draft-ietf-tsvwg-iana-ports-06.txt   draft-ietf-tsvwg-iana-ports-07.txt 
Transport Area Working Group M. Cotton Transport Area Working Group M. Cotton
Internet-Draft ICANN Internet-Draft ICANN
Updates: 2780, 2782, 3828, 4340, L. Eggert Updates: 2780, 2782, 3828, 4340, L. Eggert
4960 (if approved) Nokia 4960 (if approved) Nokia
Intended status: BCP J. Touch Intended status: BCP J. Touch
Expires: November 27, 2010 USC/ISI Expires: April 15, 2011 USC/ISI
M. Westerlund M. Westerlund
Ericsson Ericsson
S. Cheshire S. Cheshire
Apple Apple
May 26, 2010 October 12, 2010
Internet Assigned Numbers Authority (IANA) Procedures for the Management Internet Assigned Numbers Authority (IANA) Procedures for the Management
of the Transport Protocol Port Number and Service Name Registry of the Service Name and Transport Protocol Port Number Registry
draft-ietf-tsvwg-iana-ports-06 draft-ietf-tsvwg-iana-ports-07
Abstract Abstract
This document defines the procedures that the Internet Assigned This document defines the procedures that the Internet Assigned
Numbers Authority (IANA) uses when handling registration and other Numbers Authority (IANA) uses when handling registration and other
requests related to the transport protocol port number and service requests related to the Service Name and Transport Protocol Port
name registry. It also discusses the rationale and principles behind Number Registry. It also discusses the rationale and principles
these procedures and how they facilitate the long-term sustainability behind these procedures and how they facilitate the long-term
of the registry. sustainability of the registry.
This document updates IANA's procedures by obsoleting Sections 8 and This document updates IANA's procedures by obsoleting Sections 8 and
9.1 of the IANA allocation guidelines [RFC2780], it updates the IANA 9.1 of the IANA allocation guidelines [RFC2780], and it updates the
allocation procedures for UDP-Lite [RFC3828], DCCP [RFC4340] and SCTP IANA allocation procedures for UDP-Lite [RFC3828], DCCP [RFC4340] and
[RFC4960], it updates the DNS SRV specification [RFC2782] to clarify SCTP [RFC4960]. It also updates the DNS SRV specification [RFC2782]
what a service name is and how it is registered. to clarify what a service name is and how it is registered.
Status of this Memo Status of this Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 27, 2010. This Internet-Draft will expire on April 15, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 3, line 13 skipping to change at page 3, line 13
than English. than English.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Conventions Used in this Document . . . . . . . . . . . . . . 7 4. Conventions Used in this Document . . . . . . . . . . . . . . 7
5. Service Names . . . . . . . . . . . . . . . . . . . . . . . . 8 5. Service Names . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Service Name Syntax . . . . . . . . . . . . . . . . . . . 9 5.1. Service Name Syntax . . . . . . . . . . . . . . . . . . . 9
5.2. Service Name Usage in DNS SRV Records . . . . . . . . . . 9 5.2. Service Name Usage in DNS SRV Records . . . . . . . . . . 10
6. Port Number Ranges . . . . . . . . . . . . . . . . . . . . . . 10 6. Port Number Ranges . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Port Numbers and Service Names for Experimentation . . . . 11 6.1. Service names and Port Numbers for Experimentation . . . . 11
7. Principles for Port Number and Service Name Registry 7. Principles for Service Name and Transport Protocol Port
Management . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Number Registry Management . . . . . . . . . . . . . . . . . . 12
7.1. Past Principles . . . . . . . . . . . . . . . . . . . . . 12 7.1. Past Principles . . . . . . . . . . . . . . . . . . . . . 12
7.2. Updated Principles . . . . . . . . . . . . . . . . . . . . 12 7.2. Updated Principles . . . . . . . . . . . . . . . . . . . . 13
7.3. Variances for Specific Port Number Ranges . . . . . . . . 15 8. IANA Procedures for Managing the Service Name and
8. IANA Procedures for Managing the Port Number and Service Transport Protocol Port Number Registry . . . . . . . . . . . 15
Name Registry . . . . . . . . . . . . . . . . . . . . . . . . 16 8.1. Service Name and Port Number Registration . . . . . . . . 15
8.1. Port Number and Service Name Registration . . . . . . . . 16 8.2. Service Name and Port Number De-Registration . . . . . . . 20
8.2. Port Number and Service Name De-Registration . . . . . . . 19 8.3. Service Name and Port Number Re-Use . . . . . . . . . . . 20
8.3. Port Number and Service Name Re-Use . . . . . . . . . . . 19 8.4. Service Name and Port Number Revocation . . . . . . . . . 21
8.4. Port Number and Service Name Revocation . . . . . . . . . 20 8.5. Service Name and Port Number Transfers . . . . . . . . . . 21
8.5. Port Number and Service Name Transfers . . . . . . . . . . 21 8.6. Maintenance Issues . . . . . . . . . . . . . . . . . . . . 22
8.6. Maintenance Issues . . . . . . . . . . . . . . . . . . . . 21 8.7. Disagreements . . . . . . . . . . . . . . . . . . . . . . 22
9. Security Considerations . . . . . . . . . . . . . . . . . . . 21 9. Security Considerations . . . . . . . . . . . . . . . . . . . 22
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
10.1. Service Name Consistency . . . . . . . . . . . . . . . . . 22 10.1. Service Name Consistency . . . . . . . . . . . . . . . . . 23
10.2. Port Numbers for SCTP and DCCP Experimentation . . . . . . 24 10.2. Port Numbers for SCTP and DCCP Experimentation . . . . . . 25
10.3. Updates to DCCP Registries . . . . . . . . . . . . . . . . 25 10.3. Updates to DCCP Registries . . . . . . . . . . . . . . . . 26
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 26 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 27
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26 12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 27
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 28
13.1. Normative References . . . . . . . . . . . . . . . . . . . 27 13.1. Normative References . . . . . . . . . . . . . . . . . . . 28
13.2. Informative References . . . . . . . . . . . . . . . . . . 28 13.2. Informative References . . . . . . . . . . . . . . . . . . 29
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 30
1. Introduction 1. Introduction
For many years, the allocation and registration of new port number For many years, the allocation of new service names and port number
values and service names for use with the Transmission Control values for use with the Transmission Control Protocol (TCP) [RFC0793]
Protocol (TCP) [RFC0793] and the User Datagram Protocol (UDP) and the User Datagram Protocol (UDP) [RFC0768] have had less than
[RFC0768] have had less than clear guidelines. New transport clear guidelines. New transport protocols have been added - the
protocols have been added - the Stream Control Transmission Protocol Stream Control Transmission Protocol (SCTP) [RFC4960] and the
(SCTP) [RFC4960] and the Datagram Congestion Control Protocol (DCCP) Datagram Congestion Control Protocol (DCCP) [RFC4342] - and new
[RFC4342] - and new mechanisms like DNS SRV records [RFC2782] have mechanisms like DNS SRV records [RFC2782] have been developed, each
been developed, each with separate registries and separate with separate registries and separate guidelines. The community also
guidelines. The community recognized the need for additional recognized the need for additional procedures beyond just assignment;
procedures beyond just assignment; notably modification, revocation, notably modification, revocation, and release.
and release.
A key factor of this procedural streamlining is to establish A key element of the procedural streamlining specified in this
identical registration procedures for all IETF transport protocols. document is to establish identical assignment procedures for all IETF
This document brings the IANA procedures for TCP and UDP in line with transport protocols. This document brings the IANA procedures for
those for SCTP and DCCP, resulting in a single process that TCP and UDP in line with those for SCTP and DCCP, resulting in a
requesters and IANA follow for all requests for all transport single process that requesters and IANA follow for all requests for
protocols, including those not yet defined. all transport protocols, including future protocols not yet defined.
In addition to detailing the IANA procedures for the initial In addition to detailing the IANA procedures for the initial
assignment of port numbers and service names, this document also assignment of service names and port numbers, this document also
specifies post-assignment procedures that until now have been handled specifies post-assignment procedures that until now have been handled
in an ad hoc manner. These include procedures to de-register a port in an ad hoc manner. These include procedures to de-register a port
number that is no longer in use, to re-use a port number allocated number that is no longer in use, to re-use a port number allocated
for one application that is no longer in use for another application, for one application that is no longer in use for another application,
and the procedure by which IANA can unilaterally revoke a prior port and the procedure by which IANA can unilaterally revoke a prior port
number registration. Section 8 discusses the specifics of these number assignment. Section 8 discusses the specifics of these
procedures and processes that requesters and IANA follow for all procedures and processes that requesters and IANA follow for all
requests for all current and future transport protocols. requests for all current and future transport protocols.
It is important to note that ownership of registered port numbers and IANA is the authority for assigning service names and port numbers.
service names remains with IANA. For protocols developed by IETF The registries that are created to store these registrations are
working groups, IANA now also offers a method for the "early" maintained by IANA. For protocols developed by IETF working groups,
assignment of port numbers and service names [RFC4020], as described IANA now also offers a method for the "early assignment" [RFC4020] of
in Section 8.1. service names and port numbers, as described in Section 8.1.
This document updates IANA's procedures for UDP and TCP port numbers This document updates IANA's procedures for UDP and TCP port numbers
by obsoleting Sections 8 and 9.1 of the IANA allocation guidelines by obsoleting Sections 8 and 9.1 of the IANA allocation guidelines
[RFC2780]. (Note that different sections of the IANA allocation [RFC2780]. (Note that other sections of the IANA allocation
guidelines, relating to the protocol field values in IPv4 header, guidelines, relating to the protocol field values in IPv4 header,
were also updated in February 2008 [RFC5237].) This document also were also updated in February 2008 [RFC5237].) This document also
updates the IANA allocation procedures for DCCP [RFC4340] and SCTP updates the IANA allocation procedures for DCCP [RFC4340] and SCTP
[RFC4960]. [RFC4960].
The Lightweight User Datagram Protocol (UDP-Lite) [RFC5237] shares The Lightweight User Datagram Protocol (UDP-Lite) [RFC5237] shares
the port space with UDP. The UDP-Lite specification says: "UDP-Lite the port space with UDP. The UDP-Lite specification says: "UDP-Lite
uses the same set of port number values assigned by the IANA for use uses the same set of port number values assigned by the IANA for use
by UDP". Thus the update of UDP procedures result in an update also by UDP". Thus the update of UDP procedures result in an update also
of the UDP-Lite procedures. of the UDP-Lite procedures.
This document also clarify what a service name is and how it is This document also clarifies what a service name is and how it is
registered. This will impact the DNS SRV specification, because that registered. This will impact the DNS SRV specification [RFC2782],
specification merely makes a brief mention that the symbolic names of because that specification merely makes a brief mention that the
services are defined in "Assigned Numbers" [RFC1700], without stating symbolic names of services are defined in "Assigned Numbers"
to which section of that 230-page document it refers. The DNS SRV [RFC1700], without stating to which section it refers within that
specification may have been referring to the list of Port Assignments 230-page document. The DNS SRV specification may have been referring
(known as /etc/services on Unix), or to the "Protocol And Service to the list of Port Assignments (known as /etc/services on Unix), or
Names" section, or to both, or to some other section. Furthermore, to the "Protocol And Service Names" section, or to both, or to some
"Assigned Numbers" is now obsolete [RFC3232] and has now been other section. Furthermore, "Assigned Numbers" is now obsolete
replaced by on-line registries [PORTREG][PROTSERVREG]. There are [RFC3232] and has been replaced by on-line registries
additional updates and clarifications on how DNS SRV utilize the [PORTREG][PROTSERVREG].
Service name registry created in this document in "Clarification of
DNS SRV Owner Names" [I-D.gudmundsson-dnsext-srv-clarify].
The development of new transport protocols is a major effort that the The development of new transport protocols is a major effort that the
IETF does not undertake very often. If a new transport protocol is IETF does not undertake very often. If a new transport protocol is
standardized in the future, for the purpose of uniformity it is standardized in the future, for consistency it is expected to follow
expected to follow as much as possible the guidelines and practices as much as possible the guidelines and practices around using service
around using port numbers and service names. names and port numbers.
2. Motivation 2. Motivation
Information about the registration procedures for the port registry Information about the registration procedures for the port registry
has existed in three locations: the forms for requesting port number has existed in three locations: the forms for requesting port number
registrations on the IANA web site [SYSFORM] [USRFORM], an registrations on the IANA web site [SYSFORM] [USRFORM], an
introductory text section in the file listing the port number introductory text section in the file listing the port number
registrations themselves [PORTREG], and two brief sections of the registrations themselves [PORTREG], and two brief sections of the
IANA Allocation Guidelines [RFC2780]. IANA Allocation Guidelines [RFC2780].
Similarly, the procedures surrounding service names have been Similarly, the procedures surrounding service names have been
historically unclear. Service names were originally created as historically unclear. Service names were originally created as
mnemonic identifiers for port numbers without a well-defined syntax, mnemonic identifiers for port numbers without a well-defined syntax,
beyond the 14-character limit mentioned on the IANA website [SYSFORM] beyond the 14-character limit mentioned on the IANA website [SYSFORM]
[USRFORM]. Even that length limit has not been consistently applied, [USRFORM]. Even that length limit has not been consistently applied,
and some assigned service names are 15 characters long. When service and some assigned service names are 15 characters long. When service
identification via DNS SRV RRs was introduced, the requirement by identification via DNS SRV Resource Records (RRs) was introduced, the
IANA to only assign service names and port numbers in combination, requirement by IANA to only assign service names and port numbers in
led to the creation of an ad hoc service name registry outside of the combination, led to the creation of an ad hoc service name registry
control of IANA [SRVREG]. outside of the control of IANA [SRVREG].
This document aggregates all this scattered information into a single This document aggregates all this scattered information into a single
reference that aligns and clearly defines the management procedures reference that aligns and clearly defines the management procedures
for both port numbers and service names. It gives more detailed for both service names and port numbers. It gives more detailed
guidance to prospective requesters of ports and service names than guidance to prospective requesters of service names and ports than
the existing documentation, and it streamlines the IANA procedures the existing documentation, and it streamlines the IANA procedures
for the management of the registry, so that management requests can for the management of the registry, so that requests can be completed
complete in a timely manner. in a timely manner.
This document defines rules for registration of service names without This document defines rules for registration of service names without
associated port numbers, for such usages as DNS SRV records associated port numbers, for such usages as DNS SRV records
[RFC2782], which was not possible under the previous IANA procedures. [RFC2782], which was not possible under the previous IANA procedures.
The document also merges service name registrations from the non-IANA The document also merges service name registrations from the non-IANA
ad hoc registry [SRVREG] and from the IANA "Protocol and Service ad hoc registry [SRVREG] and from the IANA "Protocol and Service
Names" registry [PROTSERVREG] into the IANA "Port and Service Name" Names" registry [PROTSERVREG] into the IANA "Service Name and
registry [PORTREG], which from here on is the single authoritative Transport Protocol Port Number" registry [PORTREG], which from here
registry for service names and port numbers. on is the single authoritative registry for service names and port
numbers.
An additional purpose of this document is to describe the principles An additional purpose of this document is to describe the principles
that guide the IETF and IANA in their role as the long-term joint that guide the IETF and IANA in their role as the long-term joint
stewards of the port number registry. TCP and UDP have been a stewards of the service name and port number registry. TCP and UDP
remarkable success over the last decades. Thousands of applications have had remarkable success over the last decades. Thousands of
and application-level protocols have registered ports and service applications and application-level protocols have service names and
names for their use, and there is every reason to believe that this ports assigned for their use, and there is every reason to believe
trend will continue into the future. It is hence extremely important that this trend will continue into the future. It is hence extremely
that management of the registry follow principles that ensure its important that management of the registry follow principles that
long-term usefulness as a shared resource. Section 7 discusses these ensure its long-term usefulness as a shared resource. Section 7
principles in detail. discusses these principles in detail.
3. Background 3. Background
The Transmission Control Protocol (TCP) [RFC0793] and the User The Transmission Control Protocol (TCP) [RFC0793] and the User
Datagram Protocol (UDP) [RFC0768] have enjoyed a remarkable success Datagram Protocol (UDP) [RFC0768] have enjoyed a remarkable success
over the decades as the two most widely used transport protocols on over the decades as the two most widely used transport protocols on
the Internet. They have relied on the concept of "ports" as logical the Internet. They have relied on the concept of "ports" as logical
entities for Internet communication. Ports serve two purposes: entities for Internet communication. Ports serve two purposes:
first, they provide a demultiplexing identifier to differentiate first, they provide a demultiplexing identifier to differentiate
transport sessions between the same pair of endpoints, and second, transport sessions between the same pair of endpoints, and second,
they may also identify the application protocol and associated they may also identify the application protocol and associated
service to which processes bind. Newer transport protocols, such as service to which processes bind. Newer transport protocols, such as
the Stream Control Transmission Protocol (SCTP) [RFC4960] and the the Stream Control Transmission Protocol (SCTP) [RFC4960] and the
Datagram Congestion Control Protocol (DCCP) [RFC4342] have adopted Datagram Congestion Control Protocol (DCCP) [RFC4342] have also
the concept of ports for their communication sessions and use 16-bit adopted the concept of ports for their communication sessions and use
port numbers in the same way as TCP and UDP (and UDP-Lite [RFC3828], 16-bit port numbers in the same way as TCP and UDP (and UDP-Lite
a variant of UDP). [RFC3828], a variant of UDP).
Port numbers are the original and most widely used means for Port numbers are the original and most widely used means for
application and service identification on the Internet. Ports are application and service identification on the Internet. Ports are
16-bit numbers, and the combination of source and destination port 16-bit numbers, and the combination of source and destination port
numbers together with the IP addresses of the communicating end numbers together with the IP addresses of the communicating end
systems uniquely identifies a session of a given transport protocol. systems uniquely identifies a session of a given transport protocol.
Port numbers are also known by their associated service names such as
Port numbers are also known by their corresponding service names such "telnet" for port number 23 and "http" (as well as "www" and "www-
as "telnet" for port number 23 and "http" (and the "www" alias) for http") for port number 80.
port number 80.
Hosts running services, hosts accessing services on other hosts, and Hosts running services, hosts accessing services on other hosts, and
intermediate devices (such as firewalls and NATs) that restrict intermediate devices (such as firewalls and NATs) that restrict
services need to agree on which service corresponds to a particular services need to agree on which service corresponds to a particular
destination port. Although this is ultimately a local decision with destination port. Although this is ultimately a local decision with
meaning only between the endpoints of a connection, it is common for meaning only between the endpoints of a connection, it is common for
many services to have a default port upon which those servers usually many services to have a default port upon which those servers usually
listen, when possible, and these ports are recorded by the Internet listen, when possible, and these ports are recorded by the Internet
Assigned Numbers Authority (IANA) through the port number registry Assigned Numbers Authority (IANA) through the service name and port
[PORTREG]. number registry [PORTREG].
Over time, the assumption that a particular port number necessarily Over time, the assumption that a particular port number necessarily
implies a particular service may become less true. For example, implies a particular service may become less true. For example,
multiple instances of the same service on the same host cannot multiple instances of the same service on the same host cannot
generally listen on the same port, and multiple hosts behind the same generally listen on the same port, and multiple hosts behind the same
NAT gateway cannot all have a mapping for the same port on the NAT gateway cannot all have a mapping for the same port on the
external side of the NAT gateway, whether using static port mappings external side of the NAT gateway, whether using static port mappings
configured by hand by the user, or dynamic port mappings configured configured by hand by the user, or dynamic port mappings configured
automatically using a port mapping protocol NAT Port Mapping Protocol automatically using a port mapping protocol like NAT Port Mapping
(NAT-PMP) [I-D.cheshire-nat-pmp] or Internet Gateway Device (IGD) Protocol (NAT-PMP) [I-D.cheshire-nat-pmp] or Internet Gateway Device
[IGD]. (IGD) [IGD].
Applications either use numeric port numbers directly, look up port Applications may use numeric port numbers directly, look up port
numbers based on service names via system calls such as numbers based on service names via system calls such as
getservbyname() on UNIX, look up port numbers by performing queries getservbyname() on UNIX, look up port numbers by performing queries
for DNS SRV records [RFC2782][I-D.cheshire-dnsext-dns-sd] or for DNS SRV records [RFC2782][I-D.cheshire-dnsext-dns-sd], or
determine port numbers in a variety of other ways like the TCP Port determine port numbers in a variety of other ways like the TCP Port
Service Multiplexer (TCPMUX) [RFC1078]. Service Multiplexer (TCPMUX) [RFC1078].
Designers of applications and application-level protocols may apply Designers of applications and application-level protocols may apply
to IANA for an assigned port number and service name for a specific to IANA for an assigned service name and port number for a specific
application, and may - after successful registration - assume that no application, and may - after successful registration - assume that no
other application will use that port number or service name for its other application will use that service name or port number for its
communication sessions. Alternatively, application designers may communication sessions. Alternatively, application designers may
also ask for only an assigned service name, if their application does also ask for only an assigned service name, if their application does
not require a fixed port number. The latter alternative is not require a fixed port number. The latter alternative is
encouraged when possible, in order to conserve the more limited port encouraged when possible, in order to conserve the more limited port
number space. This includes, for example, applications that use DNS number space. This is applicable, for example, to applications that
SRV records to look up port numbers at runtime. use DNS SRV records to look up port numbers at runtime.
4. Conventions Used in this Document 4. Conventions Used in this Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in "Key words for use in
RFCs to Indicate Requirement Levels" [RFC2119].
5. Service Names 5. Service Names
Service names are the unique key in the Port and Service Name Service names are the unique key in the Service Name and Transport
registry. This unique symbolic name for a service may also be used Protocol Port Number Registry. This unique symbolic name for a
for other purposes, such as in DNS SRV records [RFC2782]. Within the service may also be used for other purposes, such as in DNS SRV
registry, this unique key ensures that different services can be records [RFC2782]. Within the registry, this unique key ensures that
unambiguously distinguished, thus preventing name collisions and different services can be unambiguously distinguished, thus
avoiding confusion about who is the administrative contact for a preventing name collisions and avoiding confusion about who is the
particular entry. Registrant for a particular entry.
For each service name, there may exist zero or more associated port
number assignments. A port number assignment associated with a
service name contains the transport protocol, port number and
possibly additional data, such as a DCCP Service Code.
There may be more than one service name associated with a particular There may be more than one service name associated with a particular
transport protocol and port. There are two valid reasons for transport protocol and port. There are three ways that such service
allowing service name aliases: name overloading can occur:
o Aliases are permissible when all such service names are for the
same service, such as with "http" and "www", which both name TCP
port 80. In such cases, one of the service names SHOULD be
designated primary, for use with mechanisms such as DNS SRV
Records [RFC2782], and the others SHOULD be designated as aliases
of the primary service name. This is necessary so that clients
and servers using a service discovery mechanism use a consistent
name by which to refer to a given service. Otherwise, if a server
were to advertise that it supports the "www" service, and a client
were to seek instances of the "http" service, that client would
fail to discover that server, defeating the purpose of having a
service discovery mechanism. For aliases that do not indicate a
primary alias, a server is expected to register itself under all
aliased service names.
o Aliases are also permissible when one service is an extension of o Overloading occurs when one service is an extension of another
another service, and an in-band mechanisms exists for determining service, and an in-band mechanism exists for determining if the
if the extension is present or not. One example is port 3478, extension is present or not. One example is port 3478, which has
which has the service name aliases "stun" and "turn". TURN the service name aliases "stun" and "turn". TURN [RFC5766] is an
[RFC5766] is an extension to the STUN [RFC5389] service. TURN- extension to the STUN [RFC5389] service. TURN-enabled clients
enabled clients wishing to locate TURN servers could attempt to wishing to locate TURN servers could attempt to discover "stun"
discover "stun" services and then checking in-band if the server services and then check in-band if the server supports TURN, but
supports TURN, but this is inefficient. Enabling them to directly this would be inefficient. Enabling them to directly query for
query for "turn" servers by name is a better approach. (Note that "turn" servers by name is a better approach. (Note that TURN
TURN servers in this case should also be locatable via a "stun" servers in this case should also be locatable via a "stun"
discovery, because every TURN server is also a STUN server.) discovery, because every TURN server is also a STUN server.)
o By historical accident the service name "http" corresponds to the
same port number as "www" and "www-http". When used in SRV
records [RFC2782], and similar service discovery mechanisms only
the service name "http" should be used, not these additional
names. If a server were to advertise "www" then it would not be
discovered by clients browsing for "http". Advertising or
browsing for the aliases as well as the primary service name would
be inefficient, and achieves nothing that it not already achieved
by using the service name "http" exclusively.
o As indicated in this document, in Section 10.1, to enable legacy
names to be replaced with names consistent with the syntax this
document prescribes. In this case, only the new name should be
used in SRV records, both to avoid the same issues as with
historical cases of multiple names, as well as because the legacy
names are incompatible with SRV record use.
For future assignments, applications will not be permitted that
merely request a new name exactly duplicating an existing service.
Having multiple names for the same service serves no purpose.
Implementers are requested to inform IANA if they discover other
cases where a single service has multiple names, so that one name may
be recorded as the primary name for service discovery purposes.
Service names are assigned on a "first come, first served" basis, as Service names are assigned on a "first come, first served" basis, as
described in Section 8.1. Names should be brief and informative, described in Section 8.1. Names should be brief and informative,
avoiding words or abbreviations that are redundant in the context of avoiding words or abbreviations that are redundant in the context of
the registry (e.g., "port", "service", "protocol", etc.) Names the registry (e.g., "port", "service", "protocol", etc.) Names
referring to discovery services, e.g., using multicast or broadcast referring to discovery services, e.g., using multicast or broadcast
to identify endpoints capable of a given service, SHOULD use an to identify endpoints capable of a given service, SHOULD use an
easily identifiable suffix (e.g., "-disc"). easily identifiable suffix (e.g., "-disc").
5.1. Service Name Syntax 5.1. Service Name Syntax
Valid service names MUST contain only these US-ASCII [ANSI.X3-4.1986] Valid service names are hereby normatively defined as follows:
characters: letters from A to Z and a to z, digits from 0 to 9, and
hyphens ("-", ASCII 0x2D or decimal 45). They MUST be at least one
character and no more than fifteen characters long, MUST NOT begin or
end with a hyphen, and MUST NOT consist of only digits (in order to
be distinguishable from port numbers, which are typically written as
all digits).
The service name syntax MAY be used to validate a service name o MUST be at least 1 character and no more than 15 characters long
string, but MUST NOT be used for any other purpose (e.g.,
delineation). Any system that includes a service name inside a
longer string is itself responsible for delineating the service name.
Such systems MUST NOT rely on the syntax of a service name alone for
such delineation.
The syntax defined in ABNF [RFC5234]: o MUST contain only US-ASCII [ANSI.X3-4.1986] letters 'A' - 'Z' and
'a' - 'z', digits '0' - '9', and hyphens ('-', ASCII 0x2D or
decimal 45)
SRVNAME = (ALPHA / *([HYPHEN] ALNUM)) / o MUST contain at least one letter ('A' - 'Z' or 'a' - 'z')
(1*DIGIT ((HYPHEN ALNUM) / ALPHA) *([HYPHEN] ALNUM))
ALNUM = ALPHA / DIGIT ; A-Z, a-z, 0-9 o MUST NOT begin or end with a hyphen
HYPHEN = %x2d ; "-"
ALPHA = <See [RFC5234]> o hyphens MUST NOT be adjacent to other hyphens
DIGIT = <See [RFC5234]>
The reason for requiring at least one letter is to avoid service
names like "23" (could be confused with a numeric port number) or
"6000-6063" (could be confused with a numeric port number range).
Although service names may contain both upper-case and lower-case
letters, case is ignored for comparison purposes, so both "http" and
"HTTP" denote the same service.
Service names are purely opaque identifiers, and no semantics are
implied by any superficial structure that a given service name may
appear to have. For example, a company called "Example" may choose
to register service names "Example-Foo" and "Example-Bar" for its
"Foo" and "Bar" products, but the "Example" company can't claim to
"own" all service names beginning with "Example-", they can't prevent
someone else registering "Example-Baz" for a different service, and
they can't prevent other developers from using the "Example-Foo" and
"Example-Bar" service types in order to interoperate with the "Foo"
and "Bar" products. Technically speaking, in service discovery
protocols, service names are merely a series of byte values on the
wire; for the mnemonic convenience of human developers it can be
convenient to interpret those byte values as human-readable ascii
characters, but software should treat them as purely opaque
identifiers and not attempt to parse them for any additional embedded
meaning.
In approximately 98% of cases, the new "service name" is exactly the
same as the old historic "short name" from the IANA web forms
[SYSFORM] [USRFORM]. In approximately 2% of cases, the new "service
name" is derived from the old historic "short name" as described
below in Section 10.1.
The rules for valid service names, excepting the limit of 15
characters maximum, are also expressed below (as a non-normative
convenience) using ABNF [RFC5234].
SRVNAME = (ALPHA / (1*DIGIT [HYPHEN] ALPHA)) *([HYPHEN] ALNUM)
ALNUM = ALPHA / DIGIT ; A-Z, a-z, 0-9
HYPHEN = %x2d ; "-"
ALPHA = %x41-5A / %x61-7A ; A-Z / a-z [RFC5234]
DIGIT = %x30-39 ; 0-9 [RFC5234]
5.2. Service Name Usage in DNS SRV Records 5.2. Service Name Usage in DNS SRV Records
The DNS SRV specification [RFC2782] requests that the Service Label The DNS SRV specification [RFC2782] states that the Service Label
part of the owner name of DNS SRV records includes a "Service" part of the owner name of a DNS SRV record includes a "Service"
element, defined to be "the symbolic name of the desired service", element, described as "the symbolic name of the desired service", but
but did not state precisely which part of the IANA database (i.e. as discussed above, it is not clear precisely what this means.
STD 2 when [RFC2782] was written) serves as a registry for standard
service names.
This document clarifies that the Service Label MUST be a service name This document clarifies that the Service Label MUST be a service name
as defined herein. The service name SHOULD be registered with IANA as defined herein. The service name SHOULD be registered with IANA
and recorded in the Service Names and Port Numbers registry and recorded in the Service Name and Transport Protocol Port Number
[PORTREG]. This is needed to ensure that only a single registry of Registry [PORTREG].
Service Names exists and name collisions can be avoided in the
future.
The details of the use of Service Names from [PORTREG] in SRV Service
Labels are specified in [RFC2782] and the documents updating or
replacing that specification (see the companion document
[I-D.gudmundsson-dnsext-srv-clarify] for more information).
The details of how applications make use of DNS SRV should be The details of using Service Names in SRV Service Labels are
specified in the documentation set of the application/service. In specified in the DNS SRV specification [RFC2782]. This document does
the absence of such specification, prospective clients of a given not change that specification.
service should not assume the existence of SRV RRs for this service
or, if they have indications that this will be the case (e.g., by
configuration), must assume the unextended naming scheme from
[RFC2782] for service discovery with DNS SRV, i.e., the Service Label
is constructed from the Service Name registered in [PORTREG] by
prepending a single underscore character ("_").
6. Port Number Ranges 6. Port Number Ranges
TCP, UDP, UDP-Lite, SCTP and DCCP use 16-bit namespaces for their TCP, UDP, UDP-Lite, SCTP and DCCP use 16-bit namespaces for their
port number registries. The port registries for all these transport port number registries. The port registries for all these transport
protocols are subdivided into three ranges of numbers, and protocols are subdivided into three ranges of numbers, and
Section 7.3 describes the IANA procedures for each range in detail: Section 8.1.1 describes the IANA procedures for each range in detail:
o the Well Known Ports, also known as the System Ports, from 0-1023 o the System Ports, also known as the Well Known Ports, from 0-1023
(assigned by IANA) (assigned by IANA)
o the Registered Ports, also known as the User Ports, from 1024- o the User Ports, also known as the Registered Ports, from 1024-
49151 (assigned by IANA) 49151 (assigned by IANA)
o the Dynamic Ports, also known as the Private Ports, from 49152- o the Dynamic Ports, also known as the Private Ports, from 49152-
65535 (never assigned) 65535 (never assigned)
Of the assignable port ranges (Well Known and Registered, i.e., port Of the assignable port ranges (System Ports and User Ports, i.e.,
numbers 0-49151), individual port numbers are in one of three states port numbers 0-49151), individual port numbers are in one of three
at any given time: states at any given time:
o Assigned: Assigned port numbers are currently allocated to the o Assigned: Assigned port numbers are currently allocated to the
service indicated in the registry. service indicated in the registry.
o Unassigned: Unassigned port numbers are currently available for o Unassigned: Unassigned port numbers are currently available for
assignment upon request, as per the procedures outlined in this assignment upon request, as per the procedures outlined in this
document. document.
o Reserved: Reserved port numbers are not available for regular o Reserved: Reserved port numbers are not available for regular
assignment; they are "assigned to IANA" for special purposes. assignment; they are "assigned to IANA" for special purposes.
skipping to change at page 11, line 4 skipping to change at page 11, line 21
o Assigned: Assigned port numbers are currently allocated to the o Assigned: Assigned port numbers are currently allocated to the
service indicated in the registry. service indicated in the registry.
o Unassigned: Unassigned port numbers are currently available for o Unassigned: Unassigned port numbers are currently available for
assignment upon request, as per the procedures outlined in this assignment upon request, as per the procedures outlined in this
document. document.
o Reserved: Reserved port numbers are not available for regular o Reserved: Reserved port numbers are not available for regular
assignment; they are "assigned to IANA" for special purposes. assignment; they are "assigned to IANA" for special purposes.
Reserved port numbers include values at the edges of each range, Reserved port numbers include values at the edges of each range,
e.g., 0, 1023, 1024, etc., which may be used to extend these e.g., 0, 1023, 1024, etc., which may be used to extend these
ranges or the overall port number space in the future. ranges or the overall port number space in the future.
In order to keep the size of the registry manageable, IANA typically In order to keep the size of the registry manageable, IANA typically
only records the Assigned and Reserved port numbers and service names only records the Assigned and Reserved service names and port numbers
in the registry. Unassigned values are typically not explicitly in the registry. Unassigned values are typically not explicitly
listed. listed. (There are an near-infinite number of Unassigned service
names and enumerating them all would not be practical.)
As a data point, when this document was written, approximately 76% of As a data point, when this document was written, approximately 76% of
the TCP and UDP Well Known Ports were assigned, and approximately 9% the TCP and UDP System Ports were assigned, and approximately 9% of
of the Registered Ports were assigned. (As noted, Dynamic Ports are the User Ports were assigned. (As noted, Dynamic Ports are never
never assigned.) assigned.)
6.1. Port Numbers and Service Names for Experimentation 6.1. Service names and Port Numbers for Experimentation
Of the Well Known ports, two TCP and UDP port numbers (1021 and Of the System Ports, two TCP and UDP port numbers (1021 and 1022),
1022), together with their respective service names ("exp1" and together with their respective service names ("exp1" and "exp2"),
"exp2"), have been assigned for experimentation with new applications have been assigned for experimentation with new applications and
and application-layer protocols that require a port number in the application-layer protocols that require a port number in the
assigned ports ranges [RFC4727]. assigned ports ranges [RFC4727].
Please refer to Sections 1 and 1.1 of "Assigning Experimental and Please refer to Sections 1 and 1.1 of "Assigning Experimental and
Testing Numbers Considered Useful" [RFC3692] for how these Testing Numbers Considered Useful" [RFC3692] for how these
experimental port numbers are to be used. experimental port numbers are to be used.
This document registers the same two port numbers and service names This document registers the same two service names and port numbers
for experimentation with new application-layer protocols over SCTP for experimentation with new application-layer protocols over SCTP
and DCCP in Section 10.2. and DCCP in Section 10.2.
Unfortunately, it can be difficult to limit access to these ports. Unfortunately, it can be difficult to limit access to these ports.
Users SHOULD take measures to ensure that experimental ports are Users SHOULD take measures to ensure that experimental ports are
connecting to the intended process. For example, users of these connecting to the intended process. For example, users of these
experimental ports might include a 64-bit nonce, once on each segment experimental ports might include a 64-bit nonce, once on each segment
of a message-oriented channel (e.g., UDP), or once at the beginning of a message-oriented channel (e.g., UDP), or once at the beginning
of a byte-stream (e.g., TCP), which is used to confirm that the port of a byte-stream (e.g., TCP), which is used to confirm that the port
is being used as intended. Such confirmation of intended use is is being used as intended. Such confirmation of intended use is
especially important when these ports are associated with privileged especially important when these ports are associated with privileged
(e.g., system or administrator) processes. (e.g., system or administrator) processes.
7. Principles for Port Number and Service Name Registry Management 7. Principles for Service Name and Transport Protocol Port Number
Registry Management
Management procedures for the port number and service name registry Management procedures for the service name and transport protocol
include allocation of port numbers and service names upon request, as port number registry include allocation of service names and port
well as coordination of information about existing allocations. The numbers upon request, as well as management of information about
latter includes maintaining contact and description information about existing allocations. The latter includes maintaining contact and
assignments, revoking abandoned assignments, and redefining description information about assignments, revoking abandoned
assignments when needed. Of these procedures, port number allocation assignments, and redefining assignments when needed. Of these
is most critical, in order to continue to conserve the remaining port procedures, careful port number allocation is most critical, in order
numbers. to continue to conserve the remaining port numbers.
As noted earlier, only ~9% of the Registered Port space is currently As noted earlier, only about 9% of the User Port space is currently
assigned. The current rate of assignment is approximately 400 ports/ assigned. The current rate of assignment is approximately 400 ports
year, and has remained linear for the past 8 years. At that rate, if per year, and has remained steady for the past 8 years. At that
similar conservation continues, this resource will sustain another 85 rate, if similar conservation continues, this resource will sustain
years of assignment - without the need to resort to reassignment of another 85 years of assignment - without the need to resort to
released values or revocation. Note that the namespace available for reassignment of released values or revocation. The namespace
service names is even larger, which allows for a simpler management available for service names is much larger, which allows for simpler
procedures. management procedures.
7.1. Past Principles 7.1. Past Principles
Before the publication of this document, the principles of port Before the publication of this document, the principles of service
number and service name management followed a few mostly-undocumented name and port number management followed a few mostly-undocumented
guidelines. They are recorded here for historical purposes, and this guidelines. They are recorded here for historical purposes, and this
document updates them in Section 7.2. These principles were: document updates them in Section 7.2. These principles were:
o TCP and UDP ports were simultaneously allocated when either was o TCP and UDP ports were simultaneously allocated when either was
requested requested
o Port numbers were the primary allocation; service names were o Port numbers were the primary allocation; service names were
informative only, and did not have a well-defined syntax informative only, and did not have a well-defined syntax
o Port numbers were conserved informally, and sometimes o Port numbers were conserved informally, and sometimes
inconsistently (e.g., some services were allocated ranges of many inconsistently (e.g., some services were allocated ranges of many
port numbers even where not strictly necessary) port numbers even where not strictly necessary)
o SCTP and DCCP port number and service name registries were managed o SCTP and DCCP service name and port number registries were managed
separately from the TCP/UDP registries separately from the TCP/UDP registries
o Service names could not be assigned in the ports registry without o Service names could not be assigned in the old ports registry
assigning a corresponding port number at the same time without assigning an associated port number at the same time
This document clarifies and aligns these guidelines in order to more This document clarifies and aligns these guidelines in order to more
conservatively manage the limited remaining port number space and to conservatively manage the limited remaining port number space and to
enable and promote the use of service names for service enable and promote the use of service names for service
identification without associated port numbers, where possible. identification without associated port numbers, where possible.
7.2. Updated Principles 7.2. Updated Principles
This section summarizes the basic principles by which IANA handles This section summarizes the basic principles by which IANA handles
the Port and Service Name registry, and attempts to conserve the port the Service Name and Transport Protocol Port Number Registry, and
number space. This description is intended to inform applicants attempts to conserve the port number space. This description is
requesting service names and port numbers. IANA decisions are not intended to inform applicants requesting service names and port
required to be bound to these principles, however; other factors may numbers. IANA are not required to be bound by these principles when
come into play, and exceptions may occur where deemed in the best handling requests; other factors may come into play, and exceptions
interest of the Internet. may occur where deemed in the best interest of the Internet.
IANA will begin assigning service names that do not request a IANA will begin assigning service names that do not request an
corresponding port number allocation under a simple "First Come, associated port number allocation under a simple "First Come, First
First Served" policy [RFC5226]. IANA MAY, at its discretion, refer Served" policy [RFC5226]. IANA MAY, at its discretion, refer service
service name requests to "Expert Review" in cases of mass name requests to "Expert Review" in cases of mass registrations or
registrations or other situations where IANA believes expert review other situations where IANA believes expert review is advisable.
is advisable.
The basic principle of port number registry management is to conserve The basic principle of service name and port number registry
use of the port space where possible. Extensions to support larger management is to conserve use of the port space where possible.
port number spaces would require changing many core protocols of the Extensions to support larger port number spaces would require
current Internet in a way that would not be backward compatible and changing many core protocols of the current Internet in a way that
interfere with both current and legacy applications. To help ensure would not be backward compatible and interfere with both current and
this conservation the policy for any registration request for port legacy applications. To help ensure this conservation the policy for
number allocations uses the "Expert Review" policy [RFC5226]. any registration request for port number allocations uses the "Expert
Review" policy [RFC5226].
Conservation of the port number space is required because this space Conservation of the port number space is required because this space
is a limited resource, applications are expected to participate in is a limited resource, so applications are expected to participate in
the traffic demultiplexing process where feasible. The port numbers the traffic demultiplexing process where feasible. The port numbers
are expected to encode as little information as possible that will are expected to encode as little information as possible that will
still enable an application to perform further demultiplexing by still enable an application to perform further demultiplexing by
itself. In particular: itself. In particular:
o IANA will allocate only one assigned port number per service or o IANA will allocate only one assigned port number per service or
application application
o IANA will allocate only one assigned port number for all versions o IANA will allocate only one assigned port number for all versions
of a service (e.g., running the service with or without a security of a service (e.g., running the service with or without a security
mechanism, or for updated variants of a service) mechanism, or for updated variants of a service)
o IANA will allocate only one assigned port number for all different o IANA will allocate only one assigned port number for all different
types of device using or participating in the same service types of device using or participating in the same service
o IANA will allocate port numbers only for the transport protocol(s) o IANA will allocate port numbers only for the transport protocol(s)
explicitly named in an registration request explicitly named in a registration request
o IANA may recover unused port numbers, via the new procedures of o IANA may recover unused port numbers, via the new procedures of
de-registration, revocation, and transfer de-registration, revocation, and transfer
A given service is expected to further demultiplex messages where Where possible, a given service is expected to demultiplex messages
possible. For example, applications and protocols are expected to if necessary. For example, applications and protocols are expected
include in-band version information, so that future versions of the to include in-band version information, so that future versions of
application or protocol can share the same allocated port. the application or protocol can share the same allocated port.
Applications and protocols are also expected to be able to Applications and protocols are also expected to be able to
efficiently use a single allocated port for multiple sessions, either efficiently use a single allocated port for multiple sessions, either
by demultiplexing multiple streams within one port, or using the by demultiplexing multiple streams within one port, or using the
allocated port to coordinate using dynamic ports for subsequent allocated port to coordinate using dynamic ports for subsequent
exchanges (e.g., in the spirit of FTP [RFC0959]). exchanges (e.g., in the spirit of FTP [RFC0959]).
Ports are used in various ways, notably: Ports are used in various ways, notably:
o as endpoint process identifiers o as endpoint process identifiers
o as application protocol identifiers o as application protocol identifiers
o for firewall filtering purposes o for firewall filtering purposes
The process and protocol identifier use suggests that anything a Both the process identifier and the protocol identifier uses suggest
single process can demultiplex, or that can be encoded into a single that anything a single process can demultiplex, or that can be
protocol, should be. The firewall filtering use suggests that some encoded into a single protocol, should be. The firewall filtering
uses that could be multiplexed or encoded must be separated to allow use suggests that some uses that could be multiplexed or encoded
for firewall management. Note that this latter use is much less could instead be separated to allow for easier firewall management.
sound, because port numbers have meaning only for the two endpoints Note that this latter use is much less sound, because port numbers
involved in a connection, and drawing conclusions about the service have meaning only for the two endpoints involved in a connection, and
that generated a given flow based on observed port numbers is not drawing conclusions about the service that generated a given flow
always reliable. Further, previous separation of protocol variants based on observed port numbers is not always reliable. Further,
based on security capabilities (e.g., HTTP on TCP port 80 vs. HTTPS previous separation of protocol variants based on security
on TCP port 443) is not recommended for new protocols, because all capabilities (e.g., HTTP on TCP port 80 vs. HTTPS on TCP port 443) is
should be security-capable and capable of negotiating the use of not recommended for new protocols, because all new protocols should
security in-band. be security-capable and capable of negotiating the use of security
in-band.
IANA will begin assigning port numbers for only those transport IANA will begin assigning port numbers for only those transport
protocols explicitly included in a registration request. This ends protocols explicitly included in a registration request. This ends
the long-standing practice of automatically assigning a port number the long-standing practice of automatically assigning a port number
to an application for both TCP and a UDP, even if the request is for to an application for both TCP and a UDP, even if the request is for
only one of these transport protocols. The new allocation procedure only one of these transport protocols. The new allocation procedure
conserves resources by allocating a port number to an application for conserves resources by allocating a port number to an application for
only those transport protocols (TCP, UDP, SCTP and/or DCCP) it only those transport protocols (TCP, UDP, SCTP and/or DCCP) it
actually uses. The port number will be marked as Reserved - instead actually uses. The port number will be marked as Reserved - instead
of Assigned - in the port number registries of the other transport of Assigned - in the port number registries of the other transport
protocols. When applications start supporting the use of some of protocols. When applications start supporting the use of some of
those additional transport protocols, the administrative contact for those additional transport protocols, the Registrant for the
the registration MUST request IANA to convert the reservation into a registration MUST request IANA to convert the reservation into a
proper assignment. An application MUST NOT assume that it can use a proper assignment. An application MUST NOT assume that it can use a
port number assigned to it for use with one transport protocol with port number assigned to it for use with one transport protocol with
another transport protocol without asking IANA to convert the another transport protocol without asking IANA to convert the
reservation into an assignment. reservation into an assignment.
When the available pool of unassigned numbers has run out in a ports When the available pool of unassigned numbers has run out in a ports
range, it will be necessary for IANA to consider the Reserved ports range, it will be necessary for IANA to consider the Reserved ports
for assignment. This is part of the motivation to not automatically for assignment. This is part of the motivation for not automatically
assigning ports for other transport protocols than the requested assigning ports for transport protocols other than the requested
ones. This will allow more ports to be available for assignment at one(s). This will allow more ports to be available for assignment
that point. It also shows the importance to register the transport when that time comes. To help conserve ports, application developers
protocols that are in fact used. should register only the transport protocols that their application
currently uses.
Conservation of port numbers is improved by procedures that allow Conservation of port numbers is improved by procedures that allow
previously allocated port numbers to become Unassigned, either previously allocated port numbers to become Unassigned, either
through de-registration or through revocation, and by a procedure through de-registration or through revocation, and by a procedure
that lets application designers transfer an allocated but unused port that lets application designers transfer an allocated but unused port
number to a new application. Section 8 describes these procedures, number to a new application. Section 8 describes these procedures,
which so far were undocumented. Port number conservation is also which until now were undocumented. Port number conservation is also
improved by recommending that applications that do not require an improved by recommending that applications that do not require an
allocated port chose this option and register only a service name. allocated port should register only a service name without an
associated port number.
7.3. Variances for Specific Port Number Ranges
Section 6 describes the different port number ranges. It is
important to note that IANA applies slightly different procedures
when managing the different ranges of the port number registry:
o Ports in the Dynamic Ports range (49152-65535) have been
specifically set aside for local and dynamic use and cannot be
registered through IANA. Applications may simply use them for
communication without any sort of registration. On the other
hand, applications MUST NOT assume that a specific port number in
the Dynamic Ports range will always be available for communication
at all times, and a port number in that range hence MUST NOT be
used as a service identifier.
o Ports in the Registered Ports range (1024-49151) are available for
registration through IANA, and MAY be used as service identifiers
upon successful registration. Because registering a port number
for a specific application consumes a fraction of the shared
resource that is the port number registry, IANA will require the
requester to document the intended use of the port number. This
documentation will be input to the "Expert Review" allocation
procedure [RFC5226], by which IANA will have a technical expert
review the request to determine whether to grant the registration.
The submitted documentation MUST explain why using a port number
in the Dynamic Ports range is unsuitable for the given
application. Ports in the Registered Ports range may also be
assigned under the "IETF Review" or "IESG Approval" allocation
procedures [RFC5226], which is how most assignments for IETF
protocols are handled.
o Ports in the Well Known Ports range (0-1023) are also available
for registration through IANA. Because the Well Known Ports range
is both the smallest and the most densely allocated, the
requirements for new allocations are more strict than those for
the Registered Ports range, and will only be granted under the
"IETF Review" or "IESG Approval" allocation procedures [RFC5226].
A request for a Well Known port number MUST document why using a
port number from both the Registered Ports and Dynamic Ports
ranges is unsuitable for the given application.
8. IANA Procedures for Managing the Port Number and Service Name 8. IANA Procedures for Managing the Service Name and Transport Protocol
Registry Port Number Registry
This section describes the process for requests associated with This section describes the process for handling requests associated
IANA's management of the port number and service name registry. Such with IANA's management of the Service Name and Transport Protocol
requests include initial registration, de-registration, re-use, Port Number Registry. Such requests include initial registration,
changes to the service name, as well as updates to the contact de-registration, re-use, changes to the service name, and updates to
information or description associated with an assignment. Revocation the contact information or description associated with an assignment.
is initiated by IANA. Revocation is as additional process, initiated by IANA.
8.1. Port Number and Service Name Registration 8.1. Service Name and Port Number Registration
Registration refers to the allocation of port numbers or service Registration refers to the allocation of service names or port
names to applicants. All such registrations are made from port numbers to applicants. All such registrations are made from service
numbers or service names that are Unassigned or Reserved at the time names or port numbers that are Unassigned or Reserved at the time of
of the allocation. Unassigned numbers and names are allocated as the allocation. Unassigned names and numbers are allocated according
needed, and without further explanation. Reserved numbers and names to the rules described in Section 8.1.1 below. Reserved numbers and
are assigned only after review by IANA and the IETF, and are names are assigned only by Standards Action or IESG Approval, and
accompanied by a statement explaining the reason a Reserved number or MUST accompanied by a statement explaining the reason a Reserved
name is appropriate for this action. number or name is appropriate for this action.
When a registration for one or more transport protocols is approved, When a registration for one or more transport protocols is approved,
the port number for any non-requested transport protocol(s) will be the port number for any non-requested transport protocol(s) will be
marked as Reserved. IANA SHOULD NOT assign that port number to any marked as Reserved. IANA SHOULD NOT assign that port number to any
other application or service until no other port numbers remain other application or service until no other port numbers remain
Unassigned in the requested range. The current administrative Unassigned in the requested range. The current Registrant for a port
contact for a port number MAY register these Reserved port numbers number MAY register these Reserved port numbers for other transport
for other transport protocols when needed. protocols when needed.
Service names, on the other hand, are not tied to a specific
transport protocol, and registration requests for only a service name
(but not a port number) allocate that service name for use with all
transport protocols.
A port number or service name registration request contains some or A service name or port number registration request contains the
all of the following information. The combination of service name following information. The service name is the unique identifier of
and transport protocol is the unique identifier of a given service: a given service:
Service Name (REQUIRED) Service Name (REQUIRED)
Transport Protocol(s) (REQUIRED) Transport Protocol(s) (REQUIRED)
Registration Administrative Contact (REQUIRED) Registrant (REQUIRED)
Registration Technical Contact (REQUIRED) Contact (REQUIRED)
Port Number (OPTIONAL)
Service Code (only REQUIRED for DCCP)
Description (REQUIRED) Description (REQUIRED)
Reference (REQUIRED) Reference (REQUIRED)
Port Number (OPTIONAL)
Service Code (REQUIRED for DCCP only)
Known Unauthorized Uses (OPTIONAL) Known Unauthorized Uses (OPTIONAL)
Assignment Notes (OPTIONAL) Assignment Notes (OPTIONAL)
o Service Name: A desired unique service name for the service o Service Name: A desired unique service name for the service
associated with the registration request MUST be provided, for use associated with the registration request MUST be provided, for use
in various service selection and discovery mechanisms (including, in various service selection and discovery mechanisms (including,
but not limited to, DNS SRV records [RFC2782]). The name MUST be but not limited to, DNS SRV records [RFC2782]). The name MUST be
compliant with the syntax defined in Section 5.1. In order to be compliant with the syntax defined in Section 5.1. In order to be
unique, they MUST NOT be identical to any currently registered unique, they MUST NOT be identical to any currently assigned
service names in the IANA registry [PORTREG]. Service names are service name in the IANA registry [PORTREG]. Service names are
case-insensitive; they may be provided and entered into the case-insensitive; they may be provided and entered into the
registry with mixed case (e.g., for clarity), but for the purposes registry with mixed case for clarity, but for the comparison
of comparison, the case is ignored. purposes the case is ignored.
o Transport Protocol(s): The transport protocol(s) for which the o Transport Protocol(s): The transport protocol(s) for which a
allocation is requested MUST be provided. This field is currently allocation is requested MUST be provided. This field is currently
limited to one or more of TCP, UDP, SCTP, and DCCP. This field is limited to one or more of TCP, UDP, SCTP, and DCCP. Requests
required even for services with no port number. without any port allocation and only a service name are still
required to indicate which protocol the service uses.
o Registration Administrative Contact: Name and email address of the
administrative contact for the registration. This is REQUIRED.
The name of the administrative contact identifies the
organization, company, or individual who is responsible for the
registration. For registrations done through IETF-published RFCs,
the administrative contact will be the IESG.
o Registration Technical Contact: Name and email address of the
technical contact person for the registration. This is REQUIRED.
For individuals, this is the same as the Registration
Administrative Contact; for organizations, this is a point of
contact at that organization. Additional address information MAY
be provided. For registrations done through IETF-published RFCs,
the technical contact will be the IESG.
o Port Number: If assignment of a port number is desired, either the o Registrant: Name and email address of the Registrant. This is
currently Unassigned port number the requester suggests for REQUIRED. The Registrant is the Organization or Company
allocation, or the text "ANY", MUST be provided. If only a responsible for the initial registration. For registrations done
service name is to be assigned, this field MUST be empty. If a through IETF-published RFCs, the Registrant will be the IESG.
specific port number is requested, IANA is encouraged to allocate
the requested number. If the text "ANY" is specified, IANA will
choose a suitable number from the Registered Ports range. Note
that the applicant MUST NOT use the requested port prior to the
completion of the registration.
o Service Code: The request MUST include a desired unique DCCP o Contact: Name and email address of the Contact person for the
service code [RFC5595], if the registration request includes DCCP registration. This is REQUIRED. The Contact person is the
as a transport protocol, and MUST NOT include a requested DCCP responsible person for the Internet community to send questions
service code otherwise. Section 19.8 of [RFC4340] defines to. This person would also be authorized to submit changes on
requirements and rules for allocation, updated by this document. behalf of the Registrant; in cases of conflict between the
Registrant and the Contact, the Registrant decisions take
precedence. Additional address information MAY be provided. For
registrations done through IETF-published RFCs, the Contact will
be the IESG.
o Description: A short description of the service associated with o Description: A short description of the service associated with
the registration request is REQUIRED. It should avoid all but the the registration request is REQUIRED. It should avoid all but the
most well known acronyms. most well-known acronyms.
o Reference: A description of (or a reference to a document o Reference: A description of (or a reference to a document
describing) the protocol or application using this port. The describing) the protocol or application using this port. The
description must include whether the protocol uses either description must state whether the protocol uses broadcast,
broadcast, multicast, or anycast communication. multicast, or anycast communication.
For registrations requesting only a Service Name or a Service Name For registrations requesting only a Service Name, or a Service
and Registered Port, a statement that the protocol is proprietary Name and User Port, a statement that the protocol is proprietary
and not publicly documented is also acceptable provided that the and not publicly documented is also acceptable provided that the
above information regarding use of broadcast, multicast, or required information regarding use of broadcast, multicast, or
anycast is given. anycast is given.
For registration requests for a Registered Port, the registration For registration requests for a User Port, the registration
request MUST explain why a port number in the Dynamic Ports range request MUST explain why a port number in the Dynamic Ports range
is unsuitable for the given application. is unsuitable for the given application.
For registration requests for a Well Known Port, the registration For registration requests for a System Port, the registration
request MUST explain why a port number in the Registered Ports or request MUST explain why a port number in the User Ports or
Dynamic Ports ranges is unsuitable, and a reference to a stable Dynamic Ports ranges is unsuitable, and a reference to a stable
protocol specification document MUST be provided. For requests protocol specification document MUST be provided. For requests
from IETF Working Groups, IANA MAY accept "Early" registration from IETF Working Groups, IANA MAY accept "early registration"
requests referencing a sufficiently stable Internet Draft instead [RFC4020] requests referencing a sufficiently stable Internet
of a published Standards-Track RFC [RFC4020]. Draft instead of a published Standards-Track RFC.
o Port Number: If assignment of a port number is desired, either the
currently Unassigned or Reserved port number the requester
suggests for allocation, or indication of which port range, user
or system, that the requester requires, MUST be provided. If only
a service name is to be assigned, this field is left empty. If a
specific port number is requested, IANA is encouraged to allocate
the requested number. If a range is specified, IANA will choose a
suitable number from the User or System Ports ranges. Note that
the applicant MUST NOT use the requested port prior to the
completion of the registration.
o Service Code: If the registration request includes DCCP as a
transport protocol then the request MUST include a desired unique
DCCP service code [RFC5595], and MUST NOT include a requested DCCP
service code otherwise. Section 19.8 of the DCCP specification
[RFC4340] defines requirements and rules for allocation, updated
by this document.
o Known Unauthorized Uses: A list of uses by applications or o Known Unauthorized Uses: A list of uses by applications or
organizations who are not the assignee. This list may be organizations who are not the Registrant. This list may be
augmented by IANA after assignment when unauthorized uses are augmented by IANA after assignment when unauthorized uses are
reported. reported.
o Assignment Notes: Indications of owner/name change, or any other o Assignment Notes: Indications of owner/name change, or any other
assignment process issue. This list may be updated by IANA after assignment process issue. This list may be updated by IANA after
assignment to help track changes to an assignment, e.g., de- assignment to help track changes to an assignment, e.g., de-
registration, owner/name changes, etc. registration, owner/name changes, etc.
If the registration request is for the addition of a new transport If the registration request is for the addition of a new transport
protocol to an already assigned service name, IANA needs to confirm protocol to an already assigned service name, IANA needs to confirm
with the administrative contact for the existing assignment whether with the Registrant for the existing assignment whether this addition
this addition is appropriate. is appropriate.
If the registration request is for a service name alias (see If the registration request is for a service name overloading a port
Section 5), IANA needs to confirm with the administrative contact for number (see Section 5), IANA needs to confirm with the Registrant for
the existing service name whether the registration of the alias is the existing service name whether the registration of the overloading
appropriate. is appropriate.
When IANA receives a registration request - containing the above When IANA receives a registration request - containing the above
information - that is requesting a port number, IANA SHALL initiate information - that is requesting a port number, IANA SHALL initiate
an "Expert Review" [RFC5226] in order to determine whether an an "Expert Review" [RFC5226] in order to determine whether an
assignment should be made. For requests that do not include a port assignment should be made. For requests that are not requesting a
number, IANA SHOULD assign the service name under a simple "First port number, IANA SHOULD assign the service name under a simple
Come First Served" policy [RFC5226]. "First Come First Served" policy [RFC5226].
8.2. Port Number and Service Name De-Registration 8.1.1. Variances for Specific Port Number Ranges
The administrative contact of a granted port number assignment can Section 6 describes the different port number ranges. It is
return the port number to IANA at any time if they no longer have a important to note that IANA applies slightly different procedures
need for it. The port number will be de-registered and will be when managing the different port ranges of the service name and port
marked as Reserved. IANA should not re-assign port numbers that have number registry:
been de-registered until all other available port numbers in the
specific range have been assigned. o Ports in the Dynamic Ports range (49152-65535) have been
specifically set aside for local and dynamic use and cannot be
assigned through IANA. Application software may simply use them
for communication without any sort of registration. On the other
hand, application software MUST NOT assume that a specific port
number in the Dynamic Ports range will always be available for
communication at all times, and a port number in that range hence
MUST NOT be used as a service identifier.
o Ports in the User Ports range (1024-49151) are available for
registration through IANA, and MAY be used as service identifiers
upon successful registration. Because registering a port number
for a specific application consumes a fraction of the shared
resource that is the port number registry, IANA will require the
requester to document the intended use of the port number. This
documentation will be input to the "Expert Review" allocation
procedure [RFC5226], by which IANA will have a technical expert
review the request to determine whether to grant the registration.
The submitted documentation MUST explain why using a port number
in the Dynamic Ports range is unsuitable for the given
application. Ports in the User Ports range may also be assigned
under the "IETF Review" or "IESG Approval" allocation procedures
[RFC5226], which is how most assignments for IETF protocols are
handled.
o Ports in the System Ports range (0-1023) are also available for
registration through IANA. Because the System Ports range is both
the smallest and the most densely allocated, the requirements for
new allocations are more strict than those for the User Ports
range, and will only be granted under the "IETF Review" or "IESG
Approval" allocation procedures [RFC5226]. A request for a System
Port number MUST document *both* why using a port number from the
User Ports is unsuitable *and* why using a port number from the
Dynamic Ports ranges is unsuitable for that application.
8.2. Service Name and Port Number De-Registration
The Registrant of a granted port number assignment can return the
port number to IANA at any time if they no longer have a need for it.
The port number will be de-registered and will be marked as Reserved.
IANA should not re-assign port numbers that have been de-registered
until all unassigned port numbers in the specific range have been
assigned.
Before proceeding with a port number de-registration, IANA needs to Before proceeding with a port number de-registration, IANA needs to
reasonably establish that the value is actually no longer in use. reasonably establish that the value is actually no longer in use.
Because there is much less danger of exhausting the service name Because there is much less danger of exhausting the service name
space compared to the port number space, it is RECOMMENDED that a space compared to the port number space, it is RECOMMENDED that a
given service name remain assigned even after all associated port given service name remain assigned even after all associated port
number assignments have become de-registered. Under this policy, it number assignments have become de-registered. Under this policy, it
will appear in the registry as if it had been created through a will appear in the registry as if it had been created through a
service name registration request that did not include any port service name registration request that did not include any port
numbers. numbers.
On rare occasions, it may still be useful to de-register a service On rare occasions, it may still be useful to de-register a service
name. In such cases, IANA will mark the service name as Reserved. name. In such cases, IANA will mark the service name as Reserved.
IANA will involve their IESG-appointed expert in such cases. IANA will involve their IESG-appointed expert in such cases.
8.3. Port Number and Service Name Re-Use IANA will include a comment in the registry when de-registration
happens to indicate its historic usage.
If the administrative contact of a granted port number assignment no 8.3. Service Name and Port Number Re-Use
longer have a need for the registered number, but would like to re-
use it for a different application, they can submit a request to IANA If the Registrant of a granted port number assignment no longer have
to do so. a need for the assigned number, but would like to re-use it for a
different application, they can submit a request to IANA to do so.
Logically, port number re-use is to be thought of as a de- Logically, port number re-use is to be thought of as a de-
registration (Section 8.2) followed by an immediate re-registration registration (Section 8.2) followed by an immediate re-registration
(Section 8.1) of the same port number for a new application. (Section 8.1) of the same port number for a new application.
Consequently, the information that needs to be provided about the Consequently, the information that needs to be provided about the
proposed new use of the port number is identical to what would need proposed new use of the port number is identical to what would need
to be provided for a new port number allocation for the specific to be provided for a new port number allocation for the specific
ports range. ports range.
Because there is much less danger of exhausting the service name Because there is much less danger of exhausting the service name
skipping to change at page 20, line 32 skipping to change at page 21, line 14
application is NOT RECOMMENDED. application is NOT RECOMMENDED.
IANA needs to carefully review such requests before approving them. IANA needs to carefully review such requests before approving them.
In some instances, the Expert Reviewer will determine that the In some instances, the Expert Reviewer will determine that the
application that the port number was assigned to has found usage application that the port number was assigned to has found usage
beyond the original requester, or that there is a concern that it may beyond the original requester, or that there is a concern that it may
have such users. This determination MUST be made quickly. A have such users. This determination MUST be made quickly. A
community call concerning revocation of a port number (see below) MAY community call concerning revocation of a port number (see below) MAY
be considered, if a broader use of the port number is suspected. be considered, if a broader use of the port number is suspected.
8.4. Port Number and Service Name Revocation 8.4. Service Name and Port Number Revocation
A port number revocation can be thought of as an IANA-initiated de- A port number revocation can be thought of as an IANA-initiated de-
registration (Section 8.2), and has exactly the same effect on the registration (Section 8.2), and has exactly the same effect on the
registry. registry.
Sometimes, it will be clear that a specific port number is no longer Sometimes, it will be clear that a specific port number is no longer
in use and that IANA can revoke it and mark it as Reserved. At other in use and that IANA can revoke it and mark it as Reserved. At other
times, it may be unclear whether a given assigned port number is times, it may be unclear whether a given assigned port number is
still in use somewhere in the Internet. In those cases, IANA must still in use somewhere in the Internet. In those cases, IANA must
carefully consider the consequences of revoking the port number, and carefully consider the consequences of revoking the port number, and
skipping to change at page 21, line 10 skipping to change at page 21, line 40
with the Expert Reviewer's support, SHALL determine promptly after with the Expert Reviewer's support, SHALL determine promptly after
the end of the community call whether revocation should proceed and the end of the community call whether revocation should proceed and
then communicate their decision to the community. This procedure then communicate their decision to the community. This procedure
typically involves similar steps to de-registration except that it is typically involves similar steps to de-registration except that it is
initiated by IANA. initiated by IANA.
Because there is much less danger of exhausting the service name Because there is much less danger of exhausting the service name
space compared to the port number space, revoking service names is space compared to the port number space, revoking service names is
NOT RECOMMENDED. NOT RECOMMENDED.
8.5. Port Number and Service Name Transfers 8.5. Service Name and Port Number Transfers
The value of port numbers and service names is defined by their The value of service names and port numbers is defined by their
careful management as a shared Internet resource, whereas enabling careful management as a shared Internet resource, whereas enabling
transfer allows the potential for associated monetary exchanges. As transfer allows the potential for associated monetary exchanges. As
a result, the IETF does not permit port number or service name a result, the IETF does not permit service name or port number
assignments to be transferred between parties, even when they are assignments to be transferred between parties, even when they are
mutually consenting. mutually consenting.
The appropriate alternate procedure is a coordinated de-registration The appropriate alternate procedure is a coordinated de-registration
and registration: The new party requests the port number or service and registration: The new party requests the service name or port
name via a registration and the previous party releases its number via a registration and the previous party releases its
assignment via the de-registration procedure outlined above. assignment via the de-registration procedure outlined above.
With the help of their IESG-appointed Expert Reviewer, IANA SHALL With the help of their IESG-appointed Expert Reviewer, IANA SHALL
carefully determine if there is a valid technical, operational or carefully determine if there is a valid technical, operational or
managerial reason to grant the requested new assignment. managerial reason to grant the requested new assignment.
8.6. Maintenance Issues 8.6. Maintenance Issues
In addition to the formal procedures described above, updates to the In addition to the formal procedures described above, updates to the
Description and Technical Contact information are coordinated by IANA Description and Contact information are coordinated by IANA in an
in an informal manner, and may be initiated by either the registrant informal manner, and may be initiated by either the registrant or by
or by IANA, e.g., by the latter requesting an update to current IANA, e.g., by the latter requesting an update to current contact
contact information. (Note that Registration Administrative Contact information. (Note that Registrant cannot be changed; see
cannot be changed; see Section 8.5 above.) Section 8.5 above.)
8.7. Disagreements
In the case of disagreements around any request there is the
possibility of appeal following the normal appelas process for IANA
registrations as defined by Section 7 of "Guidelines for Writing an
IANA Considerations Section in RFCs" [RFC5226].
9. Security Considerations 9. Security Considerations
The IANA guidelines described in this document do not change the The IANA guidelines described in this document do not change the
security properties of UDP, TCP, SCTP, or DCCP. security properties of UDP, TCP, SCTP, or DCCP.
Assignment of a port number or service name does not in any way imply Assignment of a service name or port number does not in any way imply
an endorsement of an application or product, and the fact that an endorsement of an application or product, and the fact that
network traffic is flowing to or from a registered port number does network traffic is flowing to or from an assigned port number does
not mean that it is "good" traffic, or even that it is used by the not mean that it is "good" traffic, or even that it is used by the
assigned service. Firewall and system administrators should choose assigned service. Firewall and system administrators should choose
how to configure their systems based on their knowledge of the how to configure their systems based on their knowledge of the
traffic in question, not whether there is a port number or service traffic in question, not based on whether or not there is an assigned
name registered or not. service name or port number.
Services are expected to include support for security, either as Services are expected to include support for security, either as
default or dynamically negotiated in-band. The use of separate port default or dynamically negotiated in-band. The use of separate
number or service name assignments for secure and insecure variants service name or port number assignments for secure and insecure
of the same service is to be avoided in order to discourage the variants of the same service is to be avoided in order to discourage
deployment of insecure services. the deployment of insecure services.
10. IANA Considerations 10. IANA Considerations
This document obsoletes Sections 8 and 9.1 of the March 2000 IANA This document obsoletes Sections 8 and 9.1 of the March 2000 IANA
Allocation Guidelines [RFC2780]. Allocation Guidelines [RFC2780].
Upon approval of this document, IANA is requested to contact the Upon approval of this document, IANA is requested to contact Stuart
maintainer of the [SRVREG] registry, in order to merge the contents Cheshire, maintainer of the independent service name registry
of that private registry into the official IANA registry. It is [SRVREG], in order to merge the contents of that private registry
expected that the contents of [SRVREG] will at that time be replaced into the official IANA registry. It is expected that the independent
with pointers to the IANA registry and to this RFC. registry web page will be updated with pointers to the IANA registry
and to this RFC.
IANA is instructed to create a new service name entry in the port IANA is instructed to create a new service name entry in the service
number registry [PORTREG] for any entry in the "Protocol and Service name and port number registry [PORTREG] for any entry in the
Names" registry [PROTSERVREG] that does not already have one "Protocol and Service Names" registry [PROTSERVREG] that does not
assigned. already have one assigned.
IANA is also instructed to indicate which service name aliases in the IANA is also instructed to indicate in the Assignment Notes for "www"
existing registry are the primary aliases (see Section 5). and "www-http" that they are duplicate terms that refer to the "http"
service, and should not be used for discovery purposes. For this
conceptual service (human-readable web pages served over HTTP) the
correct service name to use for service discovery purposes is "http"
(see Section 5).
10.1. Service Name Consistency 10.1. Service Name Consistency
Section 8.1 defines which character strings are well-formed service Section 8.1 defines which character strings are well-formed service
names, which until now had not been clearly defined. The definition names, which until now had not been clearly defined. The definition
in Section 8.1 was chosen to allow maximum compatibility of service in Section 8.1 was chosen to allow maximum compatibility of service
names with current and future service discovery mechanisms. names with current and future service discovery mechanisms.
As of August 5, 2009 approximately 98% of the so-called "Short Names" As of August 5, 2009 approximately 98% of the so-called "Short Names"
from existing port number registrations [PORTREG] meet the rules for from existing port number registrations [PORTREG] meet the rules for
legal service names stated in Section 8.1, and hence will be used legal service names stated in Section 8.1, and hence for these
unmodified. services their service name will be exactly the same as their "Short
Name".
The remaining approximately 2% of the exiting "Short Names" are not The remaining approximately 2% of the exiting "Short Names" are not
suitable to be used directly as well-formed service names because suitable to be used directly as well-formed service names because
they contain illegal characters such as asterisks, dots, pluses, they contain illegal characters such as asterisks, dots, pluses,
slashes, or underscores. All existing "Short Names" conform to the slashes, or underscores. All existing "Short Names" conform to the
length requirement of 15 characters or fewer. For these unsuitable length requirement of 15 characters or fewer. For these unsuitable
"Short Names", listed in the table below, the service name will be "Short Names", listed in the table below, the service name will be
the Short Name with any illegal characters replaced by hyphens. IANA the Short Name with any illegal characters replaced by hyphens. IANA
SHALL add an entry to the registry giving the new well-formed primary SHALL add an entry to the registry giving the new well-formed primary
service name for the existing service, that otherwise duplicates the service name for the existing service, that otherwise duplicates the
original assignment information. In the description field of this original assignment information. In the description field of this
new entry giving the primary service name, IANA SHALL record that it new entry giving the primary service name, IANA SHALL record that it
assigns a well-formed service name for the previous service and assigns a well-formed service name for the previous service and
reference the original assignment. In the description field of the reference the original assignment. In the Assignment Notes field of
original assignment, IANA SHALL add a note that this entry is an the original assignment, IANA SHALL add a note that this entry is an
alias to the new well-formed service name, and that the old service alias to the new well-formed service name, and that the old service
name is historic, not usable for use with many common service name is historic, not usable for use with many common service
discovery mechanisms. discovery mechanisms.
Names containing illegal characters to be replaced by hyphens: Names containing illegal characters to be replaced by hyphens:
+----------------+-----------------+-----------------+ +----------------+-----------------+-----------------+
| 914c/g | acmaint_dbd | acmaint_transd | | 914c/g | acmaint_dbd | acmaint_transd |
| atex_elmd | avanti_cdp | badm_priv | | atex_elmd | avanti_cdp | badm_priv |
| badm_pub | bdir_priv | bdir_pub | | badm_pub | bdir_priv | bdir_pub |
skipping to change at page 24, line 48 skipping to change at page 25, line 46
| universe_suite | veritas_pbx | vision_elmd | | universe_suite | veritas_pbx | vision_elmd |
| vision_server | wrs_registry | z39.50 | | vision_server | wrs_registry | z39.50 |
+----------------+-----------------+-----------------+ +----------------+-----------------+-----------------+
Following the example set by the "application/whoispp-query" MIME Following the example set by the "application/whoispp-query" MIME
Content-Type [RFC2957], the service name for "whois++" will be Content-Type [RFC2957], the service name for "whois++" will be
"whoispp". "whoispp".
10.2. Port Numbers for SCTP and DCCP Experimentation 10.2. Port Numbers for SCTP and DCCP Experimentation
Two Well Known UDP and TCP ports, 1021 and 1022, have been reserved Two System UDP and TCP ports, 1021 and 1022, have been reserved for
for experimental use [RFC4727]. This document registers the same experimental use [RFC4727]. This document assigns the same port
port numbers for SCTP and DCCP, and also instructs IANA to numbers for SCTP and DCCP, updates the TCP and UDP registrations, and
automatically register these two port numbers for any new transport also instructs IANA to automatically assign these two port numbers
protocol that will in the future share the port number namespace. for any future transport protocol with a similar 16-bit port number
namespace.
Note that these port numbers are meant for temporary experimentation Note that these port numbers are meant for temporary experimentation
and development in controlled environments. Before using these port and development in controlled environments. Before using these port
numbers, carefully consider the advice in Section 6.1 in this numbers, carefully consider the advice in Section 6.1 in this
document, as well as in Sections 1 and 1.1 of "Assigning Experimental document, as well as in Sections 1 and 1.1 of "Assigning Experimental
and Testing Numbers Considered Useful" [RFC3692]. Most importantly, and Testing Numbers Considered Useful" [RFC3692]. Most importantly,
application developers must request a permanent port number application developers must request a permanent port number
assignment from IANA as described in Section 8.1 before any kind of assignment from IANA as described in Section 8.1 before any kind of
non-experimental deployment. non-experimental deployment.
+-------------------------------------+----------------------------+ +--------------------+----------------------------+
| Registration Administrative Contact | IETF <iesg@ietf.org> | | Registrant | IETF <iesg@ietf.org> |
| Registration Technical Contact | IESG <iesg@ietf.org> | | Contact | IESG <iesg@ietf.org> |
| Service Name | exp1 | | Service Name | exp1 |
| Port Number | 1021 | | Port Number | 1021 |
| Transport Protocol | SCTP, DCCP | | Transport Protocol | DCCP, SCTP, TCP, UDP |
| Description | RFC3692-style Experiment 1 | | Description | RFC3692-style Experiment 1 |
| Reference | [RFCyyyy] | | Reference | [RFCyyyy],RFC 4727] |
+-------------------------------------+----------------------------+ +--------------------+----------------------------+
+-------------------------------------+----------------------------+ +--------------------+----------------------------+
| Registration Administrative Contact | IETF <iesg@ietf.org> | | Registrant | IETF <iesg@ietf.org> |
| Registration Technical Contact | IESG <iesg@ietf.org> | | Contact | IESG <iesg@ietf.org> |
| Service Name | exp2 | | Service Name | exp2 |
| Port Number | 1022 | | Port Number | 1022 |
| Transport Protocol | SCTP, DCCP | | Transport Protocol | DCCP, SCTP, TCP, UDP |
| Description | RFC3692-style Experiment 2 | | Description | RFC3692-style Experiment 2 |
| Reference | [RFCyyyy] | | Reference | [RFCyyyy], [RFC4727] |
+-------------------------------------+----------------------------+ +--------------------+----------------------------+
[RFC Editor Note: Please change "yyyy" to the RFC number allocated to [RFC Editor Note: Please change "yyyy" to the RFC number allocated to
this document before publication.] this document before publication.]
10.3. Updates to DCCP Registries 10.3. Updates to DCCP Registries
This document updates the IANA allocation procedures for the DCCP This document updates the IANA allocation procedures for the DCCP
Port Number and DCCP Service Codes Registries [RFC4340]. Port Number and DCCP Service Codes Registries [RFC4340].
10.3.1. DCCP Service Code Registry 10.3.1. DCCP Service Code Registry
skipping to change at page 26, line 14 skipping to change at page 27, line 14
o IANA should feel free to contact the DCCP Expert Reviewer with o IANA should feel free to contact the DCCP Expert Reviewer with
questions on any registry, regardless of the registry policy, for questions on any registry, regardless of the registry policy, for
clarification or if there is a problem with a request [RFC4340]. clarification or if there is a problem with a request [RFC4340].
10.3.2. DCCP Port Numbers Registry 10.3.2. DCCP Port Numbers Registry
The DCCP ports registry is defined by Section 19.9 of the DCCP The DCCP ports registry is defined by Section 19.9 of the DCCP
specification [RFC4340]. Allocations in this registry require prior specification [RFC4340]. Allocations in this registry require prior
allocation of a Service Code. Not all Service Codes require IANA- allocation of a Service Code. Not all Service Codes require IANA-
registered ports. This document updates that section by extending assigned ports. This document updates that section by extending the
the guidelines given there in the following way: guidelines given there in the following way:
o IANA should normally assign a value in the range 1024-49151 to a o IANA should normally assign a value in the range 1024-49151 to a
DCCP server port. IANA allocation requests to allocate port DCCP server port. IANA allocation requests to allocate port
numbers in the Well Known Ports range (0 through 1023), require an numbers in the System Ports range (0 through 1023), require an
"IETF Review" [RFC5226] prior to allocation by IANA [RFC4340]. "IETF Review" [RFC5226] prior to allocation by IANA [RFC4340].
o IANA MUST NOT allocate more than one DCCP server port to a single o IANA MUST NOT allocate more than one DCCP server port to a single
service code value. service code value.
o The allocation of multiple service codes to the same DCCP port is o The allocation of multiple service codes to the same DCCP port is
allowed, but subject to expert review. allowed, but subject to expert review.
o The set of Service Code values associated with a DCCP server port o The set of Service Code values associated with a DCCP server port
should be recorded in the ports registry. should be recorded in the service name and port number registry.
o A request for additional Service Codes to be associated with an o A request for additional Service Codes to be associated with an
already allocated Port Number requires Expert Review. These already allocated Port Number requires Expert Review. These
requests will normally be accepted when they originate from the requests will normally be accepted when they originate from the
contact associated with the port registration. In other cases, contact associated with the port registration. In other cases,
these applications will be expected to use an unallocated port, these applications will be expected to use an unallocated port,
when this is available. when this is available.
The DCCP specification [RFC4340] notes that a short port name MUST be The DCCP specification [RFC4340] notes that a short port name MUST be
associated with each DCCP server port that has been registered. This associated with each DCCP server port that has been assigned. This
document requires that this name MUST be unique. document clarifies that this short port name is the Service Name as
defined here, and this name MUST be unique.
11. Contributors 11. Contributors
Stuart Cheshire (cheshire@apple.com), Alfred Hoenes (ah@tr-sys.de) Alfred Hoenes (ah@tr-sys.de) and Allison Mankin (mankin@psg.com) have
and Allison Mankin (mankin@psg.com) have contributed text and ideas contributed text and ideas to this document.
to this document.
12. Acknowledgments 12. Acknowledgments
The text in Section 10.3 is based on a suggestion originally proposed The text in Section 10.3 is based on a suggestion originally proposed
as a part of [RFC5595] by Gorry Fairhurst. as a part of the DCCP Service Codes document[RFC5595] by Gorry
Fairhurst.
Lars Eggert is partly funded by the Trilogy Project [TRILOGY], a Lars Eggert is partly funded by the Trilogy Project [TRILOGY], a
research project supported by the European Commission under its research project supported by the European Commission under its
Seventh Framework Program. Seventh Framework Program.
13. References 13. References
13.1. Normative References 13.1. Normative References
[ANSI.X3-4.1986] [ANSI.X3-4.1986]
skipping to change at page 28, line 17 skipping to change at page 29, line 19
[I-D.cheshire-dnsext-dns-sd] [I-D.cheshire-dnsext-dns-sd]
Cheshire, S. and M. Krochmal, "DNS-Based Service Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", draft-cheshire-dnsext-dns-sd-06 (work in Discovery", draft-cheshire-dnsext-dns-sd-06 (work in
progress), March 2010. progress), March 2010.
[I-D.cheshire-nat-pmp] [I-D.cheshire-nat-pmp]
Cheshire, S., "NAT Port Mapping Protocol (NAT-PMP)", Cheshire, S., "NAT Port Mapping Protocol (NAT-PMP)",
draft-cheshire-nat-pmp-03 (work in progress), April 2008. draft-cheshire-nat-pmp-03 (work in progress), April 2008.
[I-D.gudmundsson-dnsext-srv-clarify]
Gudmundsson, O. and A. Hoenes, "Clarification of DNS SRV
Owner Names", draft-gudmundsson-dnsext-srv-clarify-00
(work in progress), December 2009.
[IGD] UPnP Forum, "Internet Gateway Device (IGD) V 1.0", [IGD] UPnP Forum, "Internet Gateway Device (IGD) V 1.0",
November 2001. November 2001.
[PORTREG] Internet Assigned Numbers Authority (IANA), "Port Numbers [PORTREG] Internet Assigned Numbers Authority (IANA), "Service Name
Registry", http://www.iana.org/assignments/port-numbers. and Transport Protocol Port Number Registry",
http://www.iana.org/assignments/port-numbers.
[PROTSERVREG] [PROTSERVREG]
Internet Assigned Numbers Authority (IANA), "Protocol and Internet Assigned Numbers Authority (IANA), "Protocol and
Service Names Registry", Service Names Registry",
http://www.iana.org/assignments/service-names. http://www.iana.org/assignments/service-names.
[RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol", [RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol",
STD 9, RFC 959, October 1985. STD 9, RFC 959, October 1985.
[RFC1078] Lottor, M., "TCP port service Multiplexer (TCPMUX)", [RFC1078] Lottor, M., "TCP port service Multiplexer (TCPMUX)",
skipping to change at page 30, line 39 skipping to change at page 31, line 26
4676 Admiralty Way 4676 Admiralty Way
Marina del Rey, CA 90292 Marina del Rey, CA 90292
USA USA
Phone: +1 310 448 9151 Phone: +1 310 448 9151
Email: touch@isi.edu Email: touch@isi.edu
URI: http://www.isi.edu/touch URI: http://www.isi.edu/touch
Magnus Westerlund Magnus Westerlund
Ericsson Ericsson
Torshamsgatan 23 Farogatan 6
Stockholm 164 80 Stockholm 164 80
Sweden Sweden
Phone: +46 8 719 0000 Phone: +46 8 719 0000
Email: magnus.westerlund@ericsson.com Email: magnus.westerlund@ericsson.com
Stuart Cheshire Stuart Cheshire
Apple Inc. Apple Inc.
1 Infinite Loop 1 Infinite Loop
Cupertino, CA 95014 Cupertino, CA 95014
USA USA
Phone: +1 408 974 3207 Phone: +1 408 974 3207
Email: cheshire@apple.com Email: cheshire@apple.com
 End of changes. 130 change blocks. 
506 lines changed or deleted 540 lines changed or added

This html diff was produced by rfcdiff 1.40. The latest version is available from http://tools.ietf.org/tools/rfcdiff/