Bootstrap Protocol: Difference between revisions

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{{short description|Computer networking protocol}}

The '''Bootstrap Protocol''' ('''BOOTP''') is a [[computer network]]ingnetworking protocol used in

{{IPstack}}

The '''Bootstrap Protocol''' ('''BOOTP''') is a [[computer network]]ing protocol used in

[[Internet Protocol]] networks to automatically assign an [[IP address]] to network devices from a configuration server. The BOOTP was originally defined in {{IETF RFC|951}} published in 1985.

While some parts of BOOTP have been effectively superseded by the [[Dynamic Host Configuration Protocol]] (DHCP), which adds the feature of leases, parts of BOOTP are used to provide service to the DHCP protocol. Some DHCP servers also provide the legacy BOOTP functionality.

When a network-connected computer [[booting|boots]] up, its IP stack broadcasts BOOTP network messages requesting an IP- address assignment. A BOOTP configuration- server replies to the request by assigning an IP address from a pool of addresses, which is preconfigured by an administrator.

BOOTP is implemented using the [[User Datagram Protocol]] (UDP) for transport. protocol, portPort number 67 is used by the (DHCP) server for receiving client- requests, and port number 68 is used by the client for receiving (DHCP) server responses. BOOTP operates only on [[IPv4]] networks.

Historically, BOOTP has also been used for [[Unix-like]] [[diskless workstation]]s to obtain the network ___location of their [[boot image]], in addition to the IP address assignment. Enterprises used it to roll out a pre-configured client (e.g., [[Microsoft Windows|Windows]]) installation to newly installed PCs.

Initially requiring the use of a boot [[floppy disk]] to establish the initial network connection, manufacturers of network cardsinterfaces later embedded the protocol in the [[BIOSfirmware]] of the interface cards as well as system boards with on-board network adaptersinterfaces, thus allowing direct network booting.

==History==

The BOOTP was first defined in September 1985 by Bill Croft and [[John Gilmore (activist)|John Gilmore]]{{Ref RFC|951}} as a replacement for the [[Reverse Address Resolution Protocol [[RARP]] (RARP), published in June 1984.{{Ref RFC|903}} The primary motivation for replacing RARP with BOOTP is that RARP was a [[link layer]] protocol. This made implementation difficult on many server platforms, and required that a server be present on each individual IP [[subnetwork|subnet]]. BOOTP introduced the innovation of relay agents, which forwarded BOOTP packets from the local network using standard IP routing, so that one central BOOTP server could serve hosts on many subnets.{{Ref RFC|951|rsection=6}}

An increasing set of BOOTP vendor information extensions was defined{{Ref RFC|1048}}{{Ref RFC|1084}}{{Ref RFC|1395}}{{Ref RFC|1497}} to supply BOOTP clients of relevant information about the network, like [[default gateway]], [[Domain name system|name server IP address]], the [[___domain name]], etcetera.

With the advent of the [[Dynamic Host Configuration Protocol]], the BOOTP vendor information extensions were incorporated as DHCP option fields,{{Ref RFC|1533}}{{Ref RFC|2132}} to allow DHCP servers to also serve BOOTP clients.

==Operation==

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When the client receives this information from the BOOTP server, it configures and initializes its TCP/IP protocol stack, and then connects to the server on which the boot image is shared. The client loads the boot image and uses this information to load and start its operating system.<ref>{{cite web |url=https://networkencyclopedia.com/bootstrap-protocol-bootp/ |title=Bootstrap Protocol (BOOTP) |website=Network Encyclopedia}}</ref>

The Dynamic Host Configuration Protocol (DHCP) was developed as an extension of BOOTP. BOOTP is defined in RequestRequests for Comments (RFC) 951 and 1084.

=== Case 2: Client and server on different networks ===

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==External links==

* [http://www.eventhelix.com/RealtimeMantra/Networking/Bootp.pdf BOOTP Sequence Diagram] {{Webarchive|url=https://web.archive.org/web/20150226073404/http://www.eventhelix.com/RealtimeMantra/Networking/Bootp.pdf |date=2015-02-26 }} (PDF)

* [httphttps://mbootp.sourceforge.net/ Multicast BOOTP for configuring a network device]

* [httphttps://mbootp.sourceforge.net/ Multicast BOOTP server and client]

[[Category:Internet protocols]]