Dynamic Host Configuration Protocol
RFC 2131
Document | Type |
RFC - Draft Standard
(March 1997; Errata)
Obsoletes RFC 1541
Was draft-ietf-dhc-dhcp (dhc WG)
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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 hostShow full document text