draft-ietf-dhc-dhcpv6-opt-netboot-04.txt   draft-ietf-dhc-dhcpv6-opt-netboot-05.txt 
DHC T. Huth DHC T. Huth
Internet-Draft J. Freimann Internet-Draft J. Freimann
Intended status: Standards Track IBM Germany Research & Intended status: Standards Track IBM Germany Research &
Expires: October 16, 2009 Development GmbH Expires: February 11, 2010 Development GmbH
V. Zimmer V. Zimmer
Intel Intel
D. Thaler D. Thaler
Microsoft Microsoft
April 14, 2009 August 10, 2009
DHCPv6 option for network boot DHCPv6 option for network boot
draft-ietf-dhc-dhcpv6-opt-netboot-04 draft-ietf-dhc-dhcpv6-opt-netboot-05
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
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http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
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This Internet-Draft will expire on October 16, 2009. This Internet-Draft will expire on February 11, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info). publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
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required for booting a node from the network. required for booting a node from the network.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Options . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Options . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Boot File Uniform Resource Locator (URL) Option . . . . . 4 3.1. Boot File Uniform Resource Locator (URL) Option . . . . . 4
3.2. Boot File Parameters Option . . . . . . . . . . . . . . . 5 3.2. Boot File Parameters Option . . . . . . . . . . . . . . . 5
3.3. Client System Architecture Type Option . . . . . . . . . . 6 3.3. Client System Architecture Type Option . . . . . . . . . . 6
3.4. Client Network Interface Identifier Option . . . . . . . . 6 3.4. Client Network Interface Identifier Option . . . . . . . . 7
4. Appearance of the options . . . . . . . . . . . . . . . . . . 7 4. Appearance of the options . . . . . . . . . . . . . . . . . . 8
5. Download protocol considerations . . . . . . . . . . . . . . . 7 5. Download protocol considerations . . . . . . . . . . . . . . . 8
6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 8 6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 8
7. Security considerations . . . . . . . . . . . . . . . . . . . 9 7. Security considerations . . . . . . . . . . . . . . . . . . . 9
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 9 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10
9.1. Normative References . . . . . . . . . . . . . . . . . . . 9 9.1. Normative References . . . . . . . . . . . . . . . . . . . 10
9.2. Informative References . . . . . . . . . . . . . . . . . . 10 9.2. Informative References . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction 1. Introduction
Network booting means that a node which should be booted fetches the This draft describes DHCPv6 options that can be used to provide
files required for booting via its network device from a server. configuration information for a node that must be booted using the
Network booting is, for example, very useful in environments where network, rather than from local storage.
the administrators have to maintain a large number of nodes. Since
all boot and configuration files are stored on a central server, the Network booting is used, for example, in some environments where
maintenance of all nodes can be kept simple this way. administrators have to maintain a large number of nodes. By serving
all boot and configuration files from central server, the effort
required to maintain these nodes is greatly reduced.
A typical boot file would be, for example, an operating system kernel A typical boot file would be, for example, an operating system kernel
or a boot loader program. To be able to execute such a file, the or a boot loader program. To be able to execute such a file, the
firmware (BIOS) running on the client node must perform the following firmware (BIOS) running on the client node must perform the following
two steps (see Figure 1): First get all information which are two steps (see Figure 1): First get all information which is required
required for downloading and executing the boot file such as: the for downloading and executing the boot file. Second, download the
server on which the boot files can be found, the protocol to be used boot file and execute it.
for the download (for example HTTP [RFC2616] or TFTP [RFC1350]), the
name of the boot file and additional parameters which should be
passed to the OS kernel or boot loader program respectively. As
second step, download the boot file from the file server and execute
it.
+------+ +------+
_______________________\| DHCP | _______________________\| DHCP |
/ 1 Get boot file info /|Server| / 1 Get boot file info /|Server|
+------+ +------+ +------+ +------+
| Host | | Host |
+------+ +------+ +------+ +------+
\_______________________\| File | \_______________________\| File |
2 Download boot file /|Server| 2 Download boot file /|Server|
+------+ +------+
Figure 1: Network Boot Sequence Figure 1: Network Boot Sequence
Information that is required for booting over the network can include
information about the server on which the boot files can be found,
the protocol to be used for the download (for example HTTP [RFC2616]
or TFTP [RFC1350]), the name of the boot file and additional
parameters which should be passed to the OS kernel or boot loader
program respectively.
DHCPv6 allows client nodes to ask a DHCPv6 server for configuration DHCPv6 allows client nodes to ask a DHCPv6 server for configuration
parameters. Contrary to its IPv4 predecessor, DHCPv6 does not yet parameters. This document provides new options which a client can
define a way to query network boot options such as the IPv6 address request from the DHCPv6 server to satisfy its requirements for
of a boot file server and boot file names. Therefore this document booting.
defines new DHCPv6 options which are required for network booting
clients.
2. Conventions 2. Conventions
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Terminology specific to IPv6 and DHCPv6 are used in the same way as Terminology specific to IPv6 and DHCPv6 are used in the same way as
defined in the "Terminology" sections of RFC 3315 [RFC3315]. defined in the "Terminology" sections of RFC 3315 [RFC3315].
3. Options 3. Options
As specified in the DHCPv6 RFC [RFC3315], all values in the options Option formats comply with DHCPv6 options per [RFC3315] (section 6).
are in network byte order. Options are byte-aligned but are not
aligned in any other way such as on 2 or 4 byte boundaries. There is
no padding between the options.
3.1. Boot File Uniform Resource Locator (URL) Option 3.1. Boot File Uniform Resource Locator (URL) Option
This option consists of an ASCII string. It is used to convey an URL This option consists of an US-ASCII string. It is used to convey an
to a boot file. URL to a boot file.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPT_BOOTFILE_URL | option-len | | OPT_BOOTFILE_URL | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . | precedence | bootfile-url |
. bootfile-url (variable length) . +-+-+-+-+-+-+-+-+ (variable length) .
. . . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Format description: Format description:
option-code OPT_BOOTFILE_URL (TBD1). option-code OPT_BOOTFILE_URL (TBD1).
option-len Length of the bootfile URL option in octets (not option-len Length of the bootfile URL option in octets (not
including the size of the option-code and option- including the size of the option-code and option-
len fields). len fields).
bootfile-url This ASCII string is the URL (conforming to precedence A single unsigned octet indicating the order in
[RFC3986]) for a boot file. This string starts which this URL should be processed, if more than
with the protocol which is used for downloading. one URL appears in the message.
Separated by "://", the hostname or IPv6 address of
the server hosting the boot file follows, and then
the path, file name and query parts of the URL.
The string is not null-terminated.
Note about the bootfile-url: This string can either contain a bootfile-url This US-ASCII string is the URL for the boot file,
hostname or a literal IPv6 address to specify the server where the as defined in [RFC3986]. The string is not NUL-
boot file should be downloaded from. All clients which implement the terminated.
OPT_BOOTFILE_URL option MUST be able to handle IPv6 addresses here
and SHOULD also be able to handle a hostname in the URL. The IPv6 The node identifier in the URL must be reachable using IPv6. If the
URL is expressed using an IPv6 address rather than a domain name, the
address in the URL then MUST be enclosed in "[" and "]" characters, address in the URL then MUST be enclosed in "[" and "]" characters,
conforming to [RFC3986]. Clients SHOULD also be able to handle conforming to [RFC3986]. Clients that have DNS implementations
hostnames in the URLs. However, in this case the firmware should support the use of domain names in the URL.
implementation on the client machine must support DNS, too. Due to
size limitations, this might not be possible in all firmware
implementations, so support for hostnames in the URLs is only
optional.
Multiple occurrences of OPT_BOOTFILE_URL can be present in a single Multiple occurrences of OPT_BOOTFILE_URL MAY be present in a single
DHCP message. Clients MUST process them in the order in which they DHCP message. Clients MUST process them according to the value of
appear within the message. The client starts with the first file the precedence field - the lowest precedence should be processed
that should be downloaded and executed. In case of a failure the first. If this fails, then the second-lowest should be used, and so
process should continue with the second one and so on. on.
Servers SHOULD NOT send two Bootfile URL options with the same
precedence. Clients receiving more than one OPT_BOOTFILE_URL option
with the same precedence SHOULD discard any extra such options. The
order in which the client processes options is not specified, and
therefore server implementations cannot assume that the client will
discard a particular such option.
The value of the precedence field MUST NOT be zero.
3.2. Boot File Parameters Option 3.2. Boot File Parameters Option
This option consists of multiple ASCII strings. They are used to This option consists of multiple US-ASCII strings. They are used to
specify parameters for the boot file (e.g. parameters for the kernel specify parameters for the boot file (e.g. parameters for the kernel
or boot loader program). or boot loader program).
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPT_BOOTFILE_PARAM | option-len | | OPT_BOOTFILE_PARAM | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| param-len 1 | parameter 1 | | precedence | param-len 1 | parameter 1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (variable length) . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (variable .
. | . length) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. . . .
. <multiple Parameters> . . <multiple Parameters> .
. . . .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| param-len n | parameter n | | param-len n | parameter n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (variable length) . +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ (variable length) .
. | . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Format description: Format description:
option-code OPT_BOOTFILE_PARAM (TBD2). option-code OPT_BOOTFILE_PARAM (TBD2).
option-len Length of the bootfile parameters option in octets option-len Length of the bootfile parameters option in octets
(not including the size of the option-code and (not including the size of the option-code and
option-len fields). option-len fields).
precedence A one-octet quantity indicating the bootfile-url
option to which this set of parameters applies.
param-len 1...n This is a 16-bit integer which specifies the length param-len 1...n This is a 16-bit integer which specifies the length
of the following parameter in octets (not including of the following parameter in octets (not including
the parameter-length field). the parameter-length field).
parameters 1...n These ASCII strings are parameters needed for parameters 1...n These US-ASCII strings are parameters needed for
booting, e.g. kernel parameters. The strings are booting, e.g. kernel parameters. The strings are
not null-terminated. not NUL-terminated.
The firmware MUST pass these parameters in the order they appear in The firmware MUST pass these parameters in the order they appear in
the OPT_BOOTFILE_PARAM option to the boot file which has been the OPT_BOOTFILE_PARAM option to the boot file which has been
specified in the OPT_BOOTFILE_URL option. specified in the OPT_BOOTFILE_URL option.
Multiple occurrences of OPT_BOOTFILE_PARAM MAY be present in a single
DHCP message. Clients MUST process them according to the value of
the precedence field:
o If the precedence field of the Bootfile Parameters option is zero,
the client SHOULD provide these parameters when it attempts to
execute any Bootfile it has loaded using any of the provided
Bootfile URL options.
o If the precedence field of the Bootfile Parameters option is
nonzero, the client SHOULD provide these parameters only when it
attempts to execute a Bootfile it loaded using a Bootfile URL
option with a precedence field that has the same value.
o In the event that the client receives both a Bootfile Parameters
option with a precedence field of zero and one with a precedence
field that matches a certain Bootfile URL option, the client MUST
use the Bootfile Parameters option whose predence matches the
precedence of the Bootfile URL option.
3.3. Client System Architecture Type Option 3.3. Client System Architecture Type Option
This option provides parity with the Client System Architecture Type This option provides parity with the Client System Architecture Type
Option defined for DHCPv4 in [RFC4578] section 2.1. Option defined for DHCPv4 in [RFC4578] section 2.1.
The format of the option is: The format of the option is:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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These options MUST NOT appear in DHCPv6 messages other than the types These options MUST NOT appear in DHCPv6 messages other than the types
Solicit, Advertise, Request, Renew, Rebind, Information-Request and Solicit, Advertise, Request, Renew, Rebind, Information-Request and
Reply. Reply.
The option-codes of these options MAY appear in the Option Request The option-codes of these options MAY appear in the Option Request
Option in the DHCPv6 message types Solicit, Request, Renew, Rebind, Option in the DHCPv6 message types Solicit, Request, Renew, Rebind,
Information-Request and Reconfigure. Information-Request and Reconfigure.
5. Download protocol considerations 5. Download protocol considerations
Depending on the network infrastructure, various special requirements The Bootfile URL option does not place any constraints on the
could be imposed on the download protocol, so this document does not protocol used for downloading the Bootfile, other than that it must
force one protocol for all scenarios. However, in case there there be possible to specify it in a URL. For the sake of administrative
are no special requirements, the HTTP protocol SHOULD be used as simplicity, we strongly recommend that, at a mininum, implementors of
download protocol. network boot loaders implement the well-known and established
hypertext transfer protocol (HTTP, see [RFC2616]) for downloading.
RFC 906 [RFC906] suggested to use TFTP for bootstrap loading. Since Please note that for IPv6, this supersedes [RFC906] which recommended
TFTP is based on UDP, it has the advantage that it can also be used to use TFTP for downloading (see [RFC3617] for TFTP URL definition).
in firmware implementations which have to deal with size and
complexity constraints and thus can not include a full-blown TCP/IP
stack. It can also be used in multicast mode (see [RFC2090]) which
is useful when a lot of nodes boot the same boot file at the same
time. So if TFTP should be used as download protocol, the boot file
URLs then must be specified according to RFC 3617 [RFC3617].
However, TFTP also has some severe limitations, for example
performance limitations due to acknowledging each packet and size
limitations due to using only 16-bit packet counters. So this
specification suggests to use now the well-known and established
hypertext transfer protocol (HTTP, see [RFC2616]) as default for
network booting instead. If a secure download is required, it is
also possible to use HTTP with TLS (HTTPS, see [RFC2818]).
An alternative approach to network booting is to bootstrap the system
with iSCSI. In this case, the URL in the OPT_BOOTFILE_URL option
MUST be specified according to the "iscsi:" string definition in
chapter 5 of [RFC4173]. Note that [RFC4173] also suggests that the
"iscsi:" string should be specified in the so-called "Root Path"
option. However, this option does not exist for DHCPv6 yet, and with
the OPT_BOOTFILE_URL it is also not necessary anymore. So for IPv6
iSCSI booting, the "iscsi:" string MUST be specified as URL in the
OPT_BOOTFILE_URL option instead.
If multiple interfaces are available for booting, it might be a good When using iSCSI for booting, the "iscsi:"-URI is formed as defined
strategy to send out requests on each interface in parallel to speed in [RFC4173]. The functionality attributed in RFC4173 to a root path
up the discovery. However how to handle multiple replies, i.e. option is provided for IPv6 by the bootfile URL option instead.
replies from more than one DHCP server is not a problem that can be
easily solved on the protocol level. It is up to the implementors to
provide users with a possibility to either choose a network interface
to boot from, or to assign a preference to interfaces or even known
DHCP servers.
6. IANA considerations 6. IANA considerations
The following options need to be assigned by the IANA from the option The following options need to be assigned by the IANA from the option
number space defined in the chapter 22 of the DHCPv6 RFC [RFC3315]. number space defined in the chapter 22 of the DHCPv6 RFC [RFC3315].
+-------------------------+-------+--------------+ +-------------------------+-------+--------------+
| Option name | Value | Specified in | | Option name | Value | Specified in |
+-------------------------+-------+--------------+ +-------------------------+-------+--------------+
| OPT_BOOTFILE_URL | TBD1 | Section 3.1 | | OPT_BOOTFILE_URL | TBD1 | Section 3.1 |
skipping to change at page 9, line 13 skipping to change at page 9, line 16
Architecture Type". Registry entries consist of a 16-bit integer Architecture Type". Registry entries consist of a 16-bit integer
recorded in decimal format, and a descriptive name. The initial recorded in decimal format, and a descriptive name. The initial
values of this registry can be found in [RFC4578] section 2.1. values of this registry can be found in [RFC4578] section 2.1.
The assignment policy for values shall be Expert Review (see The assignment policy for values shall be Expert Review (see
[RFC5226]), and any requests for values must supply the descriptive [RFC5226]), and any requests for values must supply the descriptive
name for the processor architecture type. name for the processor architecture type.
7. Security considerations 7. Security considerations
The new DHCPv6 options described in this document could be sent in In untrusted networks, a rogue DHCPv6 server could send the new
untrusted networks by malicious people with a fake DHCPv6 server to DHCPv6 options described in this document. The booting clients could
confuse the booting clients. The clients could be provided with a then be provided with a wrong URL so that the boot either fails, or
wrong URL so that the boot either fails, or even worse, the client even worse, the client boots the wrong operating system which has
boots the wrong operating system which has been provided by a been provided by a malicious file server. To prevent this kind of
malicious file server. To prevent this kind of attack, clients attack, clients can use authentication of DHCPv6 messages (see
SHOULD use authentication of DHCPv6 messages (see chapter 21. in chapter 21. in [RFC3315]).
[RFC3315]).
Note also that DHCPv6 messages are sent unencrypted by default. So Note also that DHCPv6 messages are sent unencrypted by default. So
the boot file URL options are sent unencrypted over the network, too. the boot file URL options are sent unencrypted over the network, too.
This can become a security risk since the URLs can contain sensitive This can become a security risk since the URLs can contain sensitive
information like user names and passwords (for example a URL like information like user names and passwords (for example a URL like
"ftp://username:password@servername/path/file"). At the current "ftp://username:password@servername/path/file"). At the current
point in time, there is no possibility to send encrypted DHCPv6 point in time, there is no possibility to send encrypted DHCPv6
messages, so it is strongly recommended not to use sensitive messages, so it is strongly recommended not to use sensitive
information in the URLs in untrusted networks. information in the URLs in untrusted networks.
Even if the DHCPv6 transaction is secured, this does not protect
against attacks on the bootfile download channel. Consequently, we
recommend that either a protocol like HTTPS (see [RFC2817] and
[RFC2818]) be used to prevent spoofing, or that the boot loader
implementation implement a mechanism for signing boot images and a
configurable signing key in memory, so that if a malicious image is
provided, it can be detected and rejected.
8. Acknowledgements 8. Acknowledgements
The authors would like to thank Ruth Li, Dong Wei, Kathryn Hampton, The authors would like to thank Ruth Li, Dong Wei, Kathryn Hampton,
Phil Dorah, Richard Chan, and Fiona Jensen for discussions that led Phil Dorah, Richard Chan, and Fiona Jensen for discussions that led
to this document. to this document.
The authors would also like to thank Ketan P. Pancholi and Alfred The authors would also like to thank Ketan P. Pancholi, Alfred
Hoenes for corrections and suggestions. Hoenes, Gabriel Montenegro and Ted Lemon for corrections and
suggestions.
9. References 9. References
9.1. Normative References 9.1. Normative References
[PXE21] Johnston, M., "Preboot Execution Environment (PXE) [PXE21] Johnston, M., "Preboot Execution Environment (PXE)
Specification", September 1999, Specification", September 1999,
<http://www.pix.net/software/pxeboot/archive/pxespec.pdf>. <http://www.pix.net/software/pxeboot/archive/pxespec.pdf>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003. IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3617] Lear, E., "Uniform Resource Identifier (URI) Scheme and
Applicability Statement for the Trivial File Transfer
Protocol (TFTP)", RFC 3617, October 2003.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, January 2005. RFC 3986, January 2005.
[RFC4173] Sarkar, P., Missimer, D., and C. Sapuntzakis, [RFC4173] Sarkar, P., Missimer, D., and C. Sapuntzakis,
"Bootstrapping Clients using the Internet Small Computer "Bootstrapping Clients using the Internet Small Computer
System Interface (iSCSI) Protocol", RFC 4173, System Interface (iSCSI) Protocol", RFC 4173,
September 2005. September 2005.
[RFC4578] Johnston, M. and S. Venaas, "Dynamic Host Configuration [RFC4578] Johnston, M. and S. Venaas, "Dynamic Host Configuration
skipping to change at page 10, line 40 skipping to change at page 10, line 46
[UEFI22] UEFI Forum, "Unified Extensible Firmware Interface [UEFI22] UEFI Forum, "Unified Extensible Firmware Interface
Specification, Version 2.2", September 2008, Specification, Version 2.2", September 2008,
<http://www.uefi.org/>. <http://www.uefi.org/>.
9.2. Informative References 9.2. Informative References
[RFC1350] Sollins, K., "The TFTP Protocol (Revision 2)", STD 33, [RFC1350] Sollins, K., "The TFTP Protocol (Revision 2)", STD 33,
RFC 1350, July 1992. RFC 1350, July 1992.
[RFC2090] Emberson, A., "TFTP Multicast Option", RFC 2090,
February 1997.
[RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H., [RFC2616] Fielding, R., Gettys, J., Mogul, J., Frystyk, H.,
Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext Masinter, L., Leach, P., and T. Berners-Lee, "Hypertext
Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999. Transfer Protocol -- HTTP/1.1", RFC 2616, June 1999.
[RFC2817] Khare, R. and S. Lawrence, "Upgrading to TLS Within
HTTP/1.1", RFC 2817, May 2000.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000.
[RFC3617] Lear, E., "Uniform Resource Identifier (URI) Scheme and
Applicability Statement for the Trivial File Transfer
Protocol (TFTP)", RFC 3617, October 2003.
[RFC906] Finlayson, R., "Bootstrap Loading using TFTP", RFC 906, [RFC906] Finlayson, R., "Bootstrap Loading using TFTP", RFC 906,
June 1984. June 1984.
Authors' Addresses Authors' Addresses
Thomas H. Huth Thomas H. Huth
IBM Germany Research & Development GmbH IBM Germany Research & Development GmbH
Schoenaicher Strasse 220 Schoenaicher Strasse 220
Boeblingen 71032 Boeblingen 71032
Germany Germany
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