allocation 676 procedures [RFC5226], which is how most assignments for IETF 677 protocols are handled. 679 o Ports in the Well Known Ports range (0-1023) are also available 680 for registration through IANA. Because the Well Known Ports range 681 is both the smallest and the most densely allocated, the 682 requirements for new allocations are more strict than those for 683 the Registered Ports range, and will only be granted under the 684 "IETF Review" or "IESG Approval" allocation procedures [RFC5226]. 686 A request for a Well Known port number MUST document why using a 687 port number from both the Registered Ports and Dynamic Ports 688 ranges is unsuitable for the given application. 690 8. IANA Procedures for Managing the Port Number and Service Name 691 Registry 693 This section describes the process for requests associated with 694 IANA's management of the port number and service name registry. Such 695 requests include initial registration, de-registration, re-use, 696 changes to the service name, as well as updates to the contact 697 information or description associated with an assignment. Revocation 698 is initiated by IANA. 700 8.1. Port Number and Service Name Registration 702 Registration refers to the allocation of port numbers or service 703 names to applicants. All such registrations are made from port 704 numbers or service names that are Unassigned or Reserved at the time 705 of the allocation. Unassigned numbers and names are allocated as 706 needed, and without further explanation. Reserved numbers and names 707 are assigned only after review by IANA and the IETF, and are 708 accompanied by a statement explaining the reason a Reserved number or 709 name is appropriate for this action. 711 When a registration for one or more transport protocols is approved, 712 the port number for any non-requested transport protocol(s) will be 713 marked as Reserved. IANA SHOULD NOT assign that port number to any 714 other application or service until no other port numbers remain 715 Unassigned in the requested range. The current administrative 716 contact for a port number MAY register these Reserved port numbers 717 for other transport protocols when needed. 719 Service names, on the other hand, are not tied to a specific 720 transport protocol, and registration requests for only a service name 721 (but not a port number) allocate that service name for use with all 722 transport protocols. 724 A port number or service name registration request contains some or 725 all of the following information. The combination of service name 726 and transport protocol is the unique identifier of a given service: 728 Service Name (REQUIRED) 729 Transport Protocol(s) (REQUIRED) 730 Registration Administrative Contact (REQUIRED) 731 Registration Technical Contact (REQUIRED) 732 Port Number (OPTIONAL) 733 Service Code (only REQUIRED for DCCP) 734 Description (REQUIRED) 735 Reference (REQUIRED) 736 Known Unauthorized Uses (OPTIONAL) 737 Assignment Notes (OPTIONAL) 739 o Service Name: A desired unique service name for the service 740 associated with the registration request MUST be provided, for use 741 in various service selection and discovery mechanisms (including, 742 but not limited to, DNS SRV records [RFC2782]). The name MUST be 743 compliant with the syntax defined in Section 5.1. In order to be 744 unique, they MUST NOT be identical to any currently registered 745 service names in the IANA registry [PORTREG]. Service names are 746 case-insensitive; they may be provided and entered into the 747 registry with mixed case (e.g., for clarity), but for the purposes 748 of comparison, the case is ignored. 750 o Transport Protocol(s): The transport protocol(s) for which the 751 allocation is requested MUST be provided. This field is currently 752 limited to one or more of TCP, UDP, SCTP, and DCCP. This field is 753 required even for services with no port number. 755 o Registration Administrative Contact: Name and email address of the 756 administrative contact for the registration. This is REQUIRED. 757 The name of the administrative contact identifies the 758 organization, company, or individual who is responsible for the 759 registration. For registrations done through IETF-published RFCs, 760 the administrative contact will be the IESG. 762 o Registration Technical Contact: Name and email address of the 763 technical contact person for the registration. This is REQUIRED. 764 For individuals, this is the same as the Registration 765 Administrative Contact; for organizations, this is a point of 766 contact at that organization. Additional address information MAY 767 be provided. For registrations done through IETF-published RFCs, 768 the technical contact will be the IESG. 770 o Port Number: If assignment of a port number is desired, either the 771 currently Unassigned port number the requester suggests for 772 allocation, or the text "ANY", MUST be provided. If only a 773 service name is to be assigned, this field MUST be empty. If a 774 specific port number is requested, IANA is encouraged to allocate 775 the requested number. If the text "ANY" is specified, IANA will 776 choose a suitable number from the Registered Ports range. Note 777 that the applicant MUST NOT use the requested port prior to the 778 completion of the registration. 780 o Service Code: The request MUST include a desired unique DCCP 781 service code [RFC5595], if the registration request includes DCCP 782 as a transport protocol, and MUST NOT include a requested DCCP 783 service code otherwise. Section 19.8 of [RFC4340] defines 784 requirements and rules for allocation, updated by this document. 786 o Description: A short description of the service associated with 787 the registration request is REQUIRED. It should avoid all but the 788 most well known acronyms. 790 o Reference: A description of (or a reference to a document 791 describing) the protocol or application using this port. The 792 description must include whether the protocol uses either 793 broadcast, multicast, or anycast communication. 795 For registrations requesting only a Service Name or a Service Name 796 and Registered Port, a statement that the protocol is proprietary 797 and not publicly documented is also acceptable provided that the 798 above information regarding use of broadcast, multicast, or 799 anycast is given. 801 For registration requests for a Registered Port, the registration 802 request MUST explain why a port number in the Dynamic Ports range 803 is unsuitable for the given application. 805 For registration requests for a Well Known Port, the registration 806 request MUST explain why a port number in the Registered Ports or 807 Dynamic Ports ranges is unsuitable, and a reference to a stable 808 protocol specification document MUST be provided. For requests 809 from IETF Working Groups, IANA MAY accept "Early" registration 810 requests referencing a sufficiently stable Internet Draft instead 811 of a published Standards-Track RFC [RFC4020]. 813 o Known Unauthorized Uses: A list of uses by applications or 814 organizations who are not the assignee. This list may be 815 augmented by IANA after assignment when unauthorized uses are 816 reported. 818 o Assignment Notes: Indications of owner/name change, or any other 819 assignment process issue. This list may be updated by IANA after 820 assignment to help track changes to an assignment, e.g., de- 821 registration, owner/name changes, etc. 823 If the registration request is for the addition of a new transport 824 protocol to an already assigned service name, IANA needs to confirm 825 with the administrative contact for the existing assignment whether 826 this addition is appropriate. 828 If the registration request is for a service name alias (see 829 Section 5), IANA needs to confirm with the administrative contact for 830 the existing service name whether the registration of the alias is 831 appropriate. 833 When IANA receives a registration request - containing the above 834 information - that is requesting a port number, IANA SHALL initiate 835 an "Expert Review" [RFC5226] in order to determine whether an 836 assignment should be made. For requests that do not include a port 837 number, IANA SHOULD assign the service name under a simple "First 838 Come First Served" policy [RFC5226]. 840 8.2. Port Number and Service Name De-Registration 842 The administrative contact of a granted port number assignment can 843 return the port number to IANA at any time if they no longer have a 844 need for it. The port number will be de-registered and will be 845 marked as Reserved. IANA should not re-assign port numbers that have 846 been de-registered until all other available port numbers in the 847 specific range have been assigned. 849 Before proceeding with a port number de-registration, IANA needs to 850 reasonably establish that the value is actually no longer in use. 852 Because there is much less danger of exhausting the service name 853 space compared to the port number space, it is RECOMMENDED that a 854 given service name remain assigned even after all associated port 855 number assignments have become de-registered. Under this policy, it 856 will appear in the registry as if it had been created through a 857 service name registration request that did not include any port 858 numbers. 860 On rare occasions, it may still be useful to de-register a service 861 name. In such cases, IANA will mark the service name as Reserved. 862 IANA will involve their IESG-appointed expert in such cases. 864 8.3. Port Number and Service Name Re-Use 866 If the administrative contact of a granted port number assignment no 867 longer have a need for the registered number, but would like to re- 868 use it for a different application, they can submit a request to IANA 869 to do so. 871 Logically, port number re-use is to be thought of as a de- 872 registration (Section 8.2) followed by an immediate re-registration 873 (Section 8.1) of the same port number for a new application. 874 Consequently, the information that needs to be provided about the 875 proposed new use of the port number is identical to what would need 876 to be provided for a new port number allocation for the specific 877 ports range. 879 Because there is much less danger of exhausting the service name 880 space compared to the port number space, it is RECOMMENDED that the 881 original service name associated with the prior use of the port 882 number remains assigned, and a new service be created and associated 883 with the port number. This is again consistent with viewing a re-use 884 request as a de-registration followed by an immediate re- 885 registration. Re-using an assigned service name for a different 886 application is NOT RECOMMENDED. 888 IANA needs to carefully review such requests before approving them. 889 In some instances, the Expert Reviewer will determine that the 890 application that the port number was assigned to has found usage 891 beyond the original requester, or that there is a concern that it may 892 have such users. This determination MUST be made quickly. A 893 community call concerning revocation of a port number (see below) MAY 894 be considered, if a broader use of the port number is suspected. 896 8.4. Port Number and Service Name Revocation 898 A port number revocation can be thought of as an IANA-initiated de- 899 registration (Section 8.2), and has exactly the same effect on the 900 registry. 902 Sometimes, it will be clear that a specific port number is no longer 903 in use and that IANA can revoke it and mark it as Reserved. At other 904 times, it may be unclear whether a given assigned port number is 905 still in use somewhere in the Internet. In those cases, IANA must 906 carefully consider the consequences of revoking the port number, and 907 SHOULD only do so if there is an overwhelming need. 909 With the help of their IESG-appointed Expert Reviewer, IANA SHALL 910 formulate a request to the IESG to issue a four-week community call 911 concerning the pending port number revocation. The IESG and IANA, 912 with the Expert Reviewer's support, SHALL determine promptly after 913 the end of the community call whether revocation should proceed and 914 then communicate their decision to the community. This procedure 915 typically involves similar steps to de-registration except that it is 916 initiated by IANA. 918 Because there is much less danger of exhausting the service name 919 space compared to the port number space, revoking service names is 920 NOT RECOMMENDED. 922 8.5. Port Number and Service Name Transfers 924 The value of port numbers and service names is defined by their 925 careful management as a shared Internet resource, whereas enabling 926 transfer allows the potential for associated monetary exchanges. As 927 a result, the IETF does not permit port number or service name 928 assignments to be transferred between parties, even when they are 929 mutually consenting. 931 The appropriate alternate procedure is a coordinated de-registration 932 and registration: The new party requests the port number or service 933 name via a registration and the previous party releases its 934 assignment via the de-registration procedure outlined above. 936 With the help of their IESG-appointed Expert Reviewer, IANA SHALL 937 carefully determine if there is a valid technical, operational or 938 managerial reason to grant the requested new assignment. 940 8.6. Maintenance Issues 942 In addition to the formal procedures described above, updates to the 943 Description and Technical Contact information are coordinated by IANA 944 in an informal manner, and may be initiated by either the registrant 945 or by IANA, e.g., by the latter requesting an update to current 946 contact information. (Note that Registration Administrative Contact 947 cannot be changed; see Section 8.5 above.) 949 9. Security Considerations 951 The IANA guidelines described in this document do not change the 952 security properties of UDP, TCP, SCTP, or DCCP. 954 Assignment of a port number or service name does not in any way imply 955 an endorsement of an application or product, and the fact that 956 network traffic is flowing to or from a registered port number does 957 not mean that it is "good" traffic, or even that it is used by the 958 assigned service. Firewall and system administrators should choose 959 how to configure their systems based on their knowledge of the 960 traffic in question, not whether there is a port number or service 961 name registered or not. 963 Services are expected to include support for security, either as 964 default or dynamically negotiated in-band. The use of separate port 965 number or service name assignments for secure and insecure variants 966 of the same service is to be avoided in order to discourage the 967 deployment of insecure services. 969 10. IANA Considerations 971 This document obsoletes Sections 8 and 9.1 of the March 2000 IANA 972 Allocation Guidelines [RFC2780]. 974 Upon approval of this document, IANA is requested to contact the 975 maintainer of the [SRVREG] registry, in order to merge the contents 976 of that private registry into the official IANA registry. It is 977 expected that the contents of [SRVREG] will at that time be replaced 978 with pointers to the IANA registry and to this RFC. 980 IANA is instructed to create a new service name entry in the port 981 number registry [PORTREG] for any entry in the "Protocol and Service 982 Names" registry [PROTSERVREG] that does not already have one 983 assigned. 985 IANA is also instructed to indicate which service name aliases in the 986 existing registry are the primary aliases (see Section 5). 988 10.1. Service Name Consistency 990 Section 8.1 defines which character strings are well-formed service 991 names, which until now had not been clearly defined. The definition 992 in Section 8.1 was chosen to allow maximum compatibility of service 993 names with current and future service discovery mechanisms. 995 As of August 5, 2009 approximately 98% of the so-called "Short Names" 996 from existing port number registrations [PORTREG] meet the rules for 997 legal service names stated in Section 8.1, and hence will be used 998 unmodified. 1000 The remaining approximately 2% of the exiting "Short Names" are not 1001 suitable to be used directly as well-formed service names because 1002 they contain illegal characters such as asterisks, dots, pluses, 1003 slashes, or underscores. All existing "Short Names" conform to the 1004 length requirement of 15 characters or fewer. For these unsuitable 1005 "Short Names", listed in the table below, the service name will be 1006 the Short Name with any illegal characters replaced by hyphens. IANA 1007 SHALL add an entry to the registry giving the new well-formed primary 1008 service name for the existing service, that otherwise duplicates the 1009 original assignment information. In the description field of this 1010 new entry giving the primary service name, IANA SHALL record that it 1011 assigns a well-formed service name for the previous service and 1012 reference the original assignment. In the description field of the 1013 original assignment, IANA SHALL add a note that this entry is an 1014 alias to the new well-formed service name, and that the old service 1015 name is historic, not usable for use with many common service 1016 discovery mechanisms. 1018 Names containing illegal characters to be replaced by hyphens: 1020 +----------------+-----------------+-----------------+ 1021 | 914c/g | acmaint_dbd | acmaint_transd | 1022 | atex_elmd | avanti_cdp | badm_priv | 1023 | badm_pub | bdir_priv | bdir_pub | 1024 | bmc_ctd_ldap | bmc_patroldb | boks_clntd | 1025 | boks_servc | boks_servm | broker_service | 1026 | bues_service | canit_store | cedros_fds | 1027 | cl/1 | contamac_icm | corel_vncadmin | 1028 | csc_proxy | cvc_hostd | dbcontrol_agent | 1029 | dec_dlm | dl_agent | documentum_s | 1030 | dsmeter_iatc | dsx_monitor | elpro_tunnel | 1031 | elvin_client | elvin_server | encrypted_admin | 1032 | erunbook_agent | erunbook_server | esri_sde | 1033 | EtherNet/IP-1 | EtherNet/IP-2 | event_listener | 1034 | flr_agent | gds_db | ibm_wrless_lan | 1035 | iceedcp_rx | iceedcp_tx | iclcnet_svinfo | 1036 | idig_mux | ife_icorp | instl_bootc | 1037 | instl_boots | intel_rci | interhdl_elmd | 1038 | lan900_remote | LiebDevMgmt_A | LiebDevMgmt_C | 1039 | LiebDevMgmt_DM | mapper-ws_ethd | matrix_vnet | 1040 | mdbs_daemon | menandmice_noh | msl_lmd | 1041 | nburn_id | ncr_ccl | nds_sso | 1042 | netmap_lm | nms_topo_serv | notify_srvr | 1043 | novell-lu6.2 | nuts_bootp | nuts_dem | 1044 | ocs_amu | ocs_cmu | pipe_server | 1045 | pra_elmd | printer_agent | redstorm_diag | 1046 | redstorm_find | redstorm_info | redstorm_join | 1047 | resource_mgr | rmonitor_secure | rsvp_tunnel | 1048 | sai_sentlm | sge_execd | sge_qmaster | 1049 | shiva_confsrvr | sql*net | srvc_registry | 1050 | stm_pproc | subntbcst_tftp | udt_os | 1051 | universe_suite | veritas_pbx | vision_elmd | 1052 | vision_server | wrs_registry | z39.50 | 1053 +----------------+-----------------+-----------------+ 1055 Following the example set by the "application/whoispp-query" MIME 1056 Content-Type [RFC2957], the service name for "whois++" will be 1057 "whoispp". 1059 10.2. Port Numbers for SCTP and DCCP Experimentation 1061 Two Well Known UDP and TCP ports, 1021 and 1022, have been reserved 1062 for experimental use [RFC4727]. This document registers the same 1063 port numbers for SCTP and DCCP, and also instructs IANA to 1064 automatically register these two port numbers for any new transport 1065 protocol that will in the future share the port number namespace. 1067 Note that these port numbers are meant for temporary experimentation 1068 and development in controlled environments. Before using these port 1069 numbers, carefully consider the advice in Section 6.1 in this 1070 document, as well as in Sections 1 and 1.1 of "Assigning Experimental 1071 and Testing Numbers Considered Useful" [RFC3692]. Most importantly, 1072 application developers must request a permanent port number 1073 assignment from IANA as described in Section 8.1 before any kind of 1074 non-experimental deployment. 1076 +-------------------------------------+----------------------------+ 1077 | Registration Administrative Contact | IETF | 1078 | Registration Technical Contact | IESG | 1079 | Service Name | exp1 | 1080 | Port Number | 1021 | 1081 | Transport Protocol | SCTP, DCCP | 1082 | Description | RFC3692-style Experiment 1 | 1083 | Reference | [RFCyyyy] | 1084 +-------------------------------------+----------------------------+ 1086 +-------------------------------------+----------------------------+ 1087 | Registration Administrative Contact | IETF | 1088 | Registration Technical Contact | IESG | 1089 | Service Name | exp2 | 1090 | Port Number | 1022 | 1091 | Transport Protocol | SCTP, DCCP | 1092 | Description | RFC3692-style Experiment 2 | 1093 | Reference | [RFCyyyy] | 1094 +-------------------------------------+----------------------------+ 1096 [RFC Editor Note: Please change "yyyy" to the RFC number allocated to 1097 this document before publication.] 1099 10.3. Updates to DCCP Registries 1101 This document updates the IANA allocation procedures for the DCCP 1102 Port Number and DCCP Service Codes Registries [RFC4340]. 1104 10.3.1. DCCP Service Code Registry 1106 Service Codes are allocated first-come-first-served according to 1107 Section 19.8 of the DCCP specification [RFC4340]. This document 1108 updates that section by extending the guidelines given there in the 1109 following ways: 1111 o IANA MAY assign new Service Codes without seeking Expert Review 1112 using their discretion, but SHOULD seek expert review if a request 1113 seeks more than five Service Codes. 1115 o IANA should feel free to contact the DCCP Expert Reviewer with 1116 questions on any registry, regardless of the registry policy, for 1117 clarification or if there is a problem with a request [RFC4340]. 1119 10.3.2. DCCP Port Numbers Registry 1121 The DCCP ports registry is defined by Section 19.9 of the DCCP 1122 specification [RFC4340]. Allocations in this registry require prior 1123 allocation of a Service Code. Not all Service Codes require IANA- 1124 registered ports. This document updates that section by extending 1125 the guidelines given there in the following way: 1127 o IANA should normally assign a value in the range 1024-49151 to a 1128 DCCP server port. IANA allocation requests to allocate port 1129 numbers in the Well Known Ports range (0 through 1023), require an 1130 "IETF Review" [RFC5226] prior to allocation by IANA [RFC4340]. 1132 o IANA MUST NOT allocate more than one DCCP server port to a single 1133 service code value. 1135 o The allocation of multiple service codes to the same DCCP port is 1136 allowed, but subject to expert review. 1138 o The set of Service Code values associated with a DCCP server port 1139 should be recorded in the ports registry. 1141 o A request for additional Service Codes to be associated with an 1142 already allocated Port Number requires Expert Review. These 1143 requests will normally be accepted when they originate from the 1144 contact associated with the port registration. In other cases, 1145 these applications will be expected to use an unallocated port, 1146 when this is available. 1148 The DCCP specification [RFC4340] notes that a short port name MUST be 1149 associated with each DCCP server port that has been registered. This 1150 document requires that this name MUST be unique. 1152 11. Contributors 1154 Stuart Cheshire (cheshire@apple.com), Alfred Hoenes (ah@tr-sys.de) 1155 and Allison Mankin (mankin@psg.com) have contributed text and ideas 1156 to this document. 1158 12. Acknowledgments 1160 The text in Section 10.3 is based on a suggestion originally proposed 1161 as a part of [RFC5595] by Gorry Fairhurst. 1163 Lars Eggert is partly funded by the Trilogy Project [TRILOGY], a 1164 research project supported by the European Commission under its 1165 Seventh Framework Program. 1167 13. References 1169 13.1. Normative References 1171 [ANSI.X3-4.1986] 1172 American National Standards Institute, "Coded Character 1173 Set - 7-bit American Standard Code for Information 1174 Interchange", ANSI X3.4, 1986. 1176 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, 1177 August 1980. 1179 [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, 1180 RFC 793, September 1981. 1182 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1183 Requirement Levels", BCP 14, RFC 2119, March 1997. 1185 [RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For 1186 Values In the Internet Protocol and Related Headers", 1187 BCP 37, RFC 2780, March 2000. 1189 [RFC3828] Larzon, L-A., Degermark, M., Pink, S., Jonsson, L-E., and 1190 G. Fairhurst, "The Lightweight User Datagram Protocol 1191 (UDP-Lite)", RFC 3828, July 2004. 1193 [RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of 1194 Standards Track Code Points", BCP 100, RFC 4020, 1195 February 2005. 1197 [RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram 1198 Congestion Control Protocol (DCCP)", RFC 4340, March 2006. 1200 [RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, 1201 ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006. 1203 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 1204 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 1205 May 2008. 1207 [RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax 1208 Specifications: ABNF", STD 68, RFC 5234, January 2008. 1210 13.2. Informative References 1212 [I-D.cheshire-dnsext-dns-sd] 1213 Cheshire, S. and M. Krochmal, "DNS-Based Service 1214 Discovery", draft-cheshire-dnsext-dns-sd-06 (work in 1215 progress), March 2010. 1217 [I-D.cheshire-nat-pmp] 1218 Cheshire, S., "NAT Port Mapping Protocol (NAT-PMP)", 1219 draft-cheshire-nat-pmp-03 (work in progress), April 2008. 1221 [I-D.gudmundsson-dnsext-srv-clarify] 1222 Gudmundsson, O. and A. Hoenes, "Clarification of DNS SRV 1223 Owner Names", draft-gudmundsson-dnsext-srv-clarify-00 1224 (work in progress), December 2009. 1226 [IGD] UPnP Forum, "Internet Gateway Device (IGD) V 1.0", 1227 November 2001. 1229 [PORTREG] Internet Assigned Numbers Authority (IANA), "Port Numbers 1230 Registry", http://www.iana.org/assignments/port-numbers. 1232 [PROTSERVREG] 1233 Internet Assigned Numbers Authority (IANA), "Protocol and 1234 Service Names Registry", 1235 http://www.iana.org/assignments/service-names. 1237 [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", 1238 STD 9, RFC 959, October 1985. 1240 [RFC1078] Lottor, M., "TCP port service Multiplexer (TCPMUX)", 1241 RFC 1078, November 1988. 1243 [RFC1700] Reynolds, J. and J. Postel, "Assigned Numbers", RFC 1700, 1244 October 1994. 1246 [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for 1247 specifying the location of services (DNS SRV)", RFC 2782, 1248 February 2000. 1250 [RFC2957] Daigle, L. and P. Faltstrom, "The application/ 1251 whoispp-query Content-Type", RFC 2957, October 2000. 1253 [RFC3232] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by 1254 an On-line Database", RFC 3232, January 2002. 1256 [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers 1257 Considered Useful", BCP 82, RFC 3692, January 2004. 1259 [RFC4342] Floyd, S., Kohler, E., and J. Padhye, "Profile for 1260 Datagram Congestion Control Protocol (DCCP) Congestion 1261 Control ID 3: TCP-Friendly Rate Control (TFRC)", RFC 4342, 1262 March 2006. 1264 [RFC4960] Stewart, R., "Stream Control Transmission Protocol", 1265 RFC 4960, September 2007. 1267 [RFC5237] Arkko, J. and S. Bradner, "IANA Allocation Guidelines for 1268 the Protocol Field", BCP 37, RFC 5237, February 2008. 1270 [RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing, 1271 "Session Traversal Utilities for NAT (STUN)", RFC 5389, 1272 October 2008. 1274 [RFC5595] Fairhurst, G., "The Datagram Congestion Control Protocol 1275 (DCCP) Service Codes", RFC 5595, September 2009. 1277 [RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using 1278 Relays around NAT (TURN): Relay Extensions to Session 1279 Traversal Utilities for NAT (STUN)", RFC 5766, April 2010. 1281 [SRVREG] "DNS SRV Service Types Registry", 1282 http://www.dns-sd.org/ServiceTypes.html. 1284 [SYSFORM] Internet Assigned Numbers Authority (IANA), "Application 1285 for System (Well Known) Port Number", 1286 http://www.iana.org/cgi-bin/sys-port-number.pl. 1288 [TRILOGY] "Trilogy Project", http://www.trilogy-project.org/. 1290 [USRFORM] Internet Assigned Numbers Authority (IANA), "Application 1291 for User (Registered) Port Number", 1292 http://www.iana.org/cgi-bin/usr-port-number.pl. 1294 Authors' Addresses 1296 Michelle Cotton 1297 Internet Corporation for Assigned Names and Numbers 1298 4676 Admiralty Way, Suite 330 1299 Marina del Rey, CA 90292 1300 USA 1302 Phone: +1 310 823 9358 1303 Email: michelle.cotton@icann.org 1304 URI: http://www.iana.org/ 1306 Lars Eggert 1307 Nokia Research Center 1308 P.O. Box 407 1309 Nokia Group 00045 1310 Finland 1312 Phone: +358 50 48 24461 1313 Email: lars.eggert@nokia.com 1314 URI: http://research.nokia.com/people/lars_eggert/ 1316 Joe Touch 1317 USC/ISI 1318 4676 Admiralty Way 1319 Marina del Rey, CA 90292 1320 USA 1322 Phone: +1 310 448 9151 1323 Email: touch@isi.edu 1324 URI: http://www.isi.edu/touch 1326 Magnus Westerlund 1327 Ericsson 1328 Torshamsgatan 23 1329 Stockholm 164 80 1330 Sweden 1332 Phone: +46 8 719 0000 1333 Email: magnus.westerlund@ericsson.com 1334 Stuart Cheshire 1335 Apple Inc. 1336 1 Infinite Loop 1337 Cupertino, CA 95014 1338 USA 1340 Phone: +1 408 974 3207 1341 Email: cheshire@apple.com