draft-ietf-grow-embed-addr-00.txt   draft-ietf-grow-embed-addr-01.txt 
Global Routing Operations D. Plonka Global Routing Operations D. Plonka
Internet-Draft University of Wisconsin Internet-Draft University of Wisconsin
Expires: May 1, 2004 November 2003 Expires: December 6, 2004 June 7, 2004
Embedding Globally Routable Internet Addresses Considered Harmful Embedding Globally Routable Internet Addresses Considered Harmful
draft-ietf-grow-embed-addr-00 draft-ietf-grow-embed-addr-01
Status of this Memo Status of this Memo
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that other Task Force (IETF), its areas, and its working groups. Note that
groups may also distribute working documents as Internet-Drafts. other groups may also distribute working documents as
Internet-Drafts.
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."
The list of current Internet-Drafts can be accessed at http:// The list of current Internet-Drafts can be accessed at
www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on May 1, 2004. This Internet-Draft will expire on December 6, 2004.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2003). All Rights Reserved. Copyright (C) The Internet Society (2004). All Rights Reserved.
Abstract Abstract
Vendors of consumer electronics and network gear have produced and
sold hundreds of thousands of Internet hosts with globally routable
Internet Protocol addresses embedded within their products' firmware.
These products are now in operation world-wide and primarily include,
but are not necessarily limited to, low-cost routers and middleboxes
for personal or residential use.
This "hard-coding" of globally routable IP addresses as identifiers
within the host's firmware presents significant problems to the
operation of the Internet and to the management of its address space.
This document means to clarify best current practices in the Internet This document means to clarify best current practices in the Internet
community. It denouces the practice of embedding references to community. Internet hosts should not contain globally routable
unique, globally routable IP addresses in Internet hosts, describes Internet Protocol addresses embedded within firmware or elsewhere as
some of the resulting problems, and considers selected alternatives. part of their default configuration such that it influences run-time
It is also intended to remind the Internet community of the ephemeral behavior.
nature of unique, globally routable IP addresses and that the
assignment and use of IP addresses as identifiers is temporary and
therefore should not be used in fixed configurations.
Revision History Revision History
The following is the revision history of this document since "-00": RFC-EDITOR: PLEASE REMOVE REVISION HISTORY BEFORE PUBLICATION. The
following is the revision history of this document
$Log: draft-ietf-grow-embed-addr.xml,v $ $Log: draft-ietf-grow-embed-addr.xml,v $
Revision 1.14 2004/06/07 18:16:27 plonka
split references into normative and informative sections
Revision 1.13 2004/06/07 16:32:10 plonka
Set category to BCP.
Rewrote/resized abstract and introduction as suggested by Pekka Savola.
Improved section about using DNS names, re; hard-coding caveats, as
suggested by Pekka Savola.
Encouraged use of IPv4 documentation/example prefix 192.0.2.0/24 rather
than private addresses, as noted by Pekka Savola.
Mentioned IPv6 2001:DB8::/32 documentation prefix, as noted by Tom Petch.
Added note for RFC-editor requesting that revision history be removed.
Reworded various portions.
Renamed from "-00" to "-01" and updated date.
Revision 1.12 2003/12/05 15:51:23 plonka
typo fixes and updates from Michael Patton
Revision 1.11 2003/12/02 22:28:04 plonka Revision 1.11 2003/12/02 22:28:04 plonka
renamed from draft-plonka-embed-addr to draft-ietf-grow-embed-addr renamed from draft-plonka-embed-addr to draft-ietf-grow-embed-addr
integrated suggestions from Paul Barford integrated suggestions from Paul Barford
reordered references to match the text reordered references to match the text
added quote from RFC2101 re: use of IPv4 addresses as identifiers added quote from RFC2101 re: use of IPv4 addresses as identifiers
as mentioned by Brian Carpenter as mentioned by Brian Carpenter
skipping to change at page 4, line 7 skipping to change at page 4, line 7
- indicated that DNS server(s) should be configurable - indicated that DNS server(s) should be configurable
- clarified DNS round-robin behavior - clarified DNS round-robin behavior
- clarified "unsolicited traffic" by saying "IP traffic" - clarified "unsolicited traffic" by saying "IP traffic"
added revision history and appendix A added revision history and appendix A
Figure 1 Figure 1
1. Introduction 1. Introduction
Internet hosts should not contain globally routable Internet Protocol Vendors of consumer electronics and network gear have produced and
addresses embedded within firmware or elsewhere as part of their sold hundreds of thousands of Internet hosts with globally routable
default configuration influencing their run-time behavior. Internet Protocol addresses embedded within their products' firmware.
These products are now in operation world-wide and primarily include,
but are not necessarily limited to, low-cost routers and middleboxes
for personal or residential use.
This "hard-coding" of globally routable IP addresses as identifiers
within the host's firmware presents significant problems to the
operation of the Internet and to the management of its address space.
Ostensibly, this practice arose as an attempt to simplify Ostensibly, this practice arose as an attempt to simplify
configuration of IP hosts by preloading them with IP addresses as configuration of IP hosts by preloading them with IP addresses as
service identifiers. Unfortunately, products that rely on such service identifiers. Unfortunately, products that rely on such
embedded IP addresses initially may appear convenient to both the embedded IP addresses initially may appear convenient to both the
product's designer and its operator or user, but this dubious benefit product's designer and its operator or user, but this dubious benefit
comes at the expense of others in the Internet community. comes at the expense of others in the Internet community.
This document denounces the practice of embedding references to
unique, globally routable IP addresses in Internet hosts, describes
some of the resulting problems, and considers selected alternatives.
It also reminds the Internet community of the ephemeral nature of
unique, globally routable IP addresses and that the assignment and
use of IP addresses as identifiers is temporary and therefore should
not be used in fixed configurations.
2. Problems 2. Problems
In a number cases, the embedding of IP addresses has caused Internet In a number cases, the embedding of IP addresses has caused Internet
products to rely on a single central Internet service. This can products to rely on a single central Internet service. This can
result in a service outage when the aggregate workload overwhelms result in a service outage when the aggregate workload overwhelms
that service. When fixed addresses are embedded in an that service. When fixed addresses are embedded in an
ever-increasing number of client IP hosts, this practice runs ever-increasing number of client IP hosts, this practice runs
directly counter to the design intent of hierarchically deployed directly counter to the design intent of hierarchically deployed
services that would otherwise be robust solutions. services that would otherwise be robust solutions.
The reliability, scalability, and performance of many Internet The reliability, scalability, and performance of many Internet
services require that the pool of users not directly access a service services require that the pool of users not directly access a service
by IP address. Instead they rely on a level of indirection provided by IP address. Instead they typically rely on a level of indirection
by the Domain Name System, RFC 2219 [1]. DNS permits the service provided by the Domain Name System, RFC 2219 [6]. DNS permits the
operator to reconfigure the resources for maintenance and service operator to reconfigure the resources for maintenance and to
load-balancing without the participation of the users. For instance, load-balance without the participation of the users. For instance,
one common load-balancing technique employs multiple DNS records with one common load-balancing technique employs multiple DNS records with
the same name that are then rotated in a round-robin fashion in the the same name that are then rotated in a round-robin fashion in the
set of answers returned by the Berkeley Internet Name Daemon (BIND) set of answers returned by many DNS server implementations. Upon
and other DNS server implementations. Upon receiving such as receiving such a response to a query, resolvers typically will try
response to a query, resolvers typically use the first valid answer the answers in order, until one succeeds, thus enabling the operator
in the set, thus enabling the operator to distribute the user request to distribute the user request load across a set of servers with
load across a set of servers with discrete IP addresses that discrete IP addresses that generally remain unknown to the user.
generally remain unknown to the user.
Embedding globally unique IP addresses taints the IP address blocks Embedding globally unique IP addresses taints the IP address blocks
in which they reside, lessening the usefulness and portability of in which they reside, lessening the usefulness and portability of
those IP address blocks and increasing the cost of operation. those IP address blocks and increasing the cost of operation.
Unsolicited traffic may continue to be delivered to the embedded Unsolicited traffic may continue to be delivered to the embedded
addresses, even after the IP address or block has been reassigned and addresses well after the IP address or block has been reassigned and
no longer hosts the service for which that traffic was meant. Circa no longer hosts the service for which that traffic was intended.
1997, the authors of RFC 2101 [3] made this observation: Circa 1997, the authors of RFC 2101 [5] made this observation:
Due to dynamic address allocation and increasingly frequent Due to dynamic address allocation and increasingly frequent
network renumbering, temporal uniqueness of IPv4 addresses is no network renumbering, temporal uniqueness of IPv4 addresses is no
longer globally guaranteed, which puts their use as identifiers longer globally guaranteed, which puts their use as identifiers
into severe question. into severe question.
When IP addresses are used as service identifiers in the
In this way, IP address blocks containing addresses that have been configuration of many Internet hosts, the IP address blocks become
embedded into the configuration of many Internet hosts become
encumbered by their historical use. This may interfere with the encumbered by their historical use. This may interfere with the
ability of the Internet Assigned Numbers Authority (IANA) and the ability of the Internet Assigned Numbers Authority (IANA) and the
Internet Registry (IR) hierarchy to usefully reallocate IP address Internet Registry (IR) hierarchy to usefully reallocate IP address
blocks. This is of particular concern as the IPv4 address space nears blocks. Likewise, to facilitate IP address reuse, RFC 2050 [1],
exhaustion. Note that, to facilitate IP address reuse, RFC 2050 [2],
encourages Internet Service Providers (ISPs) to treat address encourages Internet Service Providers (ISPs) to treat address
assignments as "loans". assignments as "loans".
Because consumers are not necessarily capable, experienced operators Because consumers are not necessarily experienced in the operation of
of Internet hosts, they are not able to be relied upon to implement a Internet hosts, they are not able to be relied upon to implement a
fix if and when problems arise. As such, a significant fix if and when problems arise. As such, a significant
responsibility lies with the manufacturer or vendor of the Internet responsibility lies with the manufacturer or vendor of the Internet
host to avoid embedding IP addresses. host to avoid embedding IP addresses in ways which cause the
aforementioned problems.
3. Recommendations 3. Recommendations
Internet host and router designers, including network product Internet host and router designers, including network product
manufacturers, should not assume that their products will only be manufacturers, should not assume that their products will be deployed
deployed on a single global Internet, that they happen to observe and used in only a single global Internet, that they happen to
today. A myriad of private internets in which these products will be observe today. A myriad of private or future internets in which
used will often not allow these hosts to establish end-to-end these products will be used may not allow those hosts to establish
communications with arbitrary hosts on the global Internet. end-to-end communications with arbitrary hosts on the global
Internet. Since the product failure modes resulting from unknown
future states cannot be fully explored, one should avoid assumptions
regarding the longevity of our current Internet.
Vendors should, by default, disable unnecessary features in their Vendors should, by default, disable unnecessary features in their
products. This is especially true of features that generate products. This is especially true of features that generate
unsolicited IP traffic. In this way these hosts will be conservative unsolicited IP traffic. In this way these hosts will be conservative
regarding the unsolicited Internet traffic they produce. For regarding the unsolicited Internet traffic they produce. For
instance, one of the most common uses of embedded IP addresses has instance, one of the most common uses of embedded IP addresses has
been the hard-coding of addresses of well know public Simple Network been the hard-coding of addresses of well know public Simple Network
Time Protocol (SNTP RFC 2030 [4]) servers, even though only a small Time Protocol (SNTP RFC 2030 [7]) servers, even though only a small
fraction of the users benefits from these products even having some fraction of the users benefits from these products even having some
notion of the current date and time. notion of the current date and time.
Vendors should provide an operator interface for every feature that Vendors should provide an operator interface for every feature that
generates unsolicited IP traffic. A prime example of this that the generates unsolicited IP traffic. A prime example of this is that
Domain Name System resolver should have an interface enabling the the Domain Name System resolver should have an interface enabling the
operator to either explicitl set the servers of his choosing or to operator to either explicitly set the servers of his choosing or to
enable the use of a standard automated configuration protocol such as enable the use of a standard automated configuration protocol such as
DHCP, defined by RFC 2132 [5]. Within the operator interface, these DHCP, defined by RFC 2132 [8]. Within the operator interface, these
features should be disabled by default so that one consequence of features should originally be disabled so that one consequence of
enabling these features is that the operator becomes aware that the subsequently enabling these features is that the operator becomes
feature exists. This will mean that it is more likely that the aware that the feature exists. This will mean that it is more likely
product's owner or operator can participate in problem determination that the product's owner or operator can participate in problem
and mitigation when problems arise. determination and mitigation when problems arise.
Internet hosts should use the Domain Name System to determine the Internet hosts should use the Domain Name System to determine the IP
routable IP addresses associated with the Internet services they addresses associated with the Internet services they require.
require. However, note that simply hard-coding DNS names rather than However, simply hard-coding DNS names rather than IP addresses is not
IP addresses is not a panacea. Entries in the domain name space are a panacea. Entries in the domain name space are also ephemeral and
also ephemeral and can change owners for various reasons including can change owners for various reasons including acquisitions and
such as acquisitions and litigation. A given vendor ought not assume litigation. A given vendor ought not assume that anyone will retain
that it will retain control of a given zone indefinitely. control of a given zone indefinitely. RFC 2606 [2] defines the
IANA-reserved "example.com", "example.net", and "example.org" domains
for use in example configurations and documentation.
Whenever possible, default configurations, documentation, and example Default configurations, documentation, and example configurations for
configurations for Internet hosts should use Private Internet Internet hosts should use Internet addresses that reside with special
Addresses, as defined by RFC 1918 [6], rather than unique, globally blocks that have been reserved for these purposes, rather than
routable IP addresses. unique, globally routable IP addresses. For IPv4, RFC 3330 [3]
states that the 192.0.2.0/24 block has been assigned for use in
documentation and example code. The IPv6 global unicast address
prefix 2001:DB8::/32 has been similarly reserved for documentation
purposes. Private Internet Addresses, as defined by RFC 1918 [4],
should not be used for such purposes.
Service providers and enterprise network operators should advertise Service providers and enterprise network operators should advertise
the identities of suitable local services. For instance, the DHCP the identities of suitable local services. For instance, the DHCP
protocol, as defined by RFC 2132 [5], enables one to configure a protocol, as defined by RFC 2132 [8], enables one to configure a
server to answer queries regarding available servers to clients that server to answer queries for service identitifiers to clients that
ask for them. Unless the advertisement of local services is ask for them. When local services are available but not pervasively
ubiquitous, designers may resort to ad hoc mechanisms that rely on advertised using such common protocols, designers are more likely
deploy ad hoc initialization mechanisms that unnecessarily rely on
central services. central services.
Operators that provide public services on the global Internet, such Operators that provide public services on the global Internet, such
as the NTP community, should deprecate the explicit advertisement of as the NTP community, should deprecate the explicit advertisement of
IP addresses of public services. These addresses are ephemeral. As the IP addresses of public services. These addresses are ephemeral.
such, their widespread citations in public service indexes interferes As such, their widespread citation in public service indexes
with the ability to reconfigure the service as necessary to address interferes with the ability to reconfigure the service as necessary
unexpected, increased workloads. to address unexpected, increased traffic.
4. Security Considerations 4. Security Considerations
Embedding or "hard-coding" IP addresses within a host's configuration Embedding or "hard-coding" IP addresses within a host's configuration
almost always means that some sort of host-based trust model is being often means that a host-based trust model is being employed, and that
employed, and that the Internet host with the given address is the Internet host with the given address is trusted in some way. Due
trusted in some way. Due to the ephemeral roles of routable IP to the ephemeral roles of routable IP addresses, the practice of
addresses, the practice of embedding them within products' firmware embedding them within products' firmware or default configurations
or default configurations presents a security risk. presents a security risk in that unknown parties may inadvertently be
trusted.
An Internet host designer may be tempted to implement some sort of Internet host designers may be tempted to implement some sort of
remote control mechanism within a product, by which its Internet host remote control mechanism within a product, by which its Internet host
configuration can be changed without reliance on, interaction with, configuration can be changed without reliance on, interaction with,
or even the knowledge of its operator or user. This raises security or even the knowledge of its operator or user. This raises security
issues of its own. If such a scheme is implemented, this should be issues of its own. If such a scheme is implemented, this should be
fully disclosed to the customer, operator, and user so that an fully disclosed to the customer, operator, and user so that an
informed decision can be made, in accordance with local security or informed decisions can be made, perhaps in accordance with local
privacy policy. Furthermore, the significant possibility of security or privacy policy. Furthermore, the significant possibility
malicious parties exploiting such a remote control mechanism may of malicious parties exploiting such a remote control mechanism may
completely negate any potential benefit of the remote control scheme. completely negate any potential benefit of the remote control scheme.
5. Conclusion 5. IANA Considerations
As larger numbers of homogenous hosts continue to be deployed, it is This document creates no new requirements on IANA namespaces.
particularly important that both their designers and other members of
the Internet community are diligent in assessing host implementation 6. Conclusion
quality and reconfigurability. Unique, globally routable IP
addresses should not be embedded within a host's fixed configuration As larger numbers of homogenous Internet hosts continue to be
because doing so excludes the ability to remotely influence hosts deployed, it is particularly important that both their designers and
when the unsolicited IP traffic they generate causes problems for the other members of the Internet community diligently assess host
for those operating the IP addresses to which the traffic is implementation quality and reconfigurability. Unique, globally
routable IP addresses should not be embedded within a host's fixed
configuration because doing so excludes the ability to remotely
influence hosts when the unsolicited IP traffic they generate causes
problems for those operating the IP addresses to which the traffic is
destined. destined.
6. Acknowledgements 7. Acknowledgements
Thanks go to the following folks for providing input during the The author thanks the following reviewers for their contributions to
preparation of this document: Paul Barford and Mike O'Connor. this document: Paul Barford, Mike O'Connor, Michael Patton, Tom
Petch, Pekka Savola, and David Meyer.
References 8. References
[1] Hamilton, M., "Use of DNS Aliases for Network Services", RFC 8.1 Normative References
2219, BCP 17, October 1997.
[2] Hubbard, K., "INTERNET REGISTRY IP ALLOCATION GUIDELINES", RFC [1] Hubbard, K., "INTERNET REGISTRY IP ALLOCATION GUIDELINES", RFC
2050, BCP 12, November 1996. 2050, BCP 12, November 1996.
[3] Carpenter, B., "IPv4 Address Behaviour Today", RFC 2101, [2] Eastlake, D., "Reserved Top Level DNS Names", RFC 2606, BCP 32,
June 1999.
[3] Internet Assigned Numbers Authority, "Special-Use IPv4
Addresses", RFC 3330, September 2002.
[4] Rekhter, Y., "Address Allocation for Private Internets", RFC
1918, BCP 5, February 1996.
8.2 Informative References
[5] Carpenter, B., "IPv4 Address Behaviour Today", RFC 2101,
February 1997. February 1997.
[4] Mills, D., "Simple Network Time Protocol (SNTP) Version 4 for [6] Hamilton, M., "Use of DNS Aliases for Network Services", RFC
2219, BCP 17, October 1997.
[7] Mills, D., "Simple Network Time Protocol (SNTP) Version 4 for
IPv4, IPv6 and OSI", RFC 2030, October 1996. IPv4, IPv6 and OSI", RFC 2030, October 1996.
[5] Alexander, S., "DHCP Options and BOOTP Vendor Extensions", RFC [8] Alexander, S., "DHCP Options and BOOTP Vendor Extensions", RFC
2132, March 1997. 2132, March 1997.
[6] Rekhter, Y., "Address Allocation for Private Internets", RFC
1918, BCP 5, February 1996.
Author's Address Author's Address
David J. Plonka David J. Plonka
University of Wisconsin - Madison University of Wisconsin - Madison
DoIT, room b116
1210 W. Dayton Street
Madison, WI 53705
US
Phone: +1 608 265 5184 EMail: plonka AT doit DOT wisc DOT edu
EMail: plonka@doit.wisc.edu
URI: http://net.doit.wisc.edu/~plonka/ URI: http://net.doit.wisc.edu/~plonka/
Appendix A. Background Appendix A. Background
In June 2003, the University of Wisconsin discovered that the network In June 2003, the University of Wisconsin discovered that a network
product vendor named NetGear had manufactured and shipped over product vendor named NetGear had manufactured and shipped over
700,000 routers with firmware containing a hard-coded reference to 700,000 routers with firmware containing a hard-coded reference to
the IP address of one of the University's NTP servers: the IP address of one of the University's NTP servers:
128.105.39.11, which was also known as "ntp1.cs.wisc.edu", a public 128.105.39.11, which was also known as "ntp1.cs.wisc.edu", a public
stratum-2 NTP server. stratum-2 NTP server.
Due to that embedded fixed configuration and a bug in the Due to that embedded fixed configuration and an unrelated bug in the
implementation, the NetGear SNTP client has a failure mode in which SNMP client, the affected products occasionally exhibit a failure
each flawed router produces one query per second destined for the IP mode in which each flawed router produces one query per second
address 128.105.39.11, and hence produces a large-scale flood of destined for the IP address 128.105.39.11, and hence produces a
Internet traffic from hundreds-of-thousands of legitimate source large-scale flood of Internet traffic from hundreds-of-thousands of
addresses and destined for the University's network resulting in source addresses, destined for the University's network, resulting in
significant operational problems. significant operational problems.
These flawed routers are widely deployed throughout the global These flawed routers are widely deployed throughout the global
Internet and are likely to remain in use for years to come. As such, Internet and are likely to remain in use for years to come. As such,
the University of Wisconsin with the cooperation of NetGear will the University of Wisconsin with the cooperation of NetGear will
build a new anycast time service which aims to mitigate the damage build a new anycast time service which aims to mitigate the damage
caused by the misbehavior of these flawed routers. caused by the misbehavior of these flawed routers.
A technical report regarding the details of this situation is A technical report regarding the details of this situation is
available on the world-wide-web: Flawed Routers Flood University of available on the world wide web:
Wisconsin Internet Time Server [7] <http://www.cs.wisc.edu/~plonka/netgear-sntp/>
Intellectual Property Statement Intellectual Property Statement
The IETF takes no position regarding the validity or scope of any The IETF takes no position regarding the validity or scope of any
intellectual property or other rights that might be claimed to intellectual property or other rights that might be claimed to
pertain to the implementation or use of the technology described in pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights this document or the extent to which any license under such rights
might or might not be available; neither does it represent that it might or might not be available; neither does it represent that it
has made any effort to identify any such rights. Information on the has made any effort to identify any such rights. Information on the
IETF's procedures with respect to rights in standards-track and IETF's procedures with respect to rights in standards-track and
skipping to change at page 14, line 29 skipping to change at page 15, line 29
be obtained from the IETF Secretariat. be obtained from the IETF Secretariat.
The IETF invites any interested party to bring to its attention any The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary copyrights, patents or patent applications, or other proprietary
rights which may cover technology that may be required to practice rights which may cover technology that may be required to practice
this standard. Please address the information to the IETF Executive this standard. Please address the information to the IETF Executive
Director. Director.
Full Copyright Statement Full Copyright Statement
Copyright (C) The Internet Society (2003). All Rights Reserved. Copyright (C) The Internet Society (2004). All Rights Reserved.
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
and distributed, in whole or in part, without restriction of any and distributed, in whole or in part, without restriction of any
kind, provided that the above copyright notice and this paragraph are kind, provided that the above copyright notice and this paragraph are
included on all such copies and derivative works. However, this included on all such copies and derivative works. However, this
document itself may not be modified in any way, such as by removing document itself may not be modified in any way, such as by removing
the copyright notice or references to the Internet Society or other the copyright notice or references to the Internet Society or other
Internet organizations, except as needed for the purpose of Internet organizations, except as needed for the purpose of
 End of changes. 

This html diff was produced by rfcdiff 1.23, available from http://www.levkowetz.com/ietf/tools/rfcdiff/