Bootstrap Protocol (BOOTP)

Every computer connected to a TCP/IP internet must be aware of specific information, like:

• Including its IP address,
• Subnet mask,
• Router's IP address, and
• The name server's IP address.

This information is typically stored in a configuration file, this data is accessed by the computer during the bootstrap process.

The Bootstrap Protocol (BOOTP) holds a vital role in establishing network connections during a computer's boot-up. Initially dependent on floppy disks, BOOTP transitioned into integrated computer hardware, eliminating the need for external drives.

Table of Contents

• How BOOTP Works:
• BOOTP versus DHCP

BOOTP's primary function is to aid computers in obtaining crucial configurations for proper functionality post-boot. Utilizing a relay agent for packet forwarding across local networks via standard IP routing, a single BOOTP server can serve hosts on multiple subnets.

While Dynamic Host Configuration Protocol (DHCP) has largely superseded BOOTP due to added options and flexibility, BOOTP has found renewed use in diskless media center PCs.

Bootstrap Protocol (BOOTP)

Operating as a broadcast protocol, BOOTP sends messages to all available hosts in the network to gather necessary answers or resources. This broadcast nature aligns with its role during the bootstrap process when the computer initializes. Initially relying on floppy disks, the bootstrap process was later integrated into the BIOS of network interface cards and motherboards for direct network booting. BOOTP communicates through UDP ports 67 and 68.

How BOOTP Works:

Upon initiation, a BOOTP client lacks an IP address, prompting it to broadcast a " BOOTP request " containing its MAC address across the network. The BOOTP server intercepts this message and responds to the client, providing essential information, including:

• The client's IP address, subnet mask, and default gateway address
• The IP address and hostname of the BOOTP server
• The IP address of the server housing the boot image required by the client to load its operating system

Upon receiving this data from the BOOTP server, the client configures and initializes its TCP/IP protocol stack. Subsequently, it establishes a connection to the server where the boot image is shared. The client loads the boot image, utilizing this information to initiate and run its operating system.

It's noteworthy that the Dynamic Host Configuration Protocol (DHCP) evolved as an extension of BOOTP. BOOTP is detailed in Request for Comments (RFC) 951 and 1084.

 

BOOTP versus DHCP

Following are the important differences between BOOTP and DHCP.

Key	BOOTP	DHCP
Definition	Bootstrap Protocol	Dynamic Host Configuration Protocol
Temporary IP Address	No support for temporary IP addressing	Supports temporary IP addressing but for a limited period
Client Support	Does not support DHCP clients	Supports BOOTP clients
Configuration Type	Manual configuration	Automatic configuration
Mobile Machine Support	Does not support mobile machines	Supports mobile machines
Error Probability	Manual configuration often leads to errors	Automatic configuration prevents errors