draft-ietf-dhc-domsrch-00.txt   draft-ietf-dhc-domsrch-01.txt 
Network Working Group Pratik Gupta, IBM Network Working Group P. Gupta
INTERNET DRAFT Glenn Stump, IBM Internet Draft IBM Corporation
July 1997 Obsoletes: draft-ietf-dhc-domsrch-00.txt November 1998
Expires January 1998 Expires May 1999
The Domain Search Option for DHCP The Domain Search Option for DHCP
<draft-ietf-dhc-domsrch-00.txt> <draft-ietf-dhc-domsrch-01.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,
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1.0 Abstract Abstract
The Dynamic Host Configuration Protocol (DHCP) [1] provides a The Dynamic Host Configuration Protocol (DHCP) [1] provides a
framework for passing configuration information to hosts on a TCP/IP framework for passing configuration information to hosts on a TCP/IP
network. This document defines a new option which is passed form the network. This document defines a new option which is passed form the
DHCP server to the DHCP Client to configure the domain search list DHCP Server to the DHCP Client to configure the domain search list
which is used by the clients to resolve hostnames in the Domain Name which is used by the clients to resolve hostnames in the Domain Name
System. System[3].
2.0 Introduction Introduction
RFC 2132 allows the Domain Name (option 15) and the Domain Name
Server (option 6) to be passed to the DHCP client. This information
is used to resolve names in the Domain Name System. These options are
usually placed in the resolv.conf file on most operating systems. The
name resolution routines on the client are also capable of using a
domain search list that allows name resolution to be attempted in a
number of domains in sequence. The Domain Search Option allows a list
of domain names, in order of preference, to be passed to the DHCP
client such that the search directive can be specified for name
resolution.
Definitions
RFC 2132 allows the Domain Name option (option 15) and the Domain
Name Server (option 6) to be passed to the DHCP client. These
options are usually used to configure resolv.conf file on most
operating systems. This information is used to resolve names in the
Domain Name System[]. This option allowes a list of domain names in
the order of preference to be passed to the DHCP client such that the
search directive can be specified for name resolution.
3.0 Definitions
Throughout this document, the words that are used to define the Throughout this document, the words that are used to define the
significance of the particular requirements are capitalized. These significance of the particular requirements are capitalized. These
words are: words are:
MUST "MUST"
This word or the adjective "REQUIRED" means that the item is This word or the adjective "REQUIRED" means that the item is
an absolute requirement of this specification. an absolute requirement of this specification.
MUST NOT "MUST NOT"
This phrase means the item is an absolute prohibition of this This phrase means the item is an absolute prohibition of this
specification. specification.
SHOULD "SHOULD"
This word or the adjective "RECOMMENDED" means that there may This word or the adjective "RECOMMENDED" means that there may
exist valid reasons in particular circumstances to ignore exist valid reasons in particular circumstances to ignore
this item, but the full implications should be understood and this item, but the full implications should be understood and
the case carefully weighed before choosing a different the case carefully weighed before choosing a different
course. course.
SHOULD NOT "SHOULD NOT"
This phrase means that there may exist valid reasons in This phrase means that there may exist valid reasons in
particular circumstances when the listed behavior is particular circumstances when the listed behavior is
acceptable or even useful, but the full implications should acceptable or even useful, but the full implications should
be understood and the case carefully weighted before be understood and the case carefully weighted before
implementing any behavior described with this label. implementing any behavior described with this label.
MAY "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 enhances the product, for example, another vendor may omit
the same item. the same item.
This document also uses the following terms: This document also uses the following terms:
o "DHCP client" "DHCP client"
DHCP client or "client" is an Internet host using DHCP to DHCP client or "client" is an Internet host using DHCP to
obtain configuration parameters such as a network address. obtain configuration parameters such as a network address.
o "DHCP server" "DHCP server"
A DHCP server or "server" is an Internet host that returns
A DHCP server of "server"is an Internet host that returns
configuration parameters to DHCP clients. configuration parameters to DHCP clients.
3.0 Domain Search Option Format Domain Search Option Format
The code for this option is TBD, and its minimum length is 2 bytes. The code for this option is TBD, and its minimum length is 2 bytes.
Code Len Priority Code Len Domain Names in Sequence
+-------+-------+-------+--------+---------+---------+-- +-------+-------+-------+--------+---------+-
| TBD | n | d1 | 0 | d2 | 0 | | TBD | n | d1 | 0x20 | d2 |
+-------+-------+-------+--------+---------+---------+-- +-------+-------+-------+--------+---------+-
where: Where d1 & d2 are domain names specified as NVT ASCII strings. An
d1 & d2 are domain names ASCII space character (0x20) is used as a separator between the
domain names.
4.0 DHCP Client Behavior DHCP Client Behavior
If a DHCP client is given both a Domain Name Option and a Domain The DHCP client will use this option to create a domain search list
Search Option, the Domain Search Option will take precedence. for name resolution. If a DHCP client is given both a Domain Name
Option and a Domain Search Option, the Domain Search Option will
take precedence.
5.0 Security Considerations Security Considerations
DHCP currently provides no authentication or security mechanisms. DHCP currently provides no authentication or security mechanisms.
Potential exposures to attack are discussed in section 7 of the DHCP Potential exposures to attack are discussed in section 7 of the DHCP
protocol specification [1]. protocol specification [1].
6.0 References References
[RFC1533] S. Alexander, R. Droms, "DHCP Options and BOOTP Vendor
Extensions"
[RFC1541] R. Droms, "Dynamic Host Configuration Protocol"
7.0 Acknowledgments [1] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131, March
1997.
[2] Alexander, S. and Droms, R., "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997.
[3] Mockapetris, P. V., "Domain names - implementation and
specification", RFC 1035, November 1987.
8.0 Author Information Author Information
Pratik Gupta Pratik Gupta
IBM, Inc. IBM Corporation
4205 S.Miami Blvd 4205 S.Miami Blvd
Research Triangle Park, NC 27709 Research Triangle Park, NC 27709
Phone: (919)254-5654 Phone: (919)254-5654
email: pratik_gupta@vnet.ibm.com email: pratikg@us.ibm.com
Glenn Stump Expiration
IBM, Inc.
4205 S.Miami Blvd This document will expire on May 31, 1999.
Research Triangle Park, NC 27709
Phone: (919)254-5616 Full Copyright Statement
email: glennstump@vnet.ibm.com
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