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Summary: 4 errors (**), 0 flaws (~~), 5 warnings (==), 6 comments (--). 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, 4340 L. Eggert 5 (if approved) Nokia 6 Intended status: BCP A. Mankin 7 Expires: February 12, 2010 Johns Hopkins Univ. 8 J. Touch 9 USC/ISI 10 M. Westerlund 11 Ericsson 12 August 11, 2009 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-02 18 Status of this Memo 20 This Internet-Draft is submitted to IETF in full conformance with the 21 provisions of BCP 78 and BCP 79. This document may contain material 22 from IETF Documents or IETF Contributions published or made publicly 23 available before November 10, 2008. The person(s) controlling the 24 copyright in some of this material may not have granted the IETF 25 Trust the right to allow modifications of such material outside the 26 IETF Standards Process. Without obtaining an adequate license from 27 the person(s) controlling the copyright in such materials, this 28 document may not be modified outside the IETF Standards Process, and 29 derivative works of it may not be created outside the IETF Standards 30 Process, except to format it for publication as an RFC or to 31 translate it into languages other than English. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF), its areas, and its working groups. Note that 35 other groups may also distribute working documents as Internet- 36 Drafts. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 The list of current Internet-Drafts can be accessed at 44 http://www.ietf.org/ietf/1id-abstracts.txt. 46 The list of Internet-Draft Shadow Directories can be accessed at 47 http://www.ietf.org/shadow.html. 49 This Internet-Draft will expire on February 12, 2010. 51 Copyright Notice 53 Copyright (c) 2009 IETF Trust and the persons identified as the 54 document authors. All rights reserved. 56 This document is subject to BCP 78 and the IETF Trust's Legal 57 Provisions Relating to IETF Documents in effect on the date of 58 publication of this document (http://trustee.ietf.org/license-info). 59 Please review these documents carefully, as they describe your rights 60 and restrictions with respect to this document. 62 Abstract 64 This document defines the procedures that the Internet Assigned 65 Numbers Authority (IANA) uses when handling registration and other 66 requests related to the transport protocol port number and service 67 name registry. It also discusses the rationale and principles behind 68 these procedures and how they facilitate the long-term sustainability 69 of the registry. 71 This document updates RFC2780 by obsoleting Sections 8 and 9.1 of 72 that RFC, and it updates the IANA allocation procedures for DCCP as 73 defined in RFC4340. 75 Table of Contents 77 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 78 2. Conventions Used in this Document . . . . . . . . . . . . . . 5 79 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 80 4. Port Number Ranges . . . . . . . . . . . . . . . . . . . . . . 6 81 4.1. Port Numbers and Service Names for Experimentation . . . . 7 82 5. Principles for Port Number and Service Name Registry 83 Management . . . . . . . . . . . . . . . . . . . . . . . . . . 8 84 5.1. Basic Principles of Port Number Conservation . . . . . . . 9 85 5.2. Variances for Specific Port Number Ranges . . . . . . . . 10 86 5.3. New Principles . . . . . . . . . . . . . . . . . . . . . . 11 87 6. IANA Procedures for Managing the Port Number and Service 88 Name Registry . . . . . . . . . . . . . . . . . . . . . . . . 12 89 6.1. Port Number or Service Name Registration . . . . . . . . . 12 90 6.2. Port Number and Service Name De-Registration . . . . . . . 14 91 6.3. Port Number and Service Name Re-Use . . . . . . . . . . . 14 92 6.4. Port Number and Service Name Revocation . . . . . . . . . 15 93 6.5. Port Number and Service Name Transfers . . . . . . . . . . 15 94 6.6. Maintenance Issues . . . . . . . . . . . . . . . . . . . . 16 95 7. Security Considerations . . . . . . . . . . . . . . . . . . . 16 96 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 97 8.1. Service Name Consistency . . . . . . . . . . . . . . . . . 17 98 8.2. Port Numbers for SCTP and DCCP Experimentation . . . . . . 18 99 8.3. Updates to DCCP Registries . . . . . . . . . . . . . . . . 19 100 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20 101 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21 102 10.1. Normative References . . . . . . . . . . . . . . . . . . . 21 103 10.2. Informative References . . . . . . . . . . . . . . . . . . 21 104 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23 106 1. Introduction 108 The Transmission Control Protocol (TCP) [RFC0793] and the User 109 Datagram Protocol (UDP) [RFC0768] have enjoyed a remarkable success 110 over the decades as the two most widely used transport protocols on 111 the Internet. They have introduced the concept of "ports" as logical 112 entities for Internet communication. Ports serve two purposes: 113 first, they provide a demultiplexing identifier to differentiate 114 transport sessions between the same pair of endpoints, and second, 115 they also identify the application protocol and associated service to 116 which processes bind. Newer transport protocols, such as the Stream 117 Control Transmission Protocol (SCTP) [RFC4960] and the Datagram 118 Congestion Control Protocol (DCCP) [RFC4342] have adopted the concept 119 of ports for their communication sessions and use port numbers in the 120 same way as TCP and UDP. UDP-Lite [RFC3828], a variant of UDP, is 121 also making use of UDP port numbers. For the purposes of this 122 document, all rules stated for UDP also apply to UDP-Lite, because it 123 uses the same assignments as UDP. 125 Port numbers are the original and most widely used means for 126 application and service identification on the Internet. Ports are 127 16-bit numbers, and the combination of source and destination port 128 numbers together with the IP addresses of the communicating end 129 systems uniquely identifies a session of a given transport protocol. 130 Port numbers are also known by their corresponding service names such 131 as "telnet" for port number 23 and both "http" and "www" for port 132 number 80. 134 Hosts running services, hosts accessing services on other hosts, and 135 intermediate devices (such as firewalls and NATs) that restrict 136 services need to agree on which service corresponds to a particular 137 destination port. Although this can be a local decision between the 138 endpoints of a connection, most Internet components use a single, 139 shared view of this association, provided by the Internet Assigned 140 Numbers Authority (IANA) through the port number registry [REGISTRY]. 142 Applications either use numeric port numbers directly, look up port 143 numbers based on service names via system calls such as 144 getservbyname() on UNIX, or - more recently - use service names to 145 look up a service resource records (SRV RRs) [RFC2782] via the Domain 146 Name System (DNS) [RFC1034] in a variety of ways [RFC1078] 147 [I-D.cheshire-dnsext-dns-sd][I-D.cheshire-dnsext-multicastdns] to 148 obtain the port number of a given service. 150 Designers of applications and application-level protocols may apply 151 to IANA for an assigned port number and service name for a specific 152 application, and may - after successful registration - assume that no 153 other application will use that port number and service name for its 154 communication sessions. Alternatively, application designers may 155 also only ask for an assigned service name, if their application does 156 not require a port number. The latter alternative is encouraged when 157 possible, in order to conserve the more limited port number space. 158 It is important to note that ownership of registered port numbers and 159 service names remains with IANA. 161 For protocols developed by IETF working groups, IANA offers a method 162 for the "early" assignment of port numbers and service names, in line 163 with [RFC4020], as described in Section 6.1. 165 This document updates [RFC2780] by obsoleting Sections 8 and 9.1 of 166 that RFC. Note that [RFC5237] updates a different subset of the IANA 167 allocation guidelines originally given in [RFC2780] (specifically, 168 the policies on the namespace of the IP protocol number and IPv6 next 169 header). 171 2. Conventions Used in this Document 173 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 174 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 175 document are to be interpreted as described in BCP 14, RFC 2119 176 [RFC2119]. 178 3. Motivation 180 For many years, the allocation and registration of new port number 181 values and service names for use with TCP and UDP have had less than 182 clear guidelines. Information about the registration procedures for 183 the port registry existed in three locations: the forms for 184 requesting port number registrations on the IANA web site [SYSFORM] 185 [USRFORM], an introductory text section in the file listing the port 186 number registrations themselves [REGISTRY], and two brief sections of 187 [RFC2780]. 189 Similarly, the procedures surrounding service names have been 190 historically unclear. Service names were originally created as 191 mnemonic identifiers for port numbers without a well-defined syntax, 192 beyond the 14-character limit mentioned on the IANA website [SYSFORM] 193 [USRFORM]. (Even that length limit has not been consistently 194 applied, and some assigned service names are 15 characters long.) 195 When service identification via DNS SRV RRs became popular, the 196 ambiguities in the syntactic definition of the service namespace, 197 together with a requirement by IANA to only assign service names and 198 port numbers in combination, led to the creation of an ad-hoc service 199 name registry outside of the control of IANA [SRVTYPE]. 201 This document aggregates this scattered information into a single 202 reference that aligns and clearly defines the management procedures 203 for both port numbers and service names. It gives more detailed 204 guidance to prospective requesters of ports and service names than 205 the existing documentation, and it streamlines the IANA procedures 206 for the management of the registry, so that management requests can 207 complete in a timely manner. It also merges the service name 208 registrations that have occurred in the ad-hoc [SRVTYPE] registry 209 into the IANA registry [REGISTRY], because under the new IANA 210 guidelines, registering service names without port numbers has become 211 possible. 213 A key factor of this procedural streamlining is to establish 214 identical registration procedures for all IETF transport protocols. 215 This document brings the IANA procedures for TCP and UDP in line with 216 those already in effect for SCTP and DCCP, resulting in a single 217 process that requesters and IANA follow for all requests for all 218 transport protocols, including those not yet defined. 220 A second purpose of this document is to describe the principles that 221 guide the IETF and IANA in their role as the long-term joint stewards 222 of the port number registry. TCP and UDP have been a remarkable 223 success over the last decades. Thousands of applications and 224 application-level protocols have registered ports and service names 225 for their use, and there is every reason to believe that this trend 226 will continue into the future. It is hence extremely important that 227 management of the registry follow principles that ensure its long- 228 term usefulness as a shared resource. Section 5 discusses these 229 principles in detail. 231 In addition to detailing the IANA procedures for the initial 232 assignment of port numbers and service names, this document also 233 specifies post-assignment procedures that until now have been handled 234 in an ad-hoc manner. These include procedures to de-register a port 235 number that is no longer in use, to re-use a port number allocated 236 for one application that is no longer in use for another application, 237 and procedure by which IANA can unilaterally revoke a prior port 238 number registration. Section 6 discusses the specifics of these 239 procedures. 241 4. Port Number Ranges 243 TCP, UDP (and UDP-Lite), SCTP and DCCP use 16-bit namespaces for 244 their port number registries. The port registries for all these 245 transport protocols are subdivided into three ranges of numbers, and 246 Section 5.2 describes the IANA procedures for each range in detail: 248 o the Well Known Ports, also known as the System Ports, from 0-1023 249 (assigned by IANA) 251 o the Registered Ports, also known as the User Ports, from 1024- 252 49151 (assigned by IANA) 254 o the Dynamic Ports, also known as the Private Ports, from 49152- 255 65535 (never assigned) 257 Of the assignable port ranges (Well Known and Registered, i.e., port 258 numbers 0-49151), individual port numbers are in one of three states 259 at any given time: 261 o Assigned: Assigned port numbers are currently allocated to the 262 service indicated in the registry. 264 o Unassigned: Unassigned port numbers are currently available for 265 assignment upon request, as per the procedures outlined in this 266 document. 268 o Reserved: Reserved port numbers are not available for regular 269 assignment; they are "assigned to IANA" for special purposes. 270 Reserved port numbers include values at the edges of each range, 271 e.g., 0, 1023, 1024, etc., which may be used to extend these 272 ranges or the overall port number space in the future. 274 In order to keep the size of the registry manageable, IANA typically 275 only records the Assigned and Reserved port numbers and service names 276 in the registry. Unassigned values are typically not explicitly 277 listed. 279 As a data point, when this document was written, approximately 76% of 280 the TCP and UDP Well Known Ports were assigned, as were a significant 281 fraction of the Registered Ports. (As noted, Dynamic Ports are never 282 assigned.) 284 4.1. Port Numbers and Service Names for Experimentation 286 Of the Well Known ports, two TCP and UDP port numbers (1021 and 287 1022), together with their respective service names ("exp1" and 288 "exp2"), have been assigned for experimentation with new applications 289 and application-layer protocols that require a port number in the 290 assigned ports ranges [RFC4727]. This document registers the same 291 two port numbers and service names for experimentation with new 292 application-layer protocols over SCTP and DCCP in Section 8.2. 294 Please refer to Sections 1 and 1.1 of [RFC3692] for how these 295 experimental port numbers are to be used. Specifically, they SHOULD 296 only be used for local experiments in controlled environments, and 297 they SHOULD NOT be used on the global Internet. Many new 298 applications and application-layer protocols can be experimented with 299 without requiring a port in the Well Known or Registered ports range, 300 and port numbers in the Dynamic Ports range can be also used. 302 Unfortunately, it can be difficult to limit access to these ports. 303 Users SHOULD take measures to ensure that experimental ports are 304 connecting to the intended process. For example, users of these 305 experimental ports might include a 64-bit nonce, once on each segment 306 of a message-oriented channel (e.g., UDP), or once at the beginning 307 of a byte-stream (e.g., TCP), which is used to confirm that the port 308 is being used as intended. Such confirmation of intended use is 309 especially important when these ports are associated with privileged 310 (e.g., system or administrator) processes. 312 5. Principles for Port Number and Service Name Registry Management 314 Management procedures for the port number and service name registry 315 include allocation of port numbers and service names upon request, as 316 well as coordination of information about existing allocations. The 317 latter includes maintaining contact and description information about 318 assignments, revoking abandoned assignments, and redefining 319 assignments when needed. Of these procedures, port number allocation 320 is most critical, because of the limited number of remaining port 321 numbers. The namespace available for service names is much larger, 322 which allows for simpler management procedures. 324 Before the publication of this document, the principles of port 325 number and service name management followed some simple, mostly 326 undocumented guidelines: 328 o TCP and UDP ports were simultaneously allocated when either was 329 requested 331 o Port numbers were the primary allocation; service names were 332 informative only, and did not have a well-defined syntax 334 o Port numbers were conserved informally, and sometimes 335 inconsistently (e.g., some services were allocated ranges of many 336 port numbers even where not strictly necessary) 338 o SCTP and DCCP port number and service name registries were managed 339 separately from the TCP/UDP registries 341 o Until recently, service names could not be assigned without 342 assigning a corresponding port number 344 This document attempts to document, clarify and align these 345 guidelines in order to more conservatively manage the limited 346 remaining port number space and to enable and promote the use of 347 service names for service identification without associated port 348 numbers, where possible. 350 5.1. Basic Principles of Port Number Conservation 352 This section summarizes the basic principles by which IANA attempts 353 to conserve the port number space. This description is intended to 354 inform applicants requesting port numbers. IANA decisions are not 355 required to be bound to these principles, however; other factors may 356 come into play, and exceptions may occur where deemed in the best 357 interest of the Internet. 359 The basic principle of port number registry management is to conserve 360 use of the port space where possible. Extensions to support larger 361 port number spaces would require changing many core protocols of the 362 current Internet in a way that would not be backward compatible and 363 interfere with both current and legacy applications. 365 Conservation of the port number space recognizes that because this 366 space is a limited resource, applications are expected to participate 367 in the traffic demultiplexing process where feasible. The port 368 numbers are expected to encode as little information as possible that 369 will still enable an application to perform further demultiplexing by 370 itself. In particular, there should be: 372 o only one assigned port number per service or application 374 o only one assigned port number for all versions of a service (e.g., 375 running the service with or without a security mechanism) 377 o only one assigned port number for all different types of devices 378 using or participating in the same service 380 A given service is expected to further demultiplex messages where 381 possible. For example, applications and protocols are expected to 382 include in-band version information, so that future versions of the 383 application or protocol can share the same allocated port. 384 Applications and protocols are also expected to be able to 385 efficiently use a single allocated port for multiple sessions, either 386 by demultiplexing multiple streams within one port, or using the 387 allocated port to coordinate using dynamic ports for subsequent 388 exchanges (e.g., in the spirit of FTP [RFC0959]). 390 Ports are used in various ways, notably: 392 o as endpoint process identifiers 394 o as application protocol identifiers 396 o for firewall filtering purposes 398 The process and protocol identifier use suggests that anything a 399 single process can demultiplex, or that can be encoded into a single 400 protocol, should be. The firewall filtering use suggests that some 401 uses that could be de-multiplexed or encoded must be separated to 402 allow for firewall management. Note that this latter use is much 403 less sound, because port numbers have meaning only for the two 404 endpoints involved in a connection, and drawing conclusions about the 405 service that generated a given flow based on observed port numbers is 406 inherently problematic. 408 5.2. Variances for Specific Port Number Ranges 410 Section 4 describes the different port number ranges. It is 411 important to note that IANA applies slightly different procedures 412 when managing the different ranges of the port number registry: 414 o Ports in the Dynamic Ports range (49152-65535) have been 415 specifically set aside for local and dynamic use and cannot be 416 registered through IANA. Applications may simply use them for 417 communication without any sort of registration. On the other 418 hand, applications MUST NOT assume that a specific port number in 419 the Dynamic Ports range will always be available for communication 420 at all times, and a port number in that range hence MUST NOT be 421 used as a service identifier. 423 o Ports in the Registered Ports range (1024-49151) are available for 424 registration through IANA, and MAY be used as service identifiers 425 upon successful registration. Because registering a port number 426 for a specific application consumes a fraction of the shared 427 resource that is the port number registry, IANA will require the 428 requester to document the intended use of the port number. This 429 documentation will be input to the "Expert Review" allocation 430 procedure [RFC5226], by which IANA will have a technical expert 431 review the request to determine whether to grant the registration. 432 The submitted documentation MUST explain why using a port number 433 in the Dynamic Ports range is unsuitable for the given 434 application. 436 o Ports in the Well Known Ports range (0-1023) are also available 437 for registration through IANA. Because the Well Known Ports range 438 is both the smallest and the most densely allocated one, the bar 439 for new allocations is higher than that for the Registered Ports 440 range, and will only be granted under the "IETF Review" allocation 441 procedure [RFC5226]. A request for a Well Known port number MUST 442 document why using a port number from both the Registered Ports 443 and Dynamic Ports ranges is unsuitable for the given application. 445 5.3. New Principles 447 Several new practices stem from the conservation principle that 448 guides management of the port number and service name registry, and 449 will take effect with the approval of this document: 451 o IANA will allocate port numbers only to the transport protocols 452 explicitly named in an allocation request 454 o IANA will recover unused port numbers, via the new procedures of 455 de-registration, revocation, and transfer 457 o IANA will begin assigning service names without requiring a 458 corresponding port number allocation 460 IANA will begin assigning protocol numbers only for those transport 461 protocols explicitly included in a registration request. This ends 462 the long-standing practice of automatically assigning a port number 463 to an application for both TCP and a UDP, even if the request is only 464 for one of these transport protocols. The new allocation procedure 465 conserves resources by only allocating a port number to an 466 application for those transport protocols (TCP, UDP, SCTP and/or 467 DCCP) it actually uses. The port number will be marked as Reserved - 468 instead of Assigned - in the port number registries of the other 469 transport protocols. When applications start supporting the use of 470 some of those additional transport protocols, their implementors MUST 471 request IANA to convert the reservation into an assignment. An 472 application MUST NOT assume that it can use a port number assigned to 473 it for use with one transport protocol with another transport 474 protocol without asking IANA to convert the reservation into an 475 assignment. 477 Conservation of port numbers is improved by procedures that allow 478 previously allocated port numbers to become Unassigned, either 479 through de-registration or through revocation, and by a procedure 480 that lets application designers transfer an allocated but unused port 481 number to a new application. Section 6 describes these procedures, 482 which so far were undocumented. Port number conservation is also 483 improved by recommending that applications that do not require an 484 allocated port, e.g., because they can use service-name-based 485 lookups, chose this option and only register a service name. 487 6. IANA Procedures for Managing the Port Number and Service Name 488 Registry 490 This section describes the process for requests associated with 491 IANA's management of the port number and service name registry. Such 492 requests include initial registration, de-registration, re-use, 493 changes to the service name, as well as updates to the contact 494 information or description associated with an assignment. Revocation 495 is initiated by IANA. 497 6.1. Port Number or Service Name Registration 499 Registration refers to the allocation of port numbers or service 500 names to applicants. All such, registrations are made from port 501 numbers or service names that are Unassigned or Reserved at the time 502 of the allocation. Unassigned numbers and names are allocated as 503 needed, and without further explanation. Reserved numbers and names 504 are assigned only after review by IANA and the IETF, and are 505 accompanied by a statement explaining the reason a Reserved number or 506 name is appropriate for this action. 508 When a registration for one or more (but not all) transport protocols 509 is approved, the port number for the non-requested transport 510 protocol(s) will be marked as Reserved. IANA SHOULD NOT assign that 511 port number to any other application or service until no other port 512 numbers remain Unassigned in the requested range. The current 513 registration owner of a port number MAY register these Reserved port 514 numbers for other transport protocols when needed. 516 Service names, on the other hand, are not tied to a specific 517 transport protocol, and registration requests for only a service name 518 (but not a port number) allocate that service name for use with all 519 transport protocols. 521 A port number or service name registration consists of the following 522 information: 524 o Registration Technical Contact: Name and email address of the 525 technical contact person for the registration. This is REQUIRED. 526 Additional address information MAY be provided. For registrations 527 done through IETF-published RFCs, one or more technical contact 528 persons SHALL be provided. 530 o Registration Owner: Name and email address of the owner of the 531 registration. This is REQUIRED. For individuals, this is the 532 same as the registration technical contact; for organizations, 533 this is a point of contact at that organization. For 534 registrations done through IETF-published RFCs, the registration 535 ownership will belong to the IETF and not the technical contact 536 persons. 538 o Transport Protocol: The transport protocol(s) for which the port 539 number or service name allocation is requested MUST be provided. 540 This field is currently limited to one or more of TCP, UDP, SCTP, 541 and DCCP. 543 o Port Number: If assignment of port number(s) is desired, either 544 the currently Unassigned port number(s) the requester suggests for 545 allocation or the tag "ANY" MUST be provided. If only a service 546 name is to be assigned, this field MUST be empty. If specific 547 port numbers are requested, IANA is encouraged to allocate the 548 suggested numbers. If the tag "ANY" is specified, IANA will 549 choose a suitable number from the Registered Ports range. Note 550 that the applicant MUST NOT use the suggested ports prior to the 551 completion of the registration. 553 o Service Name: A desired unique service name for the service 554 associated with the registration request, for use in various 555 service selection and discovery mechanisms, MUST be provided. 556 Valid service names MUST only contain these US-ASCII 557 [ANSI.X3-4.1986] characters: letters from A to Z, digits from 0 to 558 9, and hyphens ("-", ASCII 0x2D or decimal 45). They MUST be at 559 MOST fifteen characters long, MUST NOT begin or end with a hyphen, 560 and MUST NOT consist of only digits, in order to be 561 distinguishable from port numbers. In order to be unique, they 562 MUST NOT be identical to any currently registered service names in 563 the IANA registry [REGISTRY]. Service names are case-insensitive; 564 they may be provided and entered into the registry with mixed case 565 (e.g., for clarity), but for the purposes of comparison, the case 566 is ignored. 568 o Service Code: A desired unique service code for the service 569 associated with the registration request. Service codes are 570 specific to the DCCP protocol [I-D.ietf-dccp-serv-codes]; the 571 request MUST include a desired service code when the registration 572 requests includes DCCP as a transport protocol, and MUST NOT 573 include one otherwise. 575 o Description: A short description of the service associated with 576 the registration request is REQUIRED. It should avoid all but the 577 most well known acronyms. 579 o Reference: A reference document describing the protocol or 580 application using this port, including whether the protocol 581 supports either broadcast, multicast, or anycast communication. 582 For registration requests for Registered Ports, this documentation 583 MUST explain why a port number in the Dynamic Ports range is 584 unsuitable for the given application. For registration requests 585 for Well Known Ports, this documentation MUST explain why a port 586 number in the Registered Ports or Dynamic Ports ranges is 587 unsuitable. 589 "Early" registration requests can be made by IETF working groups 590 without including such a reference document, although it is 591 RECOMMENDED that at least a reference to an Internet Draft 592 describing the work in progress is provided. 594 6.2. Port Number and Service Name De-Registration 596 The original requesters of a granted port number assignment can 597 return the port number to IANA at any time if they no longer have a 598 need for it. The port number will be de-registered and will be 599 marked as Reserved. IANA should not re-assign port numbers that have 600 been de-registered until all other available port numbers in the 601 specific range have been assigned. 603 Before proceeding with a port number de-registration, IANA needs to 604 reasonably establish that the value is actually no longer in use. 606 Because there is much less danger of exhausting the service name 607 space compared to the port number space, it is RECOMMENDED that a 608 given service name remain assigned even after all associated port 609 number assignments have become de-registered. It will afterwards 610 appear in the registry as if it had been created through a service 611 name registration request that did not include any port numbers. 613 On rare occasions, it may still be useful to de-register a service 614 name. In such cases, IANA will mark the service name as Reserved. 616 6.3. Port Number and Service Name Re-Use 618 If the original requesters of a granted port number assignment no 619 longer have a need for the registered number, but would like to re- 620 use it for a different application, they can submit a request to IANA 621 to do so. 623 Logically, port number re-use is to be thought of as a de- 624 registration (Section 6.2) followed by an immediate re-registration 625 (Section 6.1) of the same port number for a new application. 626 Consequently, the information that needs to be provided about the 627 proposed new use of the port number is identical to what would need 628 to be provided for a new port number allocation for the specific 629 ports range. 631 Because there is much less danger of exhausting the service name 632 space compared to the port number space, it is RECOMMENDED that the 633 original service name associated with the prior use of the port 634 number remains assigned, and a new service be created and associated 635 with the port number. This is again consistent with viewing a re-use 636 request as a de-registration followed by an immediate re- 637 registration. Re-using an assigned service name for a different 638 application is NOT RECOMMENDED. 640 IANA needs to carefully review such requests before approving them. 641 In some instances, the Expert Reviewer will determine that the 642 application that the port number was assigned to has found usage 643 beyond the original requester, or that there is a concern that it may 644 have such users. This determination MUST be made quickly. A 645 community call concerning revocation of a port number (see below) MAY 646 be considered, if a broader use of the port number is suspected. 648 6.4. Port Number and Service Name Revocation 650 A port number revocation can be thought of as an IANA-initiated de- 651 registration (Section 6.2), and has exactly the same effect on the 652 registry. 654 Sometimes, it will be clear that a specific port number is no longer 655 in use and that IANA can revoke it and mark it as Reserved. At other 656 times, it may be unclear whether a given assigned port number is 657 still in use somewhere in the Internet. In those cases, IANA must 658 carefully consider the consequences of revoking the port number, and 659 SHOULD only do so if there is an overwhelming need. 661 With the help of their IESG-appointed Expert Reviewer, IANA SHALL 662 formulate a request to the IESG to issue a four-week community call 663 concerning the pending port number revocation. The IESG and IANA, 664 with the Expert Reviewer's support, SHALL determine promptly after 665 the end of the community call whether revocation should proceed and 666 then communicate their decision to the community. This procedure 667 typically involves similar steps to de-registration except that it is 668 initiated by IANA. 670 Because there is much less danger of exhausting the service name 671 space compared to the port number space, revoking service names is 672 NOT RECOMMENDED. 674 6.5. Port Number and Service Name Transfers 676 The value of port numbers and service names is defined by their 677 careful management as a shared Internet resource, whereas enabling 678 transfer allows the potential for associated monetary exchanges. As 679 a result, current IANA procedures do not permit port number or 680 service name assignments to be transferred between parties, even when 681 they are mutually consenting. 683 The appropriate alternate procedure is a coordinated de-registration 684 and registration: The new party requests the port number or service 685 name via a registration and the previous party releases its 686 assignment via the de-registration procedure outlined above. 688 With the help of their IESG-appointed Expert Reviewer, IANA SHALL 689 carefully determine if there is a valid technical, operational or 690 managerial reason before performing the transfer. 692 6.6. Maintenance Issues 694 The previous procedures help IANA manage the defining properties of 695 the port name and service name registry. There are additional 696 procedures which are administrative and help IANA maintain non- 697 defining information in a registration. This includes changes to the 698 Port Description and changes to contact information. These changes 699 are coordinated by IANA in an informal manner, and may be initiated 700 by either the registrant or by IANA, e.g., the latter when requesting 701 an update to current contact information. 703 7. Security Considerations 705 The IANA guidelines described in this document do not change the 706 security properties of either TCP, SCTP, DCCP or UDP. 708 Assignment of a port number or service name does not in any way imply 709 an endorsement of an application or product, and the fact that 710 network traffic is flowing to or from a registered port number does 711 not mean that it is "good" traffic, or even that it is used by the 712 assigned service. Firewall and system administrators should choose 713 how to configure their systems based on their knowledge of the 714 traffic in question, not whether there is a port number or service 715 name registered or not. 717 8. IANA Considerations 719 This document obsoletes Sections 8 and 9.1 of [RFC2780]. Upon 720 approval of this document, IANA is requested to adopt the procedures 721 described herein. 723 8.1. Service Name Consistency 725 Section 6.1 defines which character strings are well-formed service 726 names, which until now had not been clearly defined. The definition 727 on Section 6.1 was chosen to allow maximum compatibility of service 728 names with various service discovery mechanisms. 730 Unfortunately, the current port number registry [REGISTRY] contains a 731 few assigned service names that do not conform to the new naming 732 rules. In all cases, this is because they contain illegal characters 733 such as asterisks, dots, plusses, slashes, or underscores. (All 734 current service names conform to the length requirement of 15 735 characters or less.) 737 Upon approval of this document, IANA SHALL take immediate actions to 738 resolve these inconsistencies. For any registry assignment with an 739 illegal service name, IANA SHALL add an alias to the registry that 740 assigns a well-formed service name for the existing service but 741 otherwise duplicates the original assignment information. It is 742 desirable if the alias closely resembles the original service name, 743 e.g., by remapping underscores to dashes, etc. In the description 744 field of the new alias, IANA SHALL record that it assigns a well- 745 formed service name for the previous service and point to the 746 original assignment. In the description field of the original 747 assignment, IANA SHALL add a note that the service name is historic, 748 is not usable with many common service discovery mechanisms, and 749 provide a reference to the new alias, which can be used in this way. 751 As of 2009-8-5 [REGISTRY], these service names were illegal under the 752 rules stated in Section 6.1: 754 +-----------------+-----------------+----------------+ 755 | 914c/g | EtherNet/IP-1 | EtherNet/IP-2 | 756 | LiebDevMgmt_A | LiebDevMgmt_C | LiebDevMgmt_DM | 757 | acmaint_dbd | acmaint_transd | atex_elmd | 758 | avanti_cdp | badm_priv | badm_pub | 759 | bdir_priv | bdir_pub | bmc_ctd_ldap | 760 | bmc_patroldb | boks_clntd | boks_servc | 761 | boks_servm | broker_service | bues_service | 762 | canit_store | cedros_fds | cl/1 | 763 | contamac_icm | corel_vncadmin | csc_proxy | 764 | cvc_hostd | dbcontrol_agent | dec_dlm | 765 | dl_agent | documentum_s | dsmeter_iatc | 766 | dsx_monitor | elpro_tunnel | elvin_client | 767 | elvin_server | encrypted_admin | erunbook_agent | 768 | erunbook_server | esri_sde | event_listener | 769 | flr_agent | gds_db | ibm_wrless_lan | 770 | iceedcp_rx | iceedcp_tx | iclcnet_svinfo | 771 | idig_mux | ife_icorp | instl_bootc | 772 | instl_boots | intel_rci | interhdl_elmd | 773 | lan900_remote | mapper-ws_ethd | matrix_vnet | 774 | mdbs_daemon | menandmice_noh | msl_lmd | 775 | nburn_id | ncr_ccl | nds_sso | 776 | netmap_lm | nms_topo_serv | notify_srvr | 777 | novell-lu6.2 | nuts_bootp | nuts_dem | 778 | ocs_amu | ocs_cmu | pipe_server | 779 | pra_elmd | printer_agent | redstorm_diag | 780 | redstorm_find | redstorm_info | redstorm_join | 781 | resource_mgr | rmonitor_secure | rsvp_tunnel | 782 | sai_sentlm | sge_execd | sge_qmaster | 783 | shiva_confsrvr | srvc_registry | stm_pproc | 784 | subntbcst_tftp | udt_os | universe_suite | 785 | veritas_pbx | vision_elmd | vision_server | 786 | whois++ | wrs_registry | z39.50 | 787 +-----------------+-----------------+----------------+ 789 8.2. Port Numbers for SCTP and DCCP Experimentation 791 Two Well Known ports, 1021 and 1022, have been reserved for 792 experimentation UDP and TCP [RFC4727]. This document registers the 793 same port numbers for SCTP and DCCP, and also instructs IANA to 794 automatically register these two port numbers for any new transport 795 protocol that will in the future share the port number namespace. 797 Note that these port numbers are meant for temporary experimentation 798 and development in controlled environments. Before using these port 799 numbers, carefully consider the advice in Section 4.1 in this 800 document, as well as in Sections 1 and 1.1 of [RFC3692]. Most 801 importantly, application developers must request a permanent port 802 number assignment from IANA as described in Section 6.1 before any 803 kind of non-experimental deployment. 805 +--------------------------------+----------------------------+ 806 | Registration Technical Contact | IESG | 807 | Registration Owner | IETF | 808 | Transport Protocol | SCTP, DCCP | 809 | Port Number | 1021 | 810 | Port Name | RFC3692-style Experiment 1 | 811 | Service Name | exp1 | 812 | Reference | [RFCyyyy] | 813 +--------------------------------+----------------------------+ 815 +--------------------------------+----------------------------+ 816 | Registration Technical Contact | IESG | 817 | Registration Owner | IETF | 818 | Transport Protocol | SCTP, DCCP | 819 | Port Number | 1022 | 820 | Port Name | RFC3692-style Experiment 2 | 821 | Service Name | exp2 | 822 | Reference | [RFCyyyy] | 823 +--------------------------------+----------------------------+ 825 [RFC Editor Note: Please change "yyyy" to the RFC number allocated to 826 this document before publication.] 828 8.3. Updates to DCCP Registries 830 This document updates the IANA allocation procedures for the DCCP 831 Port Number and DCCP Service Codes Registries as defined in 832 [RFC4340]. 834 8.3.1. DCCP Service Code Registry 836 Service Codes are allocated first-come-first-served according to 837 Section 19.8 of [RFC4340]. This document updates Section 19.8 of 838 [RFC4340] by extending the guidelines given there in the following 839 ways: 841 o IANA MAY assign new Service Codes without seeking Expert Review 842 using their discretion, but SHOULD seek expert review when a 843 request seeks an appreciable number of Service Codes (e.g., more 844 than five). 846 o IANA should feel free to contact the DCCP Expert Reviewer with 847 questions on any registry, regardless of the registry policy, for 848 clarification or if there is a problem with a request [RFC4340]. 850 8.3.2. DCCP Port Numbers Registry 852 The DCCP ports registry is defined by [RFC4340] in Section 19.9. 853 Allocations in this registry require prior allocation of a Service 854 Code. Not all Service Codes require IANA-registered ports. This 855 document updates Section 19.9 of [RFC4340] by extending the 856 guidelines given there in the following way: 858 o IANA should normally assign a value in the range 1024-49151 to a 859 DCCP server port. IANA allocation requests to allocate port 860 numbers in the Well Known Ports range (0 through 1023), require an 861 "IETF Review" [RFC5226] prior to allocation by IANA [RFC4340]. 863 Section 19.9 of [RFC4340] requires each DCCP server port assignment 864 to be associated with at least one Service Code value. This document 865 updates [RFC4340] in the following way: 867 o IANA MUST NOT allocate a single Service Code value to more than 868 one DCCP server port. 870 o The set of Service Code values associated with a DCCP server port 871 should be recorded in the ports registry. 873 o A request for additional Service Codes to be associated with an 874 already allocated Port Number requires Expert Review. These 875 requests will normally be accepted when they originate from the 876 contact associated with the port registration. In other cases, 877 these applications will be expected to use an unallocated port, 878 when this is available. 880 [RFC4340] notes that a short port name MUST be associated with each 881 DCCP server port that has been registered. This document requires 882 that this name MUST be unique. 884 9. Acknowledgments 886 The text in Section 8.3 is based on a suggestion by Tom Phelan. 888 Lars Eggert is partly funded by [TRILOGY], a research project 889 supported by the European Commission under its Seventh Framework 890 Program. 892 10. References 893 10.1. Normative References 895 [ANSI.X3-4.1986] 896 American National Standards Institute, "Coded Character 897 Set - 7-bit American Standard Code for Information 898 Interchange", ANSI X3.4, 1986. 900 [RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768, 901 August 1980. 903 [RFC0793] Postel, J., "Transmission Control Protocol", STD 7, 904 RFC 793, September 1981. 906 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 907 Requirement Levels", BCP 14, RFC 2119, March 1997. 909 [RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For 910 Values In the Internet Protocol and Related Headers", 911 BCP 37, RFC 2780, March 2000. 913 [RFC3828] Larzon, L-A., Degermark, M., Pink, S., Jonsson, L-E., and 914 G. Fairhurst, "The Lightweight User Datagram Protocol 915 (UDP-Lite)", RFC 3828, July 2004. 917 [RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of 918 Standards Track Code Points", BCP 100, RFC 4020, 919 February 2005. 921 [RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram 922 Congestion Control Protocol (DCCP)", RFC 4340, March 2006. 924 [RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4, 925 ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006. 927 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 928 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 929 May 2008. 931 10.2. Informative References 933 [I-D.cheshire-dnsext-dns-sd] 934 Cheshire, S. and M. Krochmal, "DNS-Based Service 935 Discovery", draft-cheshire-dnsext-dns-sd-05 (work in 936 progress), September 2008. 938 [I-D.cheshire-dnsext-multicastdns] 939 Cheshire, S. and M. Krochmal, "Multicast DNS", 940 draft-cheshire-dnsext-multicastdns-07 (work in progress), 941 September 2008. 943 [I-D.ietf-dccp-serv-codes] 944 Fairhurst, G., "The DCCP Service Code", 945 draft-ietf-dccp-serv-codes-11 (work in progress), 946 May 2009. 948 [REGISTRY] 949 Internet Assigned Numbers Authority (IANA), "Port 950 Numbers", http://www.iana.org/assignments/port-numbers. 952 [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", 953 STD 9, RFC 959, October 1985. 955 [RFC1034] Mockapetris, P., "Domain names - concepts and facilities", 956 STD 13, RFC 1034, November 1987. 958 [RFC1078] Lottor, M., "TCP port service Multiplexer (TCPMUX)", 959 RFC 1078, November 1988. 961 [RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for 962 specifying the location of services (DNS SRV)", RFC 2782, 963 February 2000. 965 [RFC3692] Narten, T., "Assigning Experimental and Testing Numbers 966 Considered Useful", BCP 82, RFC 3692, January 2004. 968 [RFC4342] Floyd, S., Kohler, E., and J. Padhye, "Profile for 969 Datagram Congestion Control Protocol (DCCP) Congestion 970 Control ID 3: TCP-Friendly Rate Control (TFRC)", RFC 4342, 971 March 2006. 973 [RFC4960] Stewart, R., "Stream Control Transmission Protocol", 974 RFC 4960, September 2007. 976 [RFC5237] Arkko, J. and S. Bradner, "IANA Allocation Guidelines for 977 the Protocol Field", BCP 37, RFC 5237, February 2008. 979 [SRVTYPE] "DNS SRV (RFC 2782) Service Types", 980 http://www.dns-sd.org/ServiceTypes.html. 982 [SYSFORM] Internet Assigned Numbers Authority (IANA), "Application 983 for System (Well Known) Port Number", 984 http://www.iana.org/cgi-bin/sys-port-number.pl. 986 [TRILOGY] "Trilogy Project", http://www.trilogy-project.org/. 988 [USRFORM] Internet Assigned Numbers Authority (IANA), "Application 989 for User (Registered) Port Number", 990 http://www.iana.org/cgi-bin/usr-port-number.pl. 992 Authors' Addresses 994 Michelle Cotton 995 Internet Corporation for Assigned Names and Numbers 996 4676 Admiralty Way, Suite 330 997 Marina del Rey, CA 90292 998 USA 1000 Phone: +1 310 823 9358 1001 Email: michelle.cotton@icann.org 1002 URI: http://www.iana.org/ 1004 Lars Eggert 1005 Nokia Research Center 1006 P.O. Box 407 1007 Nokia Group 00045 1008 Finland 1010 Phone: +358 50 48 24461 1011 Email: lars.eggert@nokia.com 1012 URI: http://research.nokia.com/people/lars_eggert/ 1014 Allison Mankin 1015 Johns Hopkins University 1017 Phone: +1 301 728 7199 1018 Email: mankin@psg.com 1019 URI: http://www.psg.com/~mankin/ 1021 Joe Touch 1022 USC/ISI 1023 4676 Admiralty Way 1024 Marina del Rey, CA 90292 1025 USA 1027 Phone: +1 310 448 9151 1028 Email: touch@isi.edu 1029 URI: http://www.isi.edu/touch 1030 Magnus Westerlund 1031 Ericsson 1032 Torshamsgatan 23 1033 Stockholm 164 80 1034 Sweden 1036 Phone: +46 8 719 0000 1037 Email: magnus.westerlund@ericsson.com