Dynamic Host Configuration Protocol
RFC 2131
| Document | Type |
RFC - Draft Standard
(March 1997; Errata)
Obsoletes RFC 1541
Was draft-ietf-dhc-dhcp (dhc WG)
|
|
|---|---|---|---|
| Author | Ralph Droms | ||
| Last updated | 2020-01-21 | ||
| Stream | IETF | ||
| Formats | plain text html pdf htmlized with errata bibtex | ||
| Stream | WG state | (None) | |
| Document shepherd | No shepherd assigned | ||
| IESG | IESG state | RFC 2131 (Draft Standard) | |
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | (None) | ||
| Send notices to | (None) | ||
Network Working Group R. Droms
Request for Comments: 2131 Bucknell University
Obsoletes: 1541 March 1997
Category: Standards Track
Dynamic Host Configuration Protocol
Status of this memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Abstract
The Dynamic Host Configuration Protocol (DHCP) provides a framework
for passing configuration information to hosts on a TCPIP network.
DHCP is based on the Bootstrap Protocol (BOOTP) [7], adding the
capability of automatic allocation of reusable network addresses and
additional configuration options [19]. DHCP captures the behavior of
BOOTP relay agents [7, 21], and DHCP participants can interoperate
with BOOTP participants [9].
Table of Contents
1. Introduction. . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1 Changes to RFC1541. . . . . . . . . . . . . . . . . . . . . . 3
1.2 Related Work. . . . . . . . . . . . . . . . . . . . . . . . . 4
1.3 Problem definition and issues . . . . . . . . . . . . . . . . 4
1.4 Requirements. . . . . . . . . . . . . . . . . . . . . . . . . 5
1.5 Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.6 Design goals. . . . . . . . . . . . . . . . . . . . . . . . . 6
2. Protocol Summary. . . . . . . . . . . . . . . . . . . . . . . 8
2.1 Configuration parameters repository . . . . . . . . . . . . . 11
2.2 Dynamic allocation of network addresses . . . . . . . . . . . 12
3. The Client-Server Protocol. . . . . . . . . . . . . . . . . . 13
3.1 Client-server interaction - allocating a network address. . . 13
3.2 Client-server interaction - reusing a previously allocated
network address . . . . . . . . . . . . . . . . . . . . . . . 17
3.3 Interpretation and representation of time values. . . . . . . 20
3.4 Obtaining parameters with externally configured network
address . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.5 Client parameters in DHCP . . . . . . . . . . . . . . . . . . 21
3.6 Use of DHCP in clients with multiple interfaces . . . . . . . 22
3.7 When clients should use DHCP. . . . . . . . . . . . . . . . . 22
4. Specification of the DHCP client-server protocol. . . . . . . 22
Droms Standards Track [Page 1]
RFC 2131 Dynamic Host Configuration Protocol March 1997
4.1 Constructing and sending DHCP messages. . . . . . . . . . . . 22
4.2 DHCP server administrative controls . . . . . . . . . . . . . 25
4.3 DHCP server behavior. . . . . . . . . . . . . . . . . . . . . 26
4.4 DHCP client behavior. . . . . . . . . . . . . . . . . . . . . 34
5. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . .42
6. References . . . . . . . . . . . . . . . . . . . . . . . . . .42
7. Security Considerations. . . . . . . . . . . . . . . . . . . .43
8. Author's Address . . . . . . . . . . . . . . . . . . . . . . .44
A. Host Configuration Parameters . . . . . . . . . . . . . . . .45
List of Figures
1. Format of a DHCP message . . . . . . . . . . . . . . . . . . . 9
2. Format of the 'flags' field. . . . . . . . . . . . . . . . . . 11
3. Timeline diagram of messages exchanged between DHCP client and
servers when allocating a new network address. . . . . . . . . 15
4. Timeline diagram of messages exchanged between DHCP client and
servers when reusing a previously allocated network address. . 18
5. State-transition diagram for DHCP clients. . . . . . . . . . . 34
List of Tables
1. Description of fields in a DHCP message. . . . . . . . . . . . 10
2. DHCP messages. . . . . . . . . . . . . . . . . . . . . . . . . 14
3. Fields and options used by DHCP servers. . . . . . . . . . . . 28
4. Client messages from various states. . . . . . . . . . . . . . 33
5. Fields and options used by DHCP clients. . . . . . . . . . . . 37
1. Introduction
The Dynamic Host Configuration Protocol (DHCP) provides configuration
parameters to Internet hosts. DHCP consists of two components: a
protocol for delivering host-specific configuration parameters from a
DHCP server to a host and a mechanism for allocation of network
addresses to hosts.
DHCP is built on a client-server model, where designated DHCP server
hosts allocate network addresses and deliver configuration parameters
to dynamically configured hosts. Throughout the remainder of this
document, the term "server" refers to a host providing initialization
parameters through DHCP, and the term "client" refers to a host
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