Please Whitelist This Site?

I know everyone hates ads. But please understand that I am providing premium content for free that takes hundreds of hours of time to research and write. I don't want to go to a pay-only model like some sites, but when more and more people block ads, I end up working for free. And I have a family to support, just like you. :)

If you like The TCP/IP Guide, please consider the download version. It's priced very economically and you can read all of it in a convenient format without ads.

If you want to use this site for free, I'd be grateful if you could add the site to the whitelist for Adblock. To do so, just open the Adblock menu and select "Disable on tcpipguide.com". Or go to the Tools menu and select "Adblock Plus Preferences...". Then click "Add Filter..." at the bottom, and add this string: "@@||tcpipguide.com^$document". Then just click OK.

Thanks for your understanding!

Sincerely, Charles Kozierok
Author and Publisher, The TCP/IP Guide


NOTE: Using software to mass-download the site degrades the server and is prohibited.
If you want to read The TCP/IP Guide offline, please consider licensing it. Thank you.

The Book is Here... and Now On Sale!

The whole site in one document for easy reference!
The TCP/IP Guide

Custom Search







Table Of Contents  The TCP/IP Guide
 9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)
      9  TCP/IP Network Configuration and Management Protocols (BOOTP, DHCP, SNMP and RMON)
           9  Host Configuration and TCP/IP Host Configuration Protocols (BOOTP and DHCP)

Previous Topic/Section
BOOTP Relay Agents (Forwarding Agents)
Previous Page
Pages in Current Topic/Section
1
Next Page
DHCP Overview, Motivation, History and Standards
Next Topic/Section

TCP/IP Dynamic Host Configuration Protocol (DHCP)

In some ways, technological advancement can be considered more a journey than a destination. When a particular technology is refined or replaced with a superior one, it's usually only a matter of time before it too is replaced with something better. And so it was with the TCP/IP Boot Protocol. While BOOTP was far more capable than the protocol it replaced (RARP), after a number of years BOOTP itself was replaced with a new TCP/IP configuration protocol: the Dynamic Host Configuration Protocol (DHCP).

Where BOOTP represented a revolutionary change from RARP, DHCP is more of an evolution of BOOTP. It was built using BOOTP as a foundation, with the same basic message format. The most significant addition in DHCP is the ability to dynamically assign addresses to clients and to centrally manage them. It is this capability that both gives DHCP its name, and makes it so powerful. DHCP today is the standard TCP/IP host configuration protocol and is used in everything from single-client home networks to enterprise-class internetworks.

In this section I describe the concepts behind DHCP and explain how it works in detail. I begin with a topic that provides an overview of the protocol, discussing its history and the standards that define it. I then have four subsections that describe DHCP concepts and operation. The first talks about the different ways DHCP can assign addresses, with a focus on dynamic addressing. The second discusses how DHCP operates, including a look at configuration parameter management and the procedures for allocating addresses and managing those allocations. The third describes DHCP messaging and illustrates the DHCP message format. The fourth gets into more of the details of DHCP clients and servers, and also looks at special features and issues with DHCP. Finally, I conclude with a topic describing how DHCP changes to support the new IP version 6.

Related Information: Since DHCP builds upon BOOTP, they have a number of things in common. For example, DHCP makes use of BOOTP relay agent functionality, and DHCP options are basically the same as BOOTP vendor information fields. Since DHCP is the more common of the two protocols, I have tried to be complete in describing the operation of these features here, highlighting especially any differences between how they work for DHCP compared to BOOTP.

However, I have avoided duplicating the history and reasoning for the existence of many of these features. Since BOOTP came first, I have placed more of the historical information in the BOOTP section. In general, if you plan to read about DHCP as well as BOOTP, I recommend reading
the section on BOOTP first. If you don't plan to read up on BOOTP, you may wish to check the topic on DHCP/BOOTP interoperability instead.


Quick navigation to subsections and regular topics in this section



Previous Topic/Section
BOOTP Relay Agents (Forwarding Agents)
Previous Page
Pages in Current Topic/Section
1
Next Page
DHCP Overview, Motivation, History and Standards
Next Topic/Section

If you find The TCP/IP Guide useful, please consider making a small Paypal donation to help the site, using one of the buttons below. You can also donate a custom amount using the far right button (not less than $1 please, or PayPal gets most/all of your money!) In lieu of a larger donation, you may wish to consider purchasing a download license of The TCP/IP Guide. Thanks for your support!
Donate $2
Donate $5
Donate $10
Donate $20
Donate $30
Donate: $



Home - Table Of Contents - Contact Us

The TCP/IP Guide (http://www.TCPIPGuide.com)
Version 3.0 - Version Date: September 20, 2005

© Copyright 2001-2005 Charles M. Kozierok. All Rights Reserved.
Not responsible for any loss resulting from the use of this site.