Transport Area Working Group M. Cotton
Internet-Draft ICANN
Updates: 2780, 2782, 3828, 4340, L. Eggert
4960 (if approved) Nokia
Intended status: BCP J. Touch
Expires: November 27, 2010 USC/ISI
M. Westerlund
Ericsson
S. Cheshire
Apple
May 26, 2010
Internet Assigned Numbers Authority (IANA) Procedures for the Management
of the Transport Protocol Port Number and Service Name Registry
draft-ietf-tsvwg-iana-ports-06
Abstract
This document defines the procedures that the Internet Assigned
Numbers Authority (IANA) uses when handling registration and other
requests related to the transport protocol port number and service
name registry. It also discusses the rationale and principles behind
these procedures and how they facilitate the long-term sustainability
of the registry.
This document updates IANA's procedures by obsoleting Sections 8 and
9.1 of the IANA allocation guidelines [RFC2780], it updates the IANA
allocation procedures for UDP-Lite [RFC3828], DCCP [RFC4340] and SCTP
[RFC4960], it updates the DNS SRV specification [RFC2782] to clarify
what a service name is and how it is registered.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on November 27, 2010.
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Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
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Without obtaining an adequate license from the person(s) controlling
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not be created outside the IETF Standards Process, except to format
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Conventions Used in this Document . . . . . . . . . . . . . . 7
5. Service Names . . . . . . . . . . . . . . . . . . . . . . . . 8
5.1. Service Name Syntax . . . . . . . . . . . . . . . . . . . 9
5.2. Service Name Usage in DNS SRV Records . . . . . . . . . . 9
6. Port Number Ranges . . . . . . . . . . . . . . . . . . . . . . 10
6.1. Port Numbers and Service Names for Experimentation . . . . 11
7. Principles for Port Number and Service Name Registry
Management . . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Past Principles . . . . . . . . . . . . . . . . . . . . . 12
7.2. Updated Principles . . . . . . . . . . . . . . . . . . . . 12
7.3. Variances for Specific Port Number Ranges . . . . . . . . 15
8. IANA Procedures for Managing the Port Number and Service
Name Registry . . . . . . . . . . . . . . . . . . . . . . . . 16
8.1. Port Number and Service Name Registration . . . . . . . . 16
8.2. Port Number and Service Name De-Registration . . . . . . . 19
8.3. Port Number and Service Name Re-Use . . . . . . . . . . . 19
8.4. Port Number and Service Name Revocation . . . . . . . . . 20
8.5. Port Number and Service Name Transfers . . . . . . . . . . 21
8.6. Maintenance Issues . . . . . . . . . . . . . . . . . . . . 21
9. Security Considerations . . . . . . . . . . . . . . . . . . . 21
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 22
10.1. Service Name Consistency . . . . . . . . . . . . . . . . . 22
10.2. Port Numbers for SCTP and DCCP Experimentation . . . . . . 24
10.3. Updates to DCCP Registries . . . . . . . . . . . . . . . . 25
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 26
12. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 26
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 27
13.1. Normative References . . . . . . . . . . . . . . . . . . . 27
13.2. Informative References . . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 29
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1. Introduction
For many years, the allocation and registration of new port number
values and service names for use with the Transmission Control
Protocol (TCP) [RFC0793] and the User Datagram Protocol (UDP)
[RFC0768] have had less than clear guidelines. New transport
protocols have been added - the Stream Control Transmission Protocol
(SCTP) [RFC4960] and the Datagram Congestion Control Protocol (DCCP)
[RFC4342] - and new mechanisms like DNS SRV records [RFC2782] have
been developed, each with separate registries and separate
guidelines. The community recognized the need for additional
procedures beyond just assignment; notably modification, revocation,
and release.
A key factor of this procedural streamlining is to establish
identical registration procedures for all IETF transport protocols.
This document brings the IANA procedures for TCP and UDP in line with
those for SCTP and DCCP, resulting in a single process that
requesters and IANA follow for all requests for all transport
protocols, including those not yet defined.
In addition to detailing the IANA procedures for the initial
assignment of port numbers and service names, this document also
specifies post-assignment procedures that until now have been handled
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
for one application that is no longer in use for another application,
and the procedure by which IANA can unilaterally revoke a prior port
number registration. Section 8 discusses the specifics of these
procedures and processes that requesters and IANA follow for all
requests for all current and future transport protocols.
It is important to note that ownership of registered port numbers and
service names remains with IANA. For protocols developed by IETF
working groups, IANA now also offers a method for the "early"
assignment of port numbers and service names [RFC4020], as described
in Section 8.1.
This document updates IANA's procedures for UDP and TCP port numbers
by obsoleting Sections 8 and 9.1 of the IANA allocation guidelines
[RFC2780]. (Note that different sections of the IANA allocation
guidelines, relating to the protocol field values in IPv4 header,
were also updated in February 2008 [RFC5237].) This document also
updates the IANA allocation procedures for DCCP [RFC4340] and SCTP
[RFC4960].
The Lightweight User Datagram Protocol (UDP-Lite) [RFC5237] shares
the port space with UDP. The UDP-Lite specification says: "UDP-Lite
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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
of the UDP-Lite procedures.
This document also clarify what a service name is and how it is
registered. This will impact the DNS SRV specification, because that
specification merely makes a brief mention that the symbolic names of
services are defined in "Assigned Numbers" [RFC1700], without stating
to which section of that 230-page document it refers. The DNS SRV
specification may have been referring to the list of Port Assignments
(known as /etc/services on Unix), or to the "Protocol And Service
Names" section, or to both, or to some other section. Furthermore,
"Assigned Numbers" is now obsolete [RFC3232] and has now been
replaced by on-line registries [PORTREG][PROTSERVREG]. There are
additional updates and clarifications on how DNS SRV utilize the
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
IETF does not undertake very often. If a new transport protocol is
standardized in the future, for the purpose of uniformity it is
expected to follow as much as possible the guidelines and practices
around using port numbers and service names.
2. Motivation
Information about the registration procedures for the port registry
has existed in three locations: the forms for requesting port number
registrations on the IANA web site [SYSFORM] [USRFORM], an
introductory text section in the file listing the port number
registrations themselves [PORTREG], and two brief sections of the
IANA Allocation Guidelines [RFC2780].
Similarly, the procedures surrounding service names have been
historically unclear. Service names were originally created as
mnemonic identifiers for port numbers without a well-defined syntax,
beyond the 14-character limit mentioned on the IANA website [SYSFORM]
[USRFORM]. Even that length limit has not been consistently applied,
and some assigned service names are 15 characters long. When service
identification via DNS SRV RRs was introduced, the requirement by
IANA to only assign service names and port numbers in combination,
led to the creation of an ad hoc service name registry outside of the
control of IANA [SRVREG].
This document aggregates all this scattered information into a single
reference that aligns and clearly defines the management procedures
for both port numbers and service names. It gives more detailed
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guidance to prospective requesters of ports and service names than
the existing documentation, and it streamlines the IANA procedures
for the management of the registry, so that management requests can
complete in a timely manner.
This document defines rules for registration of service names without
associated port numbers, for such usages as DNS SRV records
[RFC2782], which was not possible under the previous IANA procedures.
The document also merges service name registrations from the non-IANA
ad hoc registry [SRVREG] and from the IANA "Protocol and Service
Names" registry [PROTSERVREG] into the IANA "Port and Service Name"
registry [PORTREG], which from here on is the single authoritative
registry for service names and port numbers.
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
stewards of the port number registry. TCP and UDP have been a
remarkable success over the last decades. Thousands of applications
and application-level protocols have registered ports and service
names for their use, and there is every reason to believe that this
trend will continue into the future. It is hence extremely important
that management of the registry follow principles that ensure its
long-term usefulness as a shared resource. Section 7 discusses these
principles in detail.
3. Background
The Transmission Control Protocol (TCP) [RFC0793] and the User
Datagram Protocol (UDP) [RFC0768] have enjoyed a remarkable success
over the decades as the two most widely used transport protocols on
the Internet. They have relied on the concept of "ports" as logical
entities for Internet communication. Ports serve two purposes:
first, they provide a demultiplexing identifier to differentiate
transport sessions between the same pair of endpoints, and second,
they may also identify the application protocol and associated
service to which processes bind. Newer transport protocols, such as
the Stream Control Transmission Protocol (SCTP) [RFC4960] and the
Datagram Congestion Control Protocol (DCCP) [RFC4342] have adopted
the concept of ports for their communication sessions and use 16-bit
port numbers in the same way as TCP and UDP (and UDP-Lite [RFC3828],
a variant of UDP).
Port numbers are the original and most widely used means for
application and service identification on the Internet. Ports are
16-bit numbers, and the combination of source and destination port
numbers together with the IP addresses of the communicating end
systems uniquely identifies a session of a given transport protocol.
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Port numbers are also known by their corresponding service names such
as "telnet" for port number 23 and "http" (and the "www" alias) for
port number 80.
Hosts running services, hosts accessing services on other hosts, and
intermediate devices (such as firewalls and NATs) that restrict
services need to agree on which service corresponds to a particular
destination port. Although this is ultimately a local decision with
meaning only between the endpoints of a connection, it is common for
many services to have a default port upon which those servers usually
listen, when possible, and these ports are recorded by the Internet
Assigned Numbers Authority (IANA) through the port number registry
[PORTREG].
Over time, the assumption that a particular port number necessarily
implies a particular service may become less true. For example,
multiple instances of the same service on the same host cannot
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
external side of the NAT gateway, whether using static port mappings
configured by hand by the user, or dynamic port mappings configured
automatically using a port mapping protocol NAT Port Mapping Protocol
(NAT-PMP) [I-D.cheshire-nat-pmp] or Internet Gateway Device (IGD)
[IGD].
Applications either use numeric port numbers directly, look up port
numbers based on service names via system calls such as
getservbyname() on UNIX, look up port numbers by performing queries
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
Service Multiplexer (TCPMUX) [RFC1078].
Designers of applications and application-level protocols may apply
to IANA for an assigned port number and service name for a specific
application, and may - after successful registration - assume that no
other application will use that port number or service name for its
communication sessions. Alternatively, application designers may
also ask for only an assigned service name, if their application does
not require a fixed port number. The latter alternative is
encouraged when possible, in order to conserve the more limited port
number space. This includes, for example, applications that use DNS
SRV records to look up port numbers at runtime.
4. Conventions Used in this Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
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document are to be interpreted as described in [RFC2119].
5. Service Names
Service names are the unique key in the Port and Service Name
registry. This unique symbolic name for a service may also be used
for other purposes, such as in DNS SRV records [RFC2782]. Within the
registry, this unique key ensures that different services can be
unambiguously distinguished, thus preventing name collisions and
avoiding confusion about who is the administrative contact 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
transport protocol and port. There are two valid reasons for
allowing service name aliases:
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
another service, and an in-band mechanisms exists for determining
if the extension is present or not. One example is port 3478,
which has the service name aliases "stun" and "turn". TURN
[RFC5766] is an extension to the STUN [RFC5389] service. TURN-
enabled clients wishing to locate TURN servers could attempt to
discover "stun" services and then checking in-band if the server
supports TURN, but this is inefficient. Enabling them to directly
query for "turn" servers by name is a better approach. (Note that
TURN servers in this case should also be locatable via a "stun"
discovery, because every TURN server is also a STUN server.)
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Service names are assigned on a "first come, first served" basis, as
described in Section 8.1. Names should be brief and informative,
avoiding words or abbreviations that are redundant in the context of
the registry (e.g., "port", "service", "protocol", etc.) Names
referring to discovery services, e.g., using multicast or broadcast
to identify endpoints capable of a given service, SHOULD use an
easily identifiable suffix (e.g., "-disc").
5.1. Service Name Syntax
Valid service names MUST contain only these US-ASCII [ANSI.X3-4.1986]
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
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]:
SRVNAME = (ALPHA / *([HYPHEN] ALNUM)) /
(1*DIGIT ((HYPHEN ALNUM) / ALPHA) *([HYPHEN] ALNUM))
ALNUM = ALPHA / DIGIT ; A-Z, a-z, 0-9
HYPHEN = %x2d ; "-"
ALPHA = <See [RFC5234]>
DIGIT = <See [RFC5234]>
5.2. Service Name Usage in DNS SRV Records
The DNS SRV specification [RFC2782] requests that the Service Label
part of the owner name of DNS SRV records includes a "Service"
element, defined to be "the symbolic name of the desired service",
but did not state precisely which part of the IANA database (i.e.
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
as defined herein. The service name SHOULD be registered with IANA
and recorded in the Service Names and Port Numbers registry
[PORTREG]. This is needed to ensure that only a single registry of
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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
specified in the documentation set of the application/service. In
the absence of such specification, prospective clients of a given
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
TCP, UDP, UDP-Lite, SCTP and DCCP use 16-bit namespaces for their
port number registries. The port registries for all these transport
protocols are subdivided into three ranges of numbers, and
Section 7.3 describes the IANA procedures for each range in detail:
o the Well Known Ports, also known as the System Ports, from 0-1023
(assigned by IANA)
o the Registered Ports, also known as the User Ports, from 1024-
49151 (assigned by IANA)
o the Dynamic Ports, also known as the Private Ports, from 49152-
65535 (never assigned)
Of the assignable port ranges (Well Known and Registered, i.e., port
numbers 0-49151), individual port numbers are in one of three states
at any given time:
o Assigned: Assigned port numbers are currently allocated to the
service indicated in the registry.
o Unassigned: Unassigned port numbers are currently available for
assignment upon request, as per the procedures outlined in this
document.
o Reserved: Reserved port numbers are not available for regular
assignment; they are "assigned to IANA" for special purposes.
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Reserved port numbers include values at the edges of each range,
e.g., 0, 1023, 1024, etc., which may be used to extend these
ranges or the overall port number space in the future.
In order to keep the size of the registry manageable, IANA typically
only records the Assigned and Reserved port numbers and service names
in the registry. Unassigned values are typically not explicitly
listed.
As a data point, when this document was written, approximately 76% of
the TCP and UDP Well Known Ports were assigned, and approximately 9%
of the Registered Ports were assigned. (As noted, Dynamic Ports are
never assigned.)
6.1. Port Numbers and Service Names for Experimentation
Of the Well Known ports, two TCP and UDP port numbers (1021 and
1022), together with their respective service names ("exp1" and
"exp2"), have been assigned for experimentation with new applications
and application-layer protocols that require a port number in the
assigned ports ranges [RFC4727].
Please refer to Sections 1 and 1.1 of "Assigning Experimental and
Testing Numbers Considered Useful" [RFC3692] for how these
experimental port numbers are to be used.
This document registers the same two port numbers and service names
for experimentation with new application-layer protocols over SCTP
and DCCP in Section 10.2.
Unfortunately, it can be difficult to limit access to these ports.
Users SHOULD take measures to ensure that experimental ports are
connecting to the intended process. For example, users of these
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 byte-stream (e.g., TCP), which is used to confirm that the port
is being used as intended. Such confirmation of intended use is
especially important when these ports are associated with privileged
(e.g., system or administrator) processes.
7. Principles for Port Number and Service Name Registry Management
Management procedures for the port number and service name registry
include allocation of port numbers and service names upon request, as
well as coordination of information about existing allocations. The
latter includes maintaining contact and description information about
assignments, revoking abandoned assignments, and redefining
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assignments when needed. Of these procedures, port number allocation
is most critical, in order to continue to conserve the remaining port
numbers.
As noted earlier, only ~9% of the Registered Port space is currently
assigned. The current rate of assignment is approximately 400 ports/
year, and has remained linear for the past 8 years. At that rate, if
similar conservation continues, this resource will sustain another 85
years of assignment - without the need to resort to reassignment of
released values or revocation. Note that the namespace available for
service names is even larger, which allows for a simpler management
procedures.
7.1. Past Principles
Before the publication of this document, the principles of port
number and service name management followed a few mostly-undocumented
guidelines. They are recorded here for historical purposes, and this
document updates them in Section 7.2. These principles were:
o TCP and UDP ports were simultaneously allocated when either was
requested
o Port numbers were the primary allocation; service names were
informative only, and did not have a well-defined syntax
o Port numbers were conserved informally, and sometimes
inconsistently (e.g., some services were allocated ranges of many
port numbers even where not strictly necessary)
o SCTP and DCCP port number and service name registries were managed
separately from the TCP/UDP registries
o Service names could not be assigned in the ports registry without
assigning a corresponding port number at the same time
This document clarifies and aligns these guidelines in order to more
conservatively manage the limited remaining port number space and to
enable and promote the use of service names for service
identification without associated port numbers, where possible.
7.2. Updated Principles
This section summarizes the basic principles by which IANA handles
the Port and Service Name registry, and attempts to conserve the port
number space. This description is intended to inform applicants
requesting service names and port numbers. IANA decisions are not
required to be bound to these principles, however; other factors may
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come into play, and exceptions may occur where deemed in the best
interest of the Internet.
IANA will begin assigning service names that do not request a
corresponding port number allocation under a simple "First Come,
First Served" policy [RFC5226]. IANA MAY, at its discretion, refer
service name requests to "Expert Review" in cases of mass
registrations or other situations where IANA believes expert review
is advisable.
The basic principle of port number registry management is to conserve
use of the port space where possible. Extensions to support larger
port number spaces would require changing many core protocols of the
current Internet in a way that would not be backward compatible and
interfere with both current and legacy applications. To help ensure
this conservation the policy for any registration request for port
number allocations uses the "Expert Review" policy [RFC5226].
Conservation of the port number space is required because this space
is a limited resource, applications are expected to participate in
the traffic demultiplexing process where feasible. The port numbers
are expected to encode as little information as possible that will
still enable an application to perform further demultiplexing by
itself. In particular:
o IANA will allocate only one assigned port number per service or
application
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
mechanism, or for updated variants of a service)
o IANA will allocate only one assigned port number for all different
types of device using or participating in the same service
o IANA will allocate port numbers only for the transport protocol(s)
explicitly named in an registration request
o IANA may recover unused port numbers, via the new procedures of
de-registration, revocation, and transfer
A given service is expected to further demultiplex messages where
possible. For example, applications and protocols are expected to
include in-band version information, so that future versions of the
application or protocol can share the same allocated port.
Applications and protocols are also expected to be able to
efficiently use a single allocated port for multiple sessions, either
by demultiplexing multiple streams within one port, or using the
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allocated port to coordinate using dynamic ports for subsequent
exchanges (e.g., in the spirit of FTP [RFC0959]).
Ports are used in various ways, notably:
o as endpoint process identifiers
o as application protocol identifiers
o for firewall filtering purposes
The process and protocol identifier use suggests that anything a
single process can demultiplex, or that can be encoded into a single
protocol, should be. The firewall filtering use suggests that some
uses that could be multiplexed or encoded must be separated to allow
for firewall management. Note that this latter use is much less
sound, because port numbers have meaning only for the two endpoints
involved in a connection, and drawing conclusions about the service
that generated a given flow based on observed port numbers is not
always reliable. Further, previous separation of protocol variants
based on security capabilities (e.g., HTTP on TCP port 80 vs. HTTPS
on TCP port 443) is not recommended for new protocols, because all
should be security-capable and capable of negotiating the use of
security in-band.
IANA will begin assigning port numbers for only those transport
protocols explicitly included in a registration request. This ends
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
only one of these transport protocols. The new allocation procedure
conserves resources by allocating a port number to an application for
only those transport protocols (TCP, UDP, SCTP and/or DCCP) it
actually uses. The port number will be marked as Reserved - instead
of Assigned - in the port number registries of the other transport
protocols. When applications start supporting the use of some of
those additional transport protocols, the administrative contact for
the registration MUST request IANA to convert the reservation into 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
another transport protocol without asking IANA to convert the
reservation into an assignment.
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
for assignment. This is part of the motivation to not automatically
assigning ports for other transport protocols than the requested
ones. This will allow more ports to be available for assignment at
that point. It also shows the importance to register the transport
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protocols that are in fact used.
Conservation of port numbers is improved by procedures that allow
previously allocated port numbers to become Unassigned, either
through de-registration or through revocation, and by a procedure
that lets application designers transfer an allocated but unused port
number to a new application. Section 8 describes these procedures,
which so far were undocumented. Port number conservation is also
improved by recommending that applications that do not require an
allocated port chose this option and register only a service name.
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].
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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
Registry
This section describes the process for requests associated with
IANA's management of the port number and service name registry. Such
requests include initial registration, de-registration, re-use,
changes to the service name, as well as updates to the contact
information or description associated with an assignment. Revocation
is initiated by IANA.
8.1. Port Number and Service Name Registration
Registration refers to the allocation of port numbers or service
names to applicants. All such registrations are made from port
numbers or service names that are Unassigned or Reserved at the time
of the allocation. Unassigned numbers and names are allocated as
needed, and without further explanation. Reserved numbers and names
are assigned only after review by IANA and the IETF, and are
accompanied by a statement explaining the reason a Reserved number or
name is appropriate for this action.
When a registration for one or more transport protocols is approved,
the port number for any non-requested transport protocol(s) will be
marked as Reserved. IANA SHOULD NOT assign that port number to any
other application or service until no other port numbers remain
Unassigned in the requested range. The current administrative
contact for a port number MAY register these Reserved port numbers
for other transport 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.
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A port number or service name registration request contains some or
all of the following information. The combination of service name
and transport protocol is the unique identifier of a given service:
Service Name (REQUIRED)
Transport Protocol(s) (REQUIRED)
Registration Administrative Contact (REQUIRED)
Registration Technical Contact (REQUIRED)
Port Number (OPTIONAL)
Service Code (only REQUIRED for DCCP)
Description (REQUIRED)
Reference (REQUIRED)
Known Unauthorized Uses (OPTIONAL)
Assignment Notes (OPTIONAL)
o Service Name: A desired unique service name for the service
associated with the registration request MUST be provided, for use
in various service selection and discovery mechanisms (including,
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
unique, they MUST NOT be identical to any currently registered
service names in the IANA registry [PORTREG]. Service names are
case-insensitive; they may be provided and entered into the
registry with mixed case (e.g., for clarity), but for the purposes
of comparison, the case is ignored.
o Transport Protocol(s): The transport protocol(s) for which the
allocation is requested MUST be provided. This field is currently
limited to one or more of TCP, UDP, SCTP, and DCCP. This field is
required even for services with no port number.
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
currently Unassigned port number the requester suggests for
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allocation, or the text "ANY", MUST be provided. If only a
service name is to be assigned, this field MUST be empty. If a
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
service code [RFC5595], if the registration request includes DCCP
as a transport protocol, and MUST NOT include a requested DCCP
service code otherwise. Section 19.8 of [RFC4340] defines
requirements and rules for allocation, updated by this document.
o Description: A short description of the service associated with
the registration request is REQUIRED. It should avoid all but the
most well known acronyms.
o Reference: A description of (or a reference to a document
describing) the protocol or application using this port. The
description must include whether the protocol uses either
broadcast, multicast, or anycast communication.
For registrations requesting only a Service Name or a Service Name
and Registered Port, a statement that the protocol is proprietary
and not publicly documented is also acceptable provided that the
above information regarding use of broadcast, multicast, or
anycast is given.
For registration requests for a Registered Port, the registration
request MUST explain why a port number in the Dynamic Ports range
is unsuitable for the given application.
For registration requests for a Well Known Port, the registration
request MUST explain why a port number in the Registered Ports or
Dynamic Ports ranges is unsuitable, and a reference to a stable
protocol specification document MUST be provided. For requests
from IETF Working Groups, IANA MAY accept "Early" registration
requests referencing a sufficiently stable Internet Draft instead
of a published Standards-Track RFC [RFC4020].
o Known Unauthorized Uses: A list of uses by applications or
organizations who are not the assignee. This list may be
augmented by IANA after assignment when unauthorized uses are
reported.
o Assignment Notes: Indications of owner/name change, or any other
assignment process issue. This list may be updated by IANA after
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assignment to help track changes to an assignment, e.g., de-
registration, owner/name changes, etc.
If the registration request is for the addition of a new transport
protocol to an already assigned service name, IANA needs to confirm
with the administrative contact for the existing assignment whether
this addition is appropriate.
If the registration request is for a service name alias (see
Section 5), IANA needs to confirm with the administrative contact for
the existing service name whether the registration of the alias is
appropriate.
When IANA receives a registration request - containing the above
information - that is requesting a port number, IANA SHALL initiate
an "Expert Review" [RFC5226] in order to determine whether an
assignment should be made. For requests that do not include a port
number, IANA SHOULD assign the service name under a simple "First
Come First Served" policy [RFC5226].
8.2. Port Number and Service Name De-Registration
The administrative contact 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 other available port numbers in the
specific range have been assigned.
Before proceeding with a port number de-registration, IANA needs to
reasonably establish that the value is actually no longer in use.
Because there is much less danger of exhausting the service name
space compared to the port number space, it is RECOMMENDED that a
given service name remain assigned even after all associated port
number assignments have become de-registered. Under this policy, it
will appear in the registry as if it had been created through a
service name registration request that did not include any port
numbers.
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.
IANA will involve their IESG-appointed expert in such cases.
8.3. Port Number and Service Name Re-Use
If the administrative contact of a granted port number assignment no
longer have a need for the registered number, but would like to re-
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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-
registration (Section 8.2) followed by an immediate re-registration
(Section 8.1) of the same port number for a new application.
Consequently, the information that needs to be provided about the
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
ports range.
Because there is much less danger of exhausting the service name
space compared to the port number space, it is RECOMMENDED that the
original service name associated with the prior use of the port
number remains assigned, and a new service be created and associated
with the port number. This is again consistent with viewing a re-use
request as a de-registration followed by an immediate re-
registration. Re-using an assigned service name for a different
application is NOT RECOMMENDED.
IANA needs to carefully review such requests before approving them.
In some instances, the Expert Reviewer will determine that the
application that the port number was assigned to has found usage
beyond the original requester, or that there is a concern that it may
have such users. This determination MUST be made quickly. A
community call concerning revocation of a port number (see below) MAY
be considered, if a broader use of the port number is suspected.
8.4. Port Number and Service Name Revocation
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
registry.
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
times, it may be unclear whether a given assigned port number is
still in use somewhere in the Internet. In those cases, IANA must
carefully consider the consequences of revoking the port number, and
SHOULD only do so if there is an overwhelming need.
With the help of their IESG-appointed Expert Reviewer, IANA SHALL
formulate a request to the IESG to issue a four-week community call
concerning the pending port number revocation. The IESG and IANA,
with the Expert Reviewer's support, SHALL determine promptly after
the end of the community call whether revocation should proceed and
then communicate their decision to the community. This procedure
typically involves similar steps to de-registration except that it is
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initiated by IANA.
Because there is much less danger of exhausting the service name
space compared to the port number space, revoking service names is
NOT RECOMMENDED.
8.5. Port Number and Service Name Transfers
The value of port numbers and service names is defined by their
careful management as a shared Internet resource, whereas enabling
transfer allows the potential for associated monetary exchanges. As
a result, the IETF does not permit port number or service name
assignments to be transferred between parties, even when they are
mutually consenting.
The appropriate alternate procedure is a coordinated de-registration
and registration: The new party requests the port number or service
name via a registration and the previous party releases its
assignment via the de-registration procedure outlined above.
With the help of their IESG-appointed Expert Reviewer, IANA SHALL
carefully determine if there is a valid technical, operational or
managerial reason to grant the requested new assignment.
8.6. Maintenance Issues
In addition to the formal procedures described above, updates to the
Description and Technical Contact information are coordinated by IANA
in an informal manner, and may be initiated by either the registrant
or by IANA, e.g., by the latter requesting an update to current
contact information. (Note that Registration Administrative Contact
cannot be changed; see Section 8.5 above.)
9. Security Considerations
The IANA guidelines described in this document do not change the
security properties of UDP, TCP, SCTP, or DCCP.
Assignment of a port number or service name does not in any way imply
an endorsement of an application or product, and the fact that
network traffic is flowing to or from a registered port number does
not mean that it is "good" traffic, or even that it is used by the
assigned service. Firewall and system administrators should choose
how to configure their systems based on their knowledge of the
traffic in question, not whether there is a port number or service
name registered or not.
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Services are expected to include support for security, either as
default or dynamically negotiated in-band. The use of separate port
number or service name assignments for secure and insecure variants
of the same service is to be avoided in order to discourage the
deployment of insecure services.
10. IANA Considerations
This document obsoletes Sections 8 and 9.1 of the March 2000 IANA
Allocation Guidelines [RFC2780].
Upon approval of this document, IANA is requested to contact the
maintainer of the [SRVREG] registry, in order to merge the contents
of that private registry into the official IANA registry. It is
expected that the contents of [SRVREG] will at that time be replaced
with pointers to the IANA registry and to this RFC.
IANA is instructed to create a new service name entry in the port
number registry [PORTREG] for any entry in the "Protocol and Service
Names" registry [PROTSERVREG] that does not already have one
assigned.
IANA is also instructed to indicate which service name aliases in the
existing registry are the primary aliases (see Section 5).
10.1. Service Name Consistency
Section 8.1 defines which character strings are well-formed service
names, which until now had not been clearly defined. The definition
in Section 8.1 was chosen to allow maximum compatibility of service
names with current and future service discovery mechanisms.
As of August 5, 2009 approximately 98% of the so-called "Short Names"
from existing port number registrations [PORTREG] meet the rules for
legal service names stated in Section 8.1, and hence will be used
unmodified.
The remaining approximately 2% of the exiting "Short Names" are not
suitable to be used directly as well-formed service names because
they contain illegal characters such as asterisks, dots, pluses,
slashes, or underscores. All existing "Short Names" conform to the
length requirement of 15 characters or fewer. For these unsuitable
"Short Names", listed in the table below, the service name will be
the Short Name with any illegal characters replaced by hyphens. IANA
SHALL add an entry to the registry giving the new well-formed primary
service name for the existing service, that otherwise duplicates the
original assignment information. In the description field of this
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new entry giving the primary service name, IANA SHALL record that it
assigns a well-formed service name for the previous service and
reference the original assignment. In the description field of 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
name is historic, not usable for use with many common service
discovery mechanisms.
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Names containing illegal characters to be replaced by hyphens:
+----------------+-----------------+-----------------+
| 914c/g | acmaint_dbd | acmaint_transd |
| atex_elmd | avanti_cdp | badm_priv |
| badm_pub | bdir_priv | bdir_pub |
| bmc_ctd_ldap | bmc_patroldb | boks_clntd |
| boks_servc | boks_servm | broker_service |
| bues_service | canit_store | cedros_fds |
| cl/1 | contamac_icm | corel_vncadmin |
| csc_proxy | cvc_hostd | dbcontrol_agent |
| dec_dlm | dl_agent | documentum_s |
| dsmeter_iatc | dsx_monitor | elpro_tunnel |
| elvin_client | elvin_server | encrypted_admin |
| erunbook_agent | erunbook_server | esri_sde |
| EtherNet/IP-1 | EtherNet/IP-2 | event_listener |
| flr_agent | gds_db | ibm_wrless_lan |
| iceedcp_rx | iceedcp_tx | iclcnet_svinfo |
| idig_mux | ife_icorp | instl_bootc |
| instl_boots | intel_rci | interhdl_elmd |
| lan900_remote | LiebDevMgmt_A | LiebDevMgmt_C |
| LiebDevMgmt_DM | mapper-ws_ethd | matrix_vnet |
| mdbs_daemon | menandmice_noh | msl_lmd |
| nburn_id | ncr_ccl | nds_sso |
| netmap_lm | nms_topo_serv | notify_srvr |
| novell-lu6.2 | nuts_bootp | nuts_dem |
| ocs_amu | ocs_cmu | pipe_server |
| pra_elmd | printer_agent | redstorm_diag |
| redstorm_find | redstorm_info | redstorm_join |
| resource_mgr | rmonitor_secure | rsvp_tunnel |
| sai_sentlm | sge_execd | sge_qmaster |
| shiva_confsrvr | sql*net | srvc_registry |
| stm_pproc | subntbcst_tftp | udt_os |
| universe_suite | veritas_pbx | vision_elmd |
| vision_server | wrs_registry | z39.50 |
+----------------+-----------------+-----------------+
Following the example set by the "application/whoispp-query" MIME
Content-Type [RFC2957], the service name for "whois++" will be
"whoispp".
10.2. Port Numbers for SCTP and DCCP Experimentation
Two Well Known UDP and TCP ports, 1021 and 1022, have been reserved
for experimental use [RFC4727]. This document registers the same
port numbers for SCTP and DCCP, and also instructs IANA to
automatically register these two port numbers for any new transport
protocol that will in the future share the port number namespace.
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Note that these port numbers are meant for temporary experimentation
and development in controlled environments. Before using these port
numbers, carefully consider the advice in Section 6.1 in this
document, as well as in Sections 1 and 1.1 of "Assigning Experimental
and Testing Numbers Considered Useful" [RFC3692]. Most importantly,
application developers must request a permanent port number
assignment from IANA as described in Section 8.1 before any kind of
non-experimental deployment.
+-------------------------------------+----------------------------+
| Registration Administrative Contact | IETF <iesg@ietf.org> |
| Registration Technical Contact | IESG <iesg@ietf.org> |
| Service Name | exp1 |
| Port Number | 1021 |
| Transport Protocol | SCTP, DCCP |
| Description | RFC3692-style Experiment 1 |
| Reference | [RFCyyyy] |
+-------------------------------------+----------------------------+
+-------------------------------------+----------------------------+
| Registration Administrative Contact | IETF <iesg@ietf.org> |
| Registration Technical Contact | IESG <iesg@ietf.org> |
| Service Name | exp2 |
| Port Number | 1022 |
| Transport Protocol | SCTP, DCCP |
| Description | RFC3692-style Experiment 2 |
| Reference | [RFCyyyy] |
+-------------------------------------+----------------------------+
[RFC Editor Note: Please change "yyyy" to the RFC number allocated to
this document before publication.]
10.3. Updates to DCCP Registries
This document updates the IANA allocation procedures for the DCCP
Port Number and DCCP Service Codes Registries [RFC4340].
10.3.1. DCCP Service Code Registry
Service Codes are allocated first-come-first-served according to
Section 19.8 of the DCCP specification [RFC4340]. This document
updates that section by extending the guidelines given there in the
following ways:
o IANA MAY assign new Service Codes without seeking Expert Review
using their discretion, but SHOULD seek expert review if a request
seeks more than five Service Codes.
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o IANA should feel free to contact the DCCP Expert Reviewer with
questions on any registry, regardless of the registry policy, for
clarification or if there is a problem with a request [RFC4340].
10.3.2. DCCP Port Numbers Registry
The DCCP ports registry is defined by Section 19.9 of the DCCP
specification [RFC4340]. Allocations in this registry require prior
allocation of a Service Code. Not all Service Codes require IANA-
registered ports. This document updates that section by extending
the guidelines given there in the following way:
o IANA should normally assign a value in the range 1024-49151 to a
DCCP server port. IANA allocation requests to allocate port
numbers in the Well Known Ports range (0 through 1023), require an
"IETF Review" [RFC5226] prior to allocation by IANA [RFC4340].
o IANA MUST NOT allocate more than one DCCP server port to a single
service code value.
o The allocation of multiple service codes to the same DCCP port is
allowed, but subject to expert review.
o The set of Service Code values associated with a DCCP server port
should be recorded in the ports registry.
o A request for additional Service Codes to be associated with an
already allocated Port Number requires Expert Review. These
requests will normally be accepted when they originate from the
contact associated with the port registration. In other cases,
these applications will be expected to use an unallocated port,
when this is available.
The DCCP specification [RFC4340] notes that a short port name MUST be
associated with each DCCP server port that has been registered. This
document requires that this name MUST be unique.
11. Contributors
Stuart Cheshire (cheshire@apple.com), Alfred Hoenes (ah@tr-sys.de)
and Allison Mankin (mankin@psg.com) have contributed text and ideas
to this document.
12. Acknowledgments
The text in Section 10.3 is based on a suggestion originally proposed
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as a part of [RFC5595] by Gorry Fairhurst.
Lars Eggert is partly funded by the Trilogy Project [TRILOGY], a
research project supported by the European Commission under its
Seventh Framework Program.
13. References
13.1. Normative References
[ANSI.X3-4.1986]
American National Standards Institute, "Coded Character
Set - 7-bit American Standard Code for Information
Interchange", ANSI X3.4, 1986.
[RFC0768] Postel, J., "User Datagram Protocol", STD 6, RFC 768,
August 1980.
[RFC0793] Postel, J., "Transmission Control Protocol", STD 7,
RFC 793, September 1981.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2780] Bradner, S. and V. Paxson, "IANA Allocation Guidelines For
Values In the Internet Protocol and Related Headers",
BCP 37, RFC 2780, March 2000.
[RFC3828] Larzon, L-A., Degermark, M., Pink, S., Jonsson, L-E., and
G. Fairhurst, "The Lightweight User Datagram Protocol
(UDP-Lite)", RFC 3828, July 2004.
[RFC4020] Kompella, K. and A. Zinin, "Early IANA Allocation of
Standards Track Code Points", BCP 100, RFC 4020,
February 2005.
[RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram
Congestion Control Protocol (DCCP)", RFC 4340, March 2006.
[RFC4727] Fenner, B., "Experimental Values In IPv4, IPv6, ICMPv4,
ICMPv6, UDP, and TCP Headers", RFC 4727, November 2006.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC5234] Crocker, D. and P. Overell, "Augmented BNF for Syntax
Cotton, et al. Expires November 27, 2010 [Page 27]
Internet-Draft Port Number and Service Name Procedures May 2010
Specifications: ABNF", STD 68, RFC 5234, January 2008.
13.2. Informative References
[I-D.cheshire-dnsext-dns-sd]
Cheshire, S. and M. Krochmal, "DNS-Based Service
Discovery", draft-cheshire-dnsext-dns-sd-06 (work in
progress), March 2010.
[I-D.cheshire-nat-pmp]
Cheshire, S., "NAT Port Mapping Protocol (NAT-PMP)",
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",
November 2001.
[PORTREG] Internet Assigned Numbers Authority (IANA), "Port Numbers
Registry", http://www.iana.org/assignments/port-numbers.
[PROTSERVREG]
Internet Assigned Numbers Authority (IANA), "Protocol and
Service Names Registry",
http://www.iana.org/assignments/service-names.
[RFC0959] Postel, J. and J. Reynolds, "File Transfer Protocol",
STD 9, RFC 959, October 1985.
[RFC1078] Lottor, M., "TCP port service Multiplexer (TCPMUX)",
RFC 1078, November 1988.
[RFC1700] Reynolds, J. and J. Postel, "Assigned Numbers", RFC 1700,
October 1994.
[RFC2782] Gulbrandsen, A., Vixie, P., and L. Esibov, "A DNS RR for
specifying the location of services (DNS SRV)", RFC 2782,
February 2000.
[RFC2957] Daigle, L. and P. Faltstrom, "The application/
whoispp-query Content-Type", RFC 2957, October 2000.
[RFC3232] Reynolds, J., "Assigned Numbers: RFC 1700 is Replaced by
an On-line Database", RFC 3232, January 2002.
Cotton, et al. Expires November 27, 2010 [Page 28]
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[RFC3692] Narten, T., "Assigning Experimental and Testing Numbers
Considered Useful", BCP 82, RFC 3692, January 2004.
[RFC4342] Floyd, S., Kohler, E., and J. Padhye, "Profile for
Datagram Congestion Control Protocol (DCCP) Congestion
Control ID 3: TCP-Friendly Rate Control (TFRC)", RFC 4342,
March 2006.
[RFC4960] Stewart, R., "Stream Control Transmission Protocol",
RFC 4960, September 2007.
[RFC5237] Arkko, J. and S. Bradner, "IANA Allocation Guidelines for
the Protocol Field", BCP 37, RFC 5237, February 2008.
[RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing,
"Session Traversal Utilities for NAT (STUN)", RFC 5389,
October 2008.
[RFC5595] Fairhurst, G., "The Datagram Congestion Control Protocol
(DCCP) Service Codes", RFC 5595, September 2009.
[RFC5766] Mahy, R., Matthews, P., and J. Rosenberg, "Traversal Using
Relays around NAT (TURN): Relay Extensions to Session
Traversal Utilities for NAT (STUN)", RFC 5766, April 2010.
[SRVREG] "DNS SRV Service Types Registry",
http://www.dns-sd.org/ServiceTypes.html.
[SYSFORM] Internet Assigned Numbers Authority (IANA), "Application
for System (Well Known) Port Number",
http://www.iana.org/cgi-bin/sys-port-number.pl.
[TRILOGY] "Trilogy Project", http://www.trilogy-project.org/.
[USRFORM] Internet Assigned Numbers Authority (IANA), "Application
for User (Registered) Port Number",
http://www.iana.org/cgi-bin/usr-port-number.pl.
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Authors' Addresses
Michelle Cotton
Internet Corporation for Assigned Names and Numbers
4676 Admiralty Way, Suite 330
Marina del Rey, CA 90292
USA
Phone: +1 310 823 9358
Email: michelle.cotton@icann.org
URI: http://www.iana.org/
Lars Eggert
Nokia Research Center
P.O. Box 407
Nokia Group 00045
Finland
Phone: +358 50 48 24461
Email: lars.eggert@nokia.com
URI: http://research.nokia.com/people/lars_eggert/
Joe Touch
USC/ISI
4676 Admiralty Way
Marina del Rey, CA 90292
USA
Phone: +1 310 448 9151
Email: touch@isi.edu
URI: http://www.isi.edu/touch
Magnus Westerlund
Ericsson
Torshamsgatan 23
Stockholm 164 80
Sweden
Phone: +46 8 719 0000
Email: magnus.westerlund@ericsson.com
Cotton, et al. Expires November 27, 2010 [Page 30]
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Stuart Cheshire
Apple Inc.
1 Infinite Loop
Cupertino, CA 95014
USA
Phone: +1 408 974 3207
Email: cheshire@apple.com
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