draft-ietf-dhc-options-1533update-04.txt   draft-ietf-dhc-options-1533update-05.txt 
Network Working Group S. Alexander Network Working Group S. Alexander
INTERNET DRAFT Silicon Graphics, Inc. INTERNET DRAFT Silicon Graphics, Inc.
Obsoletes: draft-ietf-dhc-options-1533update-03.txt R. Droms Obsoletes: draft-ietf-dhc-options-1533update-04.txt R. Droms
Bucknell University Bucknell University
May 1996 November 1996
Expires November 1996 Expires May 1997
DHCP Options and BOOTP Vendor Extensions DHCP Options and BOOTP Vendor Extensions
<draft-ietf-dhc-options-1533update-04.txt> <draft-ietf-dhc-options-1533update-05.txt>
Status of this memo Status of this memo
This document is an Internet-Draft. Internet-Drafts are working This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, documents of the Internet Engineering Task Force (IETF), its areas,
and its working groups. Note that other groups may also distribute and its working groups. Note that other groups may also distribute
working documents as Internet-Drafts. 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
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options will be specified in separate RFCs. The current list of options will be specified in separate RFCs. The current list of
valid options is also available in ftp://ftp.isi.edu/in- valid options is also available in ftp://ftp.isi.edu/in-
notes/iana/assignments [22]. notes/iana/assignments [22].
All of the vendor information extensions defined in RFC 1497 [2] may All of the vendor information extensions defined in RFC 1497 [2] may
be used as DHCP options. The definitions given in RFC 1497 are be used as DHCP options. The definitions given in RFC 1497 are
included in this document, which supersedes RFC 1497. All of the included in this document, which supersedes RFC 1497. All of the
DHCP options defined in this document, except for those specific to DHCP options defined in this document, except for those specific to
DHCP as defined in section 9, may be used as BOOTP vendor information DHCP as defined in section 9, may be used as BOOTP vendor information
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extensions. extensions.
Table of Contents Table of Contents
1. Introduction .............................................. 2 1. Introduction .............................................. 2
2. BOOTP Extension/DHCP Option Field Format .................. 4 2. BOOTP Extension/DHCP Option Field Format .................. 4
3. RFC 1497 Vendor Extensions ................................ 5 3. RFC 1497 Vendor Extensions ................................ 5
4. IP Layer Parameters per Host .............................. 12 4. IP Layer Parameters per Host .............................. 12
5. IP Layer Parameters per Interface ........................ 15 5. IP Layer Parameters per Interface ........................ 15
6. Link Layer Parameters per Interface ....................... 19 6. Link Layer Parameters per Interface ....................... 19
7. TCP Parameters ............................................ 20 7. TCP Parameters ............................................ 20
8. Application and Service Parameters ........................ 21 8. Application and Service Parameters ........................ 21
9. DHCP Extensions ........................................... 29 9. DHCP Extensions ........................................... 29
10. Defining new extensions ................................... 36 10. Defining new extensions ................................... 35
11. Acknowledgements .......................................... 36 11. Acknowledgements .......................................... 35
12. References ................................................ 37 12. References ................................................ 36
13. Security Considerations ................................... 38 13. Security Considerations ................................... 37
14. Authors' Addresses ........................................ 38 14. Authors' Addresses ........................................ 37
1. Introduction 1. Introduction
This document specifies options for use with both the Dynamic Host This document specifies options for use with both the Dynamic Host
Configuration Protocol and the Bootstrap Protocol. Configuration Protocol and the Bootstrap Protocol.
The full description of DHCP packet formats may be found in the DHCP The full description of DHCP packet formats may be found in the DHCP
specification document [1], and the full description of BOOTP packet specification document [1], and the full description of BOOTP packet
formats may be found in the BOOTP specification document [3]. This formats may be found in the BOOTP specification document [3]. This
document defines the format of information in the last field of DHCP document defines the format of information in the last field of DHCP
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DHCP and BOOTP. Section 9 defines options used only in DHCP. DHCP and BOOTP. Section 9 defines options used only in DHCP.
References further describing most of the options defined in sections References further describing most of the options defined in sections
2-6 can be found in section 12. The use of the options defined in 2-6 can be found in section 12. The use of the options defined in
section 9 is described in the DHCP specification [1]. section 9 is described in the DHCP specification [1].
Information on registering new options is contained in section 10. Information on registering new options is contained in section 10.
This document updates the definition of DHCP/BOOTP options that This document updates the definition of DHCP/BOOTP options that
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appears in RFC1533. The classing mechanism has been extended to appears in RFC1533. The classing mechanism has been extended to
include vendor classes and user classes as described in section 8.4, include vendor classes as described in section 8.4 and 9.13. The new
9.13 and 9.15. The new procedure for defining new DHCP/BOOTP options procedure for defining new DHCP/BOOTP options in described in section
in described in section 10. Several new options, including NIS+ 10. Several new options, including NIS+ domain and servers, Mobile
domain and servers, Mobile IP home agent, SMTP server, TFTP server IP home agent, SMTP server, TFTP server and Bootfile server, have
and Bootfile server, have been added. Text giving definitions used been added. Text giving definitions used throughout the document has
throughout the document has been added in section 1.1. Text been added in section 1.1. Text emphasizing the need for uniqueness
emphasizing the need for uniqueness of client-identifiers has been of client-identifiers has been added to section 9.14.
added to section 9.14.
1.1 Requirements 1.1 Requirements
Throughout this document, the words that are used to define the Throughout this document, the words that are used to define the
significance of particular requirements are capitalized. These words significance of particular requirements are capitalized. These words
are: are:
o "MUST" o "MUST"
This word or the adjective "REQUIRED" means that the This word or the adjective "REQUIRED" means that the
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described with this label. described with this label.
o "MAY" o "MAY"
This word or the adjective "OPTIONAL" means that this item is This word or the adjective "OPTIONAL" means that this item is
truly optional. One vendor may choose to include the item truly optional. One vendor may choose to include the item
because a particular marketplace requires it or because it because a particular marketplace requires it or because it
enhances the product, for example; another vendor may omit the enhances the product, for example; another vendor may omit the
same item. same item.
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1. Terminology 1.2 Terminology
This document uses the following terms: This document uses the following terms:
o "DHCP client" o "DHCP client"
A DHCP client or "client" is an Internet host using DHCP to obtain A DHCP client or "client" is an Internet host using DHCP to obtain
configuration parameters such as a network address. configuration parameters such as a network address.
o "DHCP server" o "DHCP server"
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Any options defined subsequent to this document MUST contain a Any options defined subsequent to this document MUST contain a
length octet even if the length is fixed or zero. length octet even if the length is fixed or zero.
All multi-octet quantities are in network byte-order. All multi-octet quantities are in network byte-order.
When used with BOOTP, the first four octets of the vendor information When used with BOOTP, the first four octets of the vendor information
field have been assigned to the "magic cookie" (as suggested in RFC field have been assigned to the "magic cookie" (as suggested in RFC
951). This field identifies the mode in which the succeeding data is 951). This field identifies the mode in which the succeeding data is
to be interpreted. The value of the magic cookie is the 4 octet to be interpreted. The value of the magic cookie is the 4 octet
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dotted decimal 99.130.83.99 (or hexadecimal number 63.82.53.63) in dotted decimal 99.130.83.99 (or hexadecimal number 63.82.53.63) in
network byte order. network byte order.
All of the "vendor extensions" defined in RFC 1497 are also DHCP All of the "vendor extensions" defined in RFC 1497 are also DHCP
options. options.
Option codes 128 to 254 (decimal) are reserved for site-specific Option codes 128 to 254 (decimal) are reserved for site-specific
options. options.
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The pad option can be used to cause subsequent fields to align on The pad option can be used to cause subsequent fields to align on
word boundaries. word boundaries.
The code for the pad option is 0, and its length is 1 octet. The code for the pad option is 0, and its length is 1 octet.
Code Code
+-----+ +-----+
| 0 | | 0 |
+-----+ +-----+
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3.2. End Option 3.2. End Option
The end option marks the end of valid information in the vendor The end option marks the end of valid information in the vendor
field. Subsequent octets should be filled with pad options. field. Subsequent octets should be filled with pad options.
The code for the end option is 255, and its length is 1 octet. The code for the end option is 255, and its length is 1 octet.
Code Code
+-----+ +-----+
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Code Len Subnet Mask Code Len Subnet Mask
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
| 1 | 4 | m1 | m2 | m3 | m4 | | 1 | 4 | m1 | m2 | m3 | m4 |
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
3.4. Time Offset 3.4. Time Offset
The time offset field specifies the offset of the client's subnet in The time offset field specifies the offset of the client's subnet in
seconds from Coordinated Universal Time (UTC). The offset is seconds from Coordinated Universal Time (UTC). The offset is
expressed as a two's complement 32-bit integer. The code for the time expressed as a two's complement 32-bit integer. A positive offset
offset option is 2, and its length is 4 octets. indicates a location east of the zero meridian and a negative offset
indicates a location west of the zero meridian.
The code for the time offset option is 2, and its length is 4 octets.
Code Len Time Offset Code Len Time Offset
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
| 2 | 4 | n1 | n2 | n3 | n4 | | 2 | 4 | n1 | n2 | n3 | n4 |
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
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3.5. Router Option 3.5. Router Option
The router option specifies a list of IP addresses for routers on the The router option specifies a list of IP addresses for routers on the
client's subnet. Routers SHOULD be listed in order of preference. client's subnet. Routers SHOULD be listed in order of preference.
The code for the router option is 3. The minimum length for the The code for the router option is 3. The minimum length for the
router option is 4 octets, and the length MUST always be a multiple router option is 4 octets, and the length MUST always be a multiple
of 4. of 4.
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The code for the name server option is 5. The minimum length for The code for the name server option is 5. The minimum length for
this option is 4 octets, and the length MUST always be a multiple of this option is 4 octets, and the length MUST always be a multiple of
4. 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
| 5 | n | a1 | a2 | a3 | a4 | a1 | a2 | ... | 5 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
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3.8. Domain Name Server Option 3.8. Domain Name Server Option
The domain name server option specifies a list of Domain Name System The domain name server option specifies a list of Domain Name System
(STD 13, RFC 1035 [8]) name servers available to the client. Servers (STD 13, RFC 1035 [8]) name servers available to the client. Servers
SHOULD be listed in order of preference. SHOULD be listed in order of preference.
The code for the domain name server option is 6. The minimum length The code for the domain name server option is 6. The minimum length
for this option is 4 octets, and the length MUST always be a multiple for this option is 4 octets, and the length MUST always be a multiple
of 4. of 4.
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of preference. of preference.
The code for the log server option is 8. The minimum length for this The code for the log server option is 8. The minimum length for this
option is 4 octets, and the length MUST always be a multiple of 4. option is 4 octets, and the length MUST always be a multiple of 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
| 8 | n | a1 | a2 | a3 | a4 | a1 | a2 | ... | 8 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
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3.11. LPR Server Option 3.11. LPR Server Option
The LPR server option specifies a list of RFC 1179 [10] line printer The LPR server option specifies a list of RFC 1179 [10] line printer
servers available to the client. Servers SHOULD be listed in order servers available to the client. Servers SHOULD be listed in order
of preference. of preference.
The code for the LPR server option is 9. The minimum length for this The code for the LPR server option is 9. The minimum length for this
option is 4 octets, and the length MUST always be a multiple of 4. option is 4 octets, and the length MUST always be a multiple of 4.
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of preference. of preference.
The code for this option is 11. The minimum length for this option The code for this option is 11. The minimum length for this option
is 4 octets, and the length MUST always be a multiple of 4. is 4 octets, and the length MUST always be a multiple of 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
| 11 | n | a1 | a2 | a3 | a4 | a1 | a2 | ... | 11 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
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3.14. Host Name Option 3.14. Host Name Option
This option specifies the name of the client. The name may or may This option specifies the name of the client. The name may or may
not be qualified with the local domain name (see section 3.17 for the not be qualified with the local domain name (see section 3.17 for the
preferred way to retrieve the domain name). See RFC 1035 for preferred way to retrieve the domain name). See RFC 1035 for
character set restrictions. character set restrictions.
The code for this option is 12, and its minimum length is 1. The code for this option is 12, and its minimum length is 1.
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path is formatted as a character string consisting of characters from path is formatted as a character string consisting of characters from
the NVT ASCII character set. the NVT ASCII character set.
The code for this option is 14. Its minimum length is 1. The code for this option is 14. Its minimum length is 1.
Code Len Dump File Pathname Code Len Dump File Pathname
+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+---
| 14 | n | n1 | n2 | n3 | n4 | ... | 14 | n | n1 | n2 | n3 | n4 | ...
+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+---
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3.17. Domain Name 3.17. Domain Name
This option specifies the domain name that client should use when This option specifies the domain name that client should use when
resolving hostnames via the Domain Name System. resolving hostnames via the Domain Name System.
The code for this option is 15. Its minimum length is 1. The code for this option is 15. Its minimum length is 1.
Code Len Domain Name Code Len Domain Name
+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+--
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disk. The path is formatted as a character string consisting of disk. The path is formatted as a character string consisting of
characters from the NVT ASCII character set. characters from the NVT ASCII character set.
The code for this option is 17. Its minimum length is 1. The code for this option is 17. Its minimum length is 1.
Code Len Root Disk Pathname Code Len Root Disk Pathname
+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+---
| 17 | n | n1 | n2 | n3 | n4 | ... | 17 | n | n1 | n2 | n3 | n4 | ...
+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+---
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3.20. Extensions Path 3.20. Extensions Path
A string to specify a file, retrievable via TFTP, which contains A string to specify a file, retrievable via TFTP, which contains
information which can be interpreted in the same way as the 64-octet information which can be interpreted in the same way as the 64-octet
vendor-extension field within the BOOTP response, with the following vendor-extension field within the BOOTP response, with the following
exceptions: exceptions:
- the length of the file is unconstrained; - the length of the file is unconstrained;
- all references to Tag 18 (i.e., instances of the - all references to Tag 18 (i.e., instances of the
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layer for packet forwarding. A value of 0 means disable IP layer for packet forwarding. A value of 0 means disable IP
forwarding, and a value of 1 means enable IP forwarding. forwarding, and a value of 1 means enable IP forwarding.
The code for this option is 19, and its length is 1. The code for this option is 19, and its length is 1.
Code Len Value Code Len Value
+-----+-----+-----+ +-----+-----+-----+
| 19 | 1 | 0/1 | | 19 | 1 | 0/1 |
+-----+-----+-----+ +-----+-----+-----+
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4.2. Non-Local Source Routing Enable/Disable Option 4.2. Non-Local Source Routing Enable/Disable Option
This option specifies whether the client should configure its IP This option specifies whether the client should configure its IP
layer to allow forwarding of datagrams with non-local source routes layer to allow forwarding of datagrams with non-local source routes
(see Section 3.3.5 of [4] for a discussion of this topic). A value (see Section 3.3.5 of [4] for a discussion of this topic). A value
of 0 means disallow forwarding of such datagrams, and a value of 1 of 0 means disallow forwarding of such datagrams, and a value of 1
means allow forwarding. means allow forwarding.
The code for this option is 20, and its length is 1. The code for this option is 20, and its length is 1.
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Code Len Address 1 Mask 1 Code Len Address 1 Mask 1
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
| 21 | n | a1 | a2 | a3 | a4 | m1 | m2 | m3 | m4 | | 21 | n | a1 | a2 | a3 | a4 | m1 | m2 | m3 | m4 |
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
Address 2 Mask 2 Address 2 Mask 2
+-----+-----+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+-----+-----+---
| a1 | a2 | a3 | a4 | m1 | m2 | m3 | m4 | ... | a1 | a2 | a3 | a4 | m1 | m2 | m3 | m4 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+-----+-----+---
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4.4. Maximum Datagram Reassembly Size 4.4. Maximum Datagram Reassembly Size
This option specifies the maximum size datagram that the client This option specifies the maximum size datagram that the client
should be prepared to reassemble. The size is specified as a 16-bit should be prepared to reassemble. The size is specified as a 16-bit
unsigned integer. The minimum value legal value is 576. unsigned integer. The minimum value legal value is 576.
The code for this option is 22, and its length is 2. The code for this option is 22, and its length is 2.
Code Len Size Code Len Size
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MTU values discovered by the mechanism defined in RFC 1191 [12]. The MTU values discovered by the mechanism defined in RFC 1191 [12]. The
timeout is specified as a 32-bit unsigned integer. timeout is specified as a 32-bit unsigned integer.
The code for this option is 24, and its length is 4. The code for this option is 24, and its length is 4.
Code Len Timeout Code Len Timeout
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
| 24 | 4 | t1 | t2 | t3 | t4 | | 24 | 4 | t1 | t2 | t3 | t4 |
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
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4.7. Path MTU Plateau Table Option 4.7. Path MTU Plateau Table Option
This option specifies a table of MTU sizes to use when performing This option specifies a table of MTU sizes to use when performing
Path MTU Discovery as defined in RFC 1191. The table is formatted as Path MTU Discovery as defined in RFC 1191. The table is formatted as
a list of 16-bit unsigned integers, ordered from smallest to largest. a list of 16-bit unsigned integers, ordered from smallest to largest.
The minimum MTU value cannot be smaller than 68. The minimum MTU value cannot be smaller than 68.
The code for this option is 25. Its minimum length is 2, and the The code for this option is 25. Its minimum length is 2, and the
length MUST be a multiple of 2. length MUST be a multiple of 2.
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specified as a 16-bit unsigned integer. The minimum legal value for specified as a 16-bit unsigned integer. The minimum legal value for
the MTU is 68. the MTU is 68.
The code for this option is 26, and its length is 2. The code for this option is 26, and its length is 2.
Code Len MTU Code Len MTU
+-----+-----+-----+-----+ +-----+-----+-----+-----+
| 26 | 2 | m1 | m2 | | 26 | 2 | m1 | m2 |
+-----+-----+-----+-----+ +-----+-----+-----+-----+
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5.2. All Subnets are Local Option 5.2. All Subnets are Local Option
This option specifies whether or not the client may assume that all This option specifies whether or not the client may assume that all
subnets of the IP network to which the client is connected use the subnets of the IP network to which the client is connected use the
same MTU as the subnet of that network to which the client is same MTU as the subnet of that network to which the client is
directly connected. A value of 1 indicates that all subnets share directly connected. A value of 1 indicates that all subnets share
the same MTU. A value of 0 means that the client should assume that the same MTU. A value of 0 means that the client should assume that
some subnets of the directly connected network may have smaller MTUs. some subnets of the directly connected network may have smaller MTUs.
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should not perform mask discovery. A value of 1 means that the should not perform mask discovery. A value of 1 means that the
client should perform mask discovery. client should perform mask discovery.
The code for this option is 29, and its length is 1. The code for this option is 29, and its length is 1.
Code Len Value Code Len Value
+-----+-----+-----+ +-----+-----+-----+
| 29 | 1 | 0/1 | | 29 | 1 | 0/1 |
+-----+-----+-----+ +-----+-----+-----+
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5.5. Mask Supplier Option 5.5. Mask Supplier Option
This option specifies whether or not the client should respond to This option specifies whether or not the client should respond to
subnet mask requests using ICMP. A value of 0 indicates that the subnet mask requests using ICMP. A value of 0 indicates that the
client should not respond. A value of 1 means that the client should client should not respond. A value of 1 means that the client should
respond. respond.
The code for this option is 30, and its length is 1. The code for this option is 30, and its length is 1.
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This option specifies the address to which the client should transmit This option specifies the address to which the client should transmit
router solicitation requests. router solicitation requests.
The code for this option is 32, and its length is 4. The code for this option is 32, and its length is 4.
Code Len Address Code Len Address
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
| 32 | 4 | a1 | a2 | a3 | a4 | | 32 | 4 | a1 | a2 | a3 | a4 |
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
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5.8. Static Route Option 5.8. Static Route Option
This option specifies a list of static routes that the client should This option specifies a list of static routes that the client should
install in its routing cache. If multiple routes to the same install in its routing cache. If multiple routes to the same
destination are specified, they are listed in descending order of destination are specified, they are listed in descending order of
priority. priority.
The routes consist of a list of IP address pairs. The first address The routes consist of a list of IP address pairs. The first address
is the destination address, and the second address is the router for is the destination address, and the second address is the router for
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Code Len Destination 1 Router 1 Code Len Destination 1 Router 1
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
| 33 | n | d1 | d2 | d3 | d4 | r1 | r2 | r3 | r4 | | 33 | n | d1 | d2 | d3 | d4 | r1 | r2 | r3 | r4 |
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
Destination 2 Router 2 Destination 2 Router 2
+-----+-----+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+-----+-----+---
| d1 | d2 | d3 | d4 | r1 | r2 | r3 | r4 | ... | d1 | d2 | d3 | d4 | r1 | r2 | r3 | r4 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+-----+-----+---
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6. Link Layer Parameters per Interface 6. Link Layer Parameters per Interface
This section lists the options that affect the operation of the data This section lists the options that affect the operation of the data
link layer on a per-interface basis. link layer on a per-interface basis.
6.1. Trailer Encapsulation Option 6.1. Trailer Encapsulation Option
This option specifies whether or not the client should negotiate the This option specifies whether or not the client should negotiate the
use of trailers (RFC 893 [14]) when using the ARP protocol. A value use of trailers (RFC 893 [14]) when using the ARP protocol. A value
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client should use RFC 894 encapsulation. A value of 1 means that the client should use RFC 894 encapsulation. A value of 1 means that the
client should use RFC 1042 encapsulation. client should use RFC 1042 encapsulation.
The code for this option is 36, and its length is 1. The code for this option is 36, and its length is 1.
Code Len Value Code Len Value
+-----+-----+-----+ +-----+-----+-----+
| 36 | 1 | 0/1 | | 36 | 1 | 0/1 |
+-----+-----+-----+ +-----+-----+-----+
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7. TCP Parameters 7. TCP Parameters
This section lists the options that affect the operation of the TCP This section lists the options that affect the operation of the TCP
layer on a per-interface basis. layer on a per-interface basis.
7.1. TCP Default TTL Option 7.1. TCP Default TTL Option
This option specifies the default TTL that the client should use when This option specifies the default TTL that the client should use when
sending TCP segments. The value is represented as an 8-bit unsigned sending TCP segments. The value is represented as an 8-bit unsigned
skipping to change at page 21, line 5 skipping to change at page 21, line 5
should not be sent. A value of 1 indicates that a garbage octet should not be sent. A value of 1 indicates that a garbage octet
should be sent. should be sent.
The code for this option is 39, and its length is 1. The code for this option is 39, and its length is 1.
Code Len Value Code Len Value
+-----+-----+-----+ +-----+-----+-----+
| 39 | 1 | 0/1 | | 39 | 1 | 0/1 |
+-----+-----+-----+ +-----+-----+-----+
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8. Application and Service Parameters 8. Application and Service Parameters
This section details some miscellaneous options used to configure This section details some miscellaneous options used to configure
miscellaneous applications and services. miscellaneous applications and services.
8.1. Network Information Service Domain Option 8.1. Network Information Service Domain Option
This option specifies the name of the client's NIS [17] domain. The This option specifies the name of the client's NIS [17] domain. The
domain is formatted as a character string consisting of characters domain is formatted as a character string consisting of characters
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of preference. of preference.
The code for this option is 42. Its minimum length is 4, and the The code for this option is 42. Its minimum length is 4, and the
length MUST be a multiple of 4. length MUST be a multiple of 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
| 42 | n | a1 | a2 | a3 | a4 | a1 | a2 | ... | 42 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
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8.4. Vendor Specific Information 8.4. Vendor Specific Information
This option is used by clients and servers to exchange vendor- This option is used by clients and servers to exchange vendor-
specific information. The information is an opaque object of n specific information. The information is an opaque object of n
octets, presumably interpreted by vendor-specific code on the clients octets, presumably interpreted by vendor-specific code on the clients
and servers. The definition of this information is vendor specific. and servers. The definition of this information is vendor specific.
The vendor is indicated in the vendor class identifier option. The vendor is indicated in the vendor class identifier option.
Servers not equipped to interpret the vendor-specific information Servers not equipped to interpret the vendor-specific information
sent by a client MUST ignore it (although it may be reported). sent by a client MUST ignore it (although it may be reported).
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+-----+-----+-----+-----+--- +-----+-----+-----+-----+---
When encapsulated vendor-specific extensions are used, the When encapsulated vendor-specific extensions are used, the
information bytes 1-n have the following format: information bytes 1-n have the following format:
Code Len Data item Code Len Data item Code Code Len Data item Code Len Data item Code
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
| T1 | n | d1 | d2 | ... | T2 | n | D1 | D2 | ... | ... | | T1 | n | d1 | d2 | ... | T2 | n | D1 | D2 | ... | ... |
+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+-----+
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8.5. NetBIOS over TCP/IP Name Server Option 8.5. NetBIOS over TCP/IP Name Server Option
The NetBIOS name server (NBNS) option specifies a list of RFC The NetBIOS name server (NBNS) option specifies a list of RFC
1001/1002 [19] [20] NBNS name servers listed in order of preference. 1001/1002 [19] [20] NBNS name servers listed in order of preference.
The code for this option is 44. The minimum length of the option is The code for this option is 44. The minimum length of the option is
4 octets, and the length must always be a multiple of 4. 4 octets, and the length must always be a multiple of 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
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Value Node Type Value Node Type
----- --------- ----- ---------
0x1 B-node 0x1 B-node
0x2 P-node 0x2 P-node
0x4 M-node 0x4 M-node
0x8 H-node 0x8 H-node
In the above chart, the notation '0x' indicates a number in base-16 In the above chart, the notation '0x' indicates a number in base-16
(hexadecimal). (hexadecimal).
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The code for this option is 46. The length of this option is always The code for this option is 46. The length of this option is always
1. 1.
Code Len Node Type Code Len Node Type
+-----+-----+-----------+ +-----+-----+-----------+
| 46 | 1 | see above | | 46 | 1 | see above |
+-----+-----+-----------+ +-----+-----+-----------+
8.8. NetBIOS over TCP/IP Scope Option 8.8. NetBIOS over TCP/IP Scope Option
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preference. preference.
The code for this option is 48. The minimum length of this option is The code for this option is 48. The minimum length of this option is
4 octets, and the length MUST be a multiple of 4. 4 octets, and the length MUST be a multiple of 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
+-----+-----+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+-----+-----+---
| 48 | n | a1 | a2 | a3 | a4 | a1 | a2 | ... | 48 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+-----+-----+-----+---
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8.10. X Window System Display Manager Option 8.10. X Window System Display Manager Option
This option specifies a list of IP addresses of systems that are This option specifies a list of IP addresses of systems that are
running the X Window System Display Manager and are available to the running the X Window System Display Manager and are available to the
client. client.
Addresses SHOULD be listed in order of preference. Addresses SHOULD be listed in order of preference.
The code for the this option is 49. The minimum length of this option The code for the this option is 49. The minimum length of this option
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preference. preference.
The code for this option is 65. Its minimum length is 4, and the The code for this option is 65. Its minimum length is 4, and the
length MUST be a multiple of 4. length MUST be a multiple of 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
| 65 | n | a1 | a2 | a3 | a4 | a1 | a2 | ... | 65 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
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8.13. Mobile IP Home Agent option 8.13. Mobile IP Home Agent option
This option specifies a list of IP addresses indicating mobile IP This option specifies a list of IP addresses indicating mobile IP
home agents available to the client. Agents SHOULD be listed in home agents available to the client. Agents SHOULD be listed in
order of preference. order of preference.
The code for this option is 68. Its minimum length is 0 (indicating The code for this option is 68. Its minimum length is 0 (indicating
no home agents are available) and the length MUST be a multiple of 4. no home agents are available) and the length MUST be a multiple of 4.
It is expected that the usual length will be four octets, containing It is expected that the usual length will be four octets, containing
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The code for the POP3 server option is 70. The minimum length for The code for the POP3 server option is 70. The minimum length for
this option is 4 octets, and the length MUST always be a multiple of this option is 4 octets, and the length MUST always be a multiple of
4. 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
| 70 | n | a1 | a2 | a3 | a4 | a1 | a2 | ... | 70 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
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8.16. Network News Transport Protocol (NNTP) Server Option 8.16. Network News Transport Protocol (NNTP) Server Option
The NNTP server option specifies a list of NNTP available to the The NNTP server option specifies a list of NNTP available to the
client. Servers SHOULD be listed in order of preference. client. Servers SHOULD be listed in order of preference.
The code for the NNTP server option is 71. The minimum length for The code for the NNTP server option is 71. The minimum length for
this option is 4 octets, and the length MUST always be a multiple of this option is 4 octets, and the length MUST always be a multiple of
4. 4.
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The code for the Finger server option is 73. The minimum length for The code for the Finger server option is 73. The minimum length for
this option is 4 octets, and the length MUST always be a multiple of this option is 4 octets, and the length MUST always be a multiple of
4. 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
| 73 | n | a1 | a2 | a3 | a4 | a1 | a2 | ... | 73 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
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8.19. Default Internet Relay Chat (IRC) Server Option 8.19. Default Internet Relay Chat (IRC) Server Option
The IRC server option specifies a list of IRC available to the The IRC server option specifies a list of IRC available to the
client. Servers SHOULD be listed in order of preference. client. Servers SHOULD be listed in order of preference.
The code for the IRC server option is 74. The minimum length for The code for the IRC server option is 74. The minimum length for
this option is 4 octets, and the length MUST always be a multiple of this option is 4 octets, and the length MUST always be a multiple of
4. 4.
skipping to change at page 29, line 5 skipping to change at page 29, line 5
The code for the StreetTalk Directory Assistance server option is 76. The code for the StreetTalk Directory Assistance server option is 76.
The minimum length for this option is 4 octets, and the length MUST The minimum length for this option is 4 octets, and the length MUST
always be a multiple of 4. always be a multiple of 4.
Code Len Address 1 Address 2 Code Len Address 1 Address 2
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
| 76 | n | a1 | a2 | a3 | a4 | a1 | a2 | ... | 76 | n | a1 | a2 | a3 | a4 | a1 | a2 | ...
+-----+-----+-----+-----+-----+-----+-----+-----+-- +-----+-----+-----+-----+-----+-----+-----+-----+--
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9. DHCP Extensions 9. DHCP Extensions
This section details the options that are specific to DHCP. This section details the options that are specific to DHCP.
9.1. Requested IP Address 9.1. Requested IP Address
This option is used in a client request (DHCPDISCOVER) to allow the This option is used in a client request (DHCPDISCOVER) to allow the
client to request that a particular IP address be assigned. client to request that a particular IP address be assigned.
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This option is used to indicate that the DHCP 'sname' or 'file' This option is used to indicate that the DHCP 'sname' or 'file'
fields are being overloaded by using them to carry DHCP options. A fields are being overloaded by using them to carry DHCP options. A
DHCP server inserts this option if the returned parameters will DHCP server inserts this option if the returned parameters will
exceed the usual space allotted for options. exceed the usual space allotted for options.
If this option is present, the client interprets the specified If this option is present, the client interprets the specified
additional fields after it concludes interpretation of the standard additional fields after it concludes interpretation of the standard
option fields. option fields.
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The code for this option is 52, and its length is 1. Legal values The code for this option is 52, and its length is 1. Legal values
for this option are: for this option are:
Value Meaning Value Meaning
----- -------- ----- --------
1 the 'file' field is used to hold options 1 the 'file' field is used to hold options
2 the 'sname' field is used to hold options 2 the 'sname' field is used to hold options
3 both fields are used to hold options 3 both fields are used to hold options
skipping to change at page 31, line 5 skipping to change at page 31, line 5
This option is used to identify a bootfile when the 'file' field in This option is used to identify a bootfile when the 'file' field in
the DHCP header has been used for DHCP options. the DHCP header has been used for DHCP options.
The code for this option is 67, and its minimum length is 1. The code for this option is 67, and its minimum length is 1.
Code Len Bootfile name Code Len Bootfile name
+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+---
| 67 | n | c1 | c2 | c3 | ... | 67 | n | c1 | c2 | c3 | ...
+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+---
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9.6. DHCP Message Type 9.6. DHCP Message Type
This option is used to convey the type of the DHCP message. The code This option is used to convey the type of the DHCP message. The code
for this option is 53, and its length is 1. Legal values for this for this option is 53, and its length is 1. Legal values for this
option are: option are:
Value Message Type Value Message Type
----- ------------ ----- ------------
1 DHCPDISCOVER 1 DHCPDISCOVER
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The identifier is the IP address of the selected server. The identifier is the IP address of the selected server.
The code for this option is 54, and its length is 4. The code for this option is 54, and its length is 4.
Code Len Address Code Len Address
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
| 54 | 4 | a1 | a2 | a3 | a4 | | 54 | 4 | a1 | a2 | a3 | a4 |
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
DRAFT DHCP Options and BOOTP Vendor Extensions May 1996 DRAFT DHCP Options and BOOTP Vendor Extensions November 1996
9.8. Parameter Request List 9.8. Parameter Request List
This option is used by a DHCP client to request values for specified This option is used by a DHCP client to request values for specified
configuration parameters. The list of requested parameters is configuration parameters. The list of requested parameters is
specified as n octets, where each octet is a valid DHCP option code specified as n octets, where each octet is a valid DHCP option code
as defined in this document. as defined in this document.
The client MAY list the options in order of preference. The DHCP The client MAY list the options in order of preference. The DHCP
server is not required to return the options in the requested order, server is not required to return the options in the requested order,
skipping to change at page 33, line 5 skipping to change at page 33, line 5
octets of NVT ASCII text, which the client may display on an octets of NVT ASCII text, which the client may display on an
available output device. available output device.
The code for this option is 56 and its minimum length is 1. The code for this option is 56 and its minimum length is 1.
Code Len Text Code Len Text
+-----+-----+-----+-----+--- +-----+-----+-----+-----+---
| 56 | n | c1 | c2 | ... | 56 | n | c1 | c2 | ...
+-----+-----+-----+-----+--- +-----+-----+-----+-----+---
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9.10. Maximum DHCP Message Size 9.10. Maximum DHCP Message Size
This option specifies the maximum length DHCP message that it is This option specifies the maximum length DHCP message that it is
willing to accept. The length is specified as an unsigned 16-bit willing to accept. The length is specified as an unsigned 16-bit
integer. A client may use the maximum DHCP message size option in integer. A client may use the maximum DHCP message size option in
DHCPDISCOVER or DHCPREQUEST messages, but should not use the option DHCPDISCOVER or DHCPREQUEST messages, but should not use the option
in DHCPDECLINE messages. in DHCPDECLINE messages.
The code for this option is 57, and its length is 2. The minimum The code for this option is 57, and its length is 2. The minimum
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The value is in units of seconds, and is specified as a 32-bit The value is in units of seconds, and is specified as a 32-bit
unsigned integer. unsigned integer.
The code for this option is 59, and its length is 4. The code for this option is 59, and its length is 4.
Code Len T2 Interval Code Len T2 Interval
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
| 59 | 4 | t1 | t2 | t3 | t4 | | 59 | 4 | t1 | t2 | t3 | t4 |
+-----+-----+-----+-----+-----+-----+ +-----+-----+-----+-----+-----+-----+
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9.13. Vendor class identifier 9.13. Vendor class identifier
This option is used by DHCP clients to optionally identify the vendor This option is used by DHCP clients to optionally identify the vendor
type and configuration of a DHCP client. The information is a string type and configuration of a DHCP client. The information is a string
of n octets, interpreted by servers. Vendors may choose to define of n octets, interpreted by servers. Vendors may choose to define
specific vendor class identifiers to convey particular configuration specific vendor class identifiers to convey particular configuration
or other identification information about a client. For example, the or other identification information about a client. For example, the
identifier may encode the client's hardware configuration. Servers identifier may encode the client's hardware configuration. Servers
not equipped to interpret the class-specific information sent by a not equipped to interpret the class-specific information sent by a
skipping to change at page 35, line 5 skipping to change at page 35, line 5
hardware type of 0 (zero) should be used when the value field hardware type of 0 (zero) should be used when the value field
contains an identifier other than a hardware address (e.g. a fully contains an identifier other than a hardware address (e.g. a fully
qualified domain name). qualified domain name).
For correct identification of clients, each client's client- For correct identification of clients, each client's client-
identifier MUST be unique among the client-identifiers used on the identifier MUST be unique among the client-identifiers used on the
subnet to which the client is attached. Vendors and system subnet to which the client is attached. Vendors and system
administrators are responsible for choosing client-identifiers that administrators are responsible for choosing client-identifiers that
meet this requirement for uniqueness. meet this requirement for uniqueness.
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The code for this option is 61, and its minimum length is 2. The code for this option is 61, and its minimum length is 2.
Code Len Type Client-Identifier Code Len Type Client-Identifier
+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+---
| 61 | n | t1 | i1 | i2 | ... | 61 | n | t1 | i1 | i2 | ...
+-----+-----+-----+-----+-----+--- +-----+-----+-----+-----+-----+---
9.15. User Class Information
This option is used by a DHCP client to optionally identify the type
or category of user or applications it represents. The information
contained in this option is an NVT ASCII text object that represents
the user class of which the client is a member.
DHCP administrators may define specific user class identifiers to
convey information about a client's software configuration or about
its user's preferences. For example, an identifier may specify that
a particular DHCP client is a member of the class "accounting
auditors", which have special service needs such as a particular
database server.
Servers not equipped to interpret any of user classes specified by a
client MUST ignore it (although it may be reported). Otherwise,
servers SHOULD respond with the set of options corresponding to the
user class specified by the client. Further, if the server responds,
it MUST return this option to the client.
Clients which do not receive information for the user class requested
SHOULD make an attempt to operate without it, although they may do so
(and may announce they are doing so) in a degraded mode.
The code for this option is 77. The minimum length for this option
is two.
Code Len text1
+-----+-----+-----+-----+-----
| 77 | N | c1 | c2 | ...
+-----+-----+-----+-----+-----
DRAFT DHCP Options and BOOTP Vendor Extensions May 1996
10. Defining new extensions 10. Defining new extensions
The author of a new DHCP option will follow these steps to obtain The author of a new DHCP option will follow these steps to obtain
acceptance of the option as a part of the DHCP Internet Standard: acceptance of the option as a part of the DHCP Internet Standard:
1. The author devises the new option. 1. The author devises the new option.
2. The author requests a number for the new option from IANA by 2. The author requests a number for the new option from IANA by
contacting: contacting:
Internet Assigned Numbers Authority (IANA) Internet Assigned Numbers Authority (IANA)
USC/Information Sciences Institute USC/Information Sciences Institute
skipping to change at page 36, line 46 skipping to change at page 35, line 53
This procedure for defining new extensions will ensure that: This procedure for defining new extensions will ensure that:
* allocation of new option numbers is coordinated from a single * allocation of new option numbers is coordinated from a single
authority, authority,
* new options are reviewed for technical correctness and * new options are reviewed for technical correctness and
appropriateness, and appropriateness, and
* documentation for new options is complete and published. * documentation for new options is complete and published.
11. Acknowledgements 11. Acknowledgements
The authors would like to thank Philip Almquist for his feedback The author thanks the many (and too numerous to mention!)
on this document. The comments of the DHCP Working Group are
also gratefully acknowledged. In particular, Mike Carney and
Jon Dreyer from SunSelect suggested the current format of the
Vendor-specific Information option.
RFC 1497 is based on earlier work by Philip Prindeville, with DRAFT DHCP Options and BOOTP Vendor Extensions November 1996
help from Drew Perkins, Bill Croft, and Steve Deering.
DRAFT DHCP Options and BOOTP Vendor Extensions May 1996 members of the DHC WG for their tireless and ongoing efforts in
the development of DHCP and this document.
The efforts of J Allard, Mike Carney, Dave Lapp, Fred Lien and
John Mendonca in organizing DHCP interoperability testing
sessions are gratefully acknowledged.
The development of this document was supported in part by grants
from the Corporation for National Research Initiatives (CNRI),
Bucknell University and Sun Microsystems.
12. References 12. References
[1] Droms, R., "Dynamic Host Configuration Protocol", RFC 1531, [1] Droms, R., "Dynamic Host Configuration Protocol", RFC 1531,
Bucknell University, October 1993. Bucknell University, October 1993.
[2] Reynolds, J., "BOOTP Vendor Information Extensions", RFC 1497, [2] Reynolds, J., "BOOTP Vendor Information Extensions", RFC 1497,
USC/Information Sciences Institute, August 1993. USC/Information Sciences Institute, August 1993.
[3] Croft, W., and J. Gilmore, "Bootstrap Protocol", RFC 951, [3] Croft, W., and J. Gilmore, "Bootstrap Protocol", RFC 951,
skipping to change at page 37, line 42 skipping to change at page 37, line 5
[8] Mockapetris, P., "Domain Names - Implementation and [8] Mockapetris, P., "Domain Names - Implementation and
Specification", STD 13, RFC 1035, USC/Information Sciences Specification", STD 13, RFC 1035, USC/Information Sciences
Institute, November 1987. Institute, November 1987.
[9] Postel, J., "Quote of the Day Protocol", STD 23, RFC 865, [9] Postel, J., "Quote of the Day Protocol", STD 23, RFC 865,
USC/Information Sciences Institute, May 1983. USC/Information Sciences Institute, May 1983.
[10] McLaughlin, L., "Line Printer Daemon Protocol", RFC 1179, The [10] McLaughlin, L., "Line Printer Daemon Protocol", RFC 1179, The
Wollongong Group, August 1990. Wollongong Group, August 1990.
DRAFT DHCP Options and BOOTP Vendor Extensions November 1996
[11] Accetta, M., "Resource Location Protocol", RFC 887, CMU, [11] Accetta, M., "Resource Location Protocol", RFC 887, CMU,
December 1983. December 1983.
[12] Mogul, J. and S. Deering, "Path MTU Discovery", RFC 1191, [12] Mogul, J. and S. Deering, "Path MTU Discovery", RFC 1191,
DECWRL, Stanford University, November 1990. DECWRL, Stanford University, November 1990.
[13] Deering, S., "ICMP Router Discovery Messages", RFC 1256, [13] Deering, S., "ICMP Router Discovery Messages", RFC 1256,
Xerox PARC, September 1991. Xerox PARC, September 1991.
[14] Leffler, S. and M. Karels, "Trailer Encapsulations", RFC 893, [14] Leffler, S. and M. Karels, "Trailer Encapsulations", RFC 893,
U. C. Berkeley, April 1984. U. C. Berkeley, April 1984.
[15] Hornig, C., "Standard for the Transmission of IP Datagrams over [15] Hornig, C., "Standard for the Transmission of IP Datagrams over
DRAFT DHCP Options and BOOTP Vendor Extensions May 1996
Ethernet Networks", RFC 894, Symbolics, April 1984. Ethernet Networks", RFC 894, Symbolics, April 1984.
[16] Postel, J. and J. Reynolds, "Standard for the Transmission of [16] Postel, J. and J. Reynolds, "Standard for the Transmission of
IP Datagrams Over IEEE 802 Networks", RFC 1042, USC/Information IP Datagrams Over IEEE 802 Networks", RFC 1042, USC/Information
Sciences Institute, February 1988. Sciences Institute, February 1988.
[17] Sun Microsystems, "System and Network Administration", March [17] Sun Microsystems, "System and Network Administration", March
1990. 1990.
[18] Mills, D., "Internet Time Synchronization: The Network Time [18] Mills, D., "Internet Time Synchronization: The Network Time
skipping to change at page 38, line 42 skipping to change at page 38, line 4
13. Security Considerations 13. Security Considerations
Security issues are not discussed in this memo. Security issues are not discussed in this memo.
14. Authors' Addresses 14. Authors' Addresses
Steve Alexander Steve Alexander
Silicon Graphics, Inc. Silicon Graphics, Inc.
2011 N. Shoreline Boulevard 2011 N. Shoreline Boulevard
DRAFT DHCP Options and BOOTP Vendor Extensions November 1996
Mailstop 510 Mailstop 510
Mountain View, CA 94043-1389 Mountain View, CA 94043-1389
Phone: (415) 933-6172 Phone: (415) 933-6172
EMail: sca@engr.sgi.com EMail: sca@engr.sgi.com
Ralph Droms Ralph Droms
Bucknell University Bucknell University
Lewisburg, PA 17837 Lewisburg, PA 17837
 End of changes. 

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