Before a device on a TCP/IP network can effectively communicate, it needs to know its IP address. While a conventional network host can read this information from its internal disk, some devices have no storage, and so do not have this luxury. They need help from another device on the network to provide them with an IP address and other information and/or software they need to become active IP hosts. This problem of getting a new machine up and running is commonly called bootstrapping, and to provide this capability to IP hosts, the TCP/IP Bootstrap Protocol (BOOTP) was created.
In this section I provide a fairly detailed look at the TCP/IP Bootstrap Protocol. I begin with an overview and history of the protocol and a look at the standards that define it. I then discuss the general client/server nature of BOOTP and how addressing is done in communication between the client and the server. I describe the operation of BOOTP step by step, and illustrate the format of BOOTP messages. I conclude with a description of BOOTP vendor extensions, which are used to allow the information sent in BOOTP messages to be customized, and a discussion of BOOTP relay agents, which allow the protocol to operate even when the BOOTP server and client are on different networks.
Related Information: BOOTP was the predecessor of the Dynamic Host Configuration Protocol . DHCP was built to be substantially compatible with BOOTP and so the two protocols have a fair degree of commonality. To avoid duplication, certain information has been included only in the DHCP section, with links provided from the BOOTP topics where appropriate. On the other hand, some of the historical background information behind features like vendor information extensions and relay agents, which were first developed for BOOTP and adopted by DHCP, is in this section and linked from the DHCP topics. Why structure the sections this way? DHCP is far more popular than BOOTP today, so I wanted its description to be complete, but some features only really make sense if initially explained in the context of BOOTPs operation.
If you plan to read about DHCP as well as BOOTP, I recommend reading this section first. If you don't plan to read up on DHCP, you may wish to check the topic in the DHCP topic on DHCP/BOOTP interoperability .
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