BOOTP
Encyclopedia
In computer networking, the Bootstrap Protocol, or BOOTP, is a network protocol used by a network client to obtain an IP address
from a configuration server. The BOOTP protocol was originally defined in RFC 951.
BOOTP is usually used during the bootstrap
process when a computer is starting up. A BOOTP configuration server assigns an IP address to each client from a pool of addresses. BOOTP uses the User Datagram Protocol
(UDP) as a transport on IPv4
networks only.
Historically, BOOTP has also been used for Unix-like
diskless workstation
s to obtain the network location of their boot image
in addition to an IP address, and also by enterprises to roll out a pre-configured client (e.g., Windows
) installation to newly installed PCs.
Originally requiring the use of a boot floppy disk
to establish the initial network connection, manufacturers of network cards later embedded the protocol in the BIOS
of the interface cards as well as system boards with on-board network adapters, thus allowing direct network booting.
Recently, users with an interest in diskless stand-alone media center PCs have shown new interest in this method of booting a Windows operating system.
The Dynamic Host Configuration Protocol
(DHCP) is a more advanced protocol for the same purpose and has superseded the use of BOOTP. Most DHCP servers also function as BOOTP servers.
protocol. This made implementation difficult on many server platforms, and required that a server be present on each individual IP subnet
. BOOTP introduced the innovation of a relay agent, which allowed BOOTP packets to be forwarded from the local network using standard IP routing, so that one central BOOTP server could serve hosts on many subnets.
IP address
An Internet Protocol address is a numerical label assigned to each device participating in a computer network that uses the Internet Protocol for communication. An IP address serves two principal functions: host or network interface identification and location addressing...
from a configuration server. The BOOTP protocol was originally defined in RFC 951.
BOOTP is usually used during the bootstrap
Booting
In computing, booting is a process that begins when a user turns on a computer system and prepares the computer to perform its normal operations. On modern computers, this typically involves loading and starting an operating system. The boot sequence is the initial set of operations that the...
process when a computer is starting up. A BOOTP configuration server assigns an IP address to each client from a pool of addresses. BOOTP uses the User Datagram Protocol
User Datagram Protocol
The User Datagram Protocol is one of the core members of the Internet Protocol Suite, the set of network protocols used for the Internet. With UDP, computer applications can send messages, in this case referred to as datagrams, to other hosts on an Internet Protocol network without requiring...
(UDP) as a transport on IPv4
IPv4
Internet Protocol version 4 is the fourth revision in the development of the Internet Protocol and the first version of the protocol to be widely deployed. Together with IPv6, it is at the core of standards-based internetworking methods of the Internet...
networks only.
Historically, BOOTP has also been used for Unix-like
Unix-like
A Unix-like operating system is one that behaves in a manner similar to a Unix system, while not necessarily conforming to or being certified to any version of the Single UNIX Specification....
diskless workstation
Diskless workstation
A diskless node is a workstation or personal computer without disk drives, which employs network booting to load its operating system from a server...
s to obtain the network location of their boot image
Boot image
A boot image is a type of disk image . When it is transferred onto a boot device it allows the associated hardware to boot....
in addition to an IP address, and also by enterprises to roll out a pre-configured client (e.g., Windows
Microsoft Windows
Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
) installation to newly installed PCs.
Originally requiring the use of a boot floppy disk
Floppy disk
A floppy disk is a disk storage medium composed of a disk of thin and flexible magnetic storage medium, sealed in a rectangular plastic carrier lined with fabric that removes dust particles...
to establish the initial network connection, manufacturers of network cards later embedded the protocol in the BIOS
BIOS
In IBM PC compatible computers, the basic input/output system , also known as the System BIOS or ROM BIOS , is a de facto standard defining a firmware interface....
of the interface cards as well as system boards with on-board network adapters, thus allowing direct network booting.
Recently, users with an interest in diskless stand-alone media center PCs have shown new interest in this method of booting a Windows operating system.
The Dynamic Host Configuration Protocol
Dynamic Host Configuration Protocol
The Dynamic Host Configuration Protocol is a network configuration protocol for hosts on Internet Protocol networks. Computers that are connected to IP networks must be configured before they can communicate with other hosts. The most essential information needed is an IP address, and a default...
(DHCP) is a more advanced protocol for the same purpose and has superseded the use of BOOTP. Most DHCP servers also function as BOOTP servers.
History
The BOOTP protocol was first defined in RFC 951 as a replacement for the Reverse Address Resolution Protocol RARP, published in RFC 903 in June 1984. The primary motivation for replacing RARP with BOOTP is that RARP was a data link layerData link layer
The data link layer is layer 2 of the seven-layer OSI model of computer networking. It corresponds to, or is part of the link layer of the TCP/IP reference model....
protocol. This made implementation difficult on many server platforms, and required that a server be present on each individual IP subnet
Subnetwork
A subnetwork, or subnet, is a logically visible subdivision of an IP network. The practice of dividing a network into subnetworks is called subnetting....
. BOOTP introduced the innovation of a relay agent, which allowed BOOTP packets to be forwarded from the local network using standard IP routing, so that one central BOOTP server could serve hosts on many subnets.
BOOTP Related RFCs
Note that grayed out RFCs are obsolete| RFC # | Title | Date | Obsolete and Update Information |
|---|---|---|---|
| RFC 3942 | Reclassifying Dynamic Host Configuration Protocol version 4 (DHCPv4) Options | Nov-04 | Updates RFC 2132 |
| RFC 2132 | DHCP Options and BOOTP Vendor Extensions | Mar-97 | Obsoletes RFC 1533, Updated by RFC 3442, RFC 3942, RFC 4361, RFC 4833, RFC 5494 |
| RFC 1542 | Clarifications and Extensions for the Bootstrap Protocol | Oct-93 | Obsoletes RFC 1532, Updates RFC 951 |
| RFC 1534 | Interoperation Between DHCP and BOOTP | Oct-93 | |
| RFC 1533 | DHCP Options and BOOTP Vendor Extensions | Oct-93 | Obsoletes RFC 1497, RFC 1395, RFC 1084, RFC 1048, Obsoleted by RFC 2132 |
| RFC 1532 | Clarifications and Extensions for the Bootstrap Protocol | Oct-93 | Obsoleted by RFC 1542, Updates RFC 951 |
| RFC 1497 | BOOTP Vendor Information Extensions | Aug-93 | Obsoletes RFC 1395, RFC 1084, RFC 1048, Obsoleted by RFC 1533, Updates RFC 951 |
| RFC 1395 | BOOTP Vendor Information Extensions | Jan-93 | Obsoletes RFC 1084, RFC 1048, Obsoleted by RFC 1497, RFC 1533, Updates RFC 951 |
| RFC 1084 | BOOTP vendor information extensions | Dec-88 | Obsoletes RFC 1048, Obsoleted by RFC 1395, RFC 1497, RFC 1533 |
| RFC 1048 | BOOTP vendor information extensions | Feb-88 | Obsoleted by RFC 1084, RFC 1395, RFC 1497, RFC 1533 |
| RFC 951 | Bootstrap Protocol | Sep-85 | Updated by RFC 1395, RFC 1497, RFC 1532, RFC 1542, RFC 5494 |
See also
- Preboot Execution EnvironmentPreboot Execution EnvironmentThe Preboot eXecution Environment is an environment to boot computers using a network interface independently of data storage devices or installed operating systems.PXE was introduced as part of the Wired for Management framework by Intel and is described in the specification The Preboot...
(PXE) - UDP Helper AddressUDP Helper AddressA UDP Helper Address is a special router configuration used to forward broadcast network traffic from a client machine on one subnet to a server in another subnet. This is used primarily in business environments as way to save money by not having to buy a server for each subnet.-Usage Example:In...
— a tool for routing BOOTP requests across subnet boundaries