Dynamic Host Configuration Protocol (DHCP) CCNA Exam Tutorial

The Dynamic Host Configuration Protocol (DHCP) allows devices to dynamically get IP address information. It is very important in networks especially for big networks because it assigns IP addresses to each devices in the network automatically. Think about a network having thousands of devices. It is very difficult to assign static IP addresses to each devices without having errors. Here Dynamic Host Configuration Protocol helps us. This protocol assigns IP address to each device without any errors and is very easy to manage. It contains two parts, server and client.


Working of Dynamic Host Configuration Protocol

We can simply use the term DORA to explain the working of DHCP. It is a four stage process and each stage is explained below.

  1. D-- DHCP Discovery

    When a client connected to a network, it sends broadcast to discover the DHCP server. This broadcast is termed as DHCPDISCOVER.

  2. O--- DHCP Offer

    At this stage, server responds to the client DISCOVERY message and sends a DHCPOFFER unicast message. DHCPOFFER includes IP address, subnet mask, default gateway address, DNS address etc.

  3. R---- DHCP Request

    Here client sends a DHCPREQUEST message to the server.

  4. A--- DHCP Acknowledgment

    Here server sends an acknowledgment (DHCPACK) to the client indicating it received the DHCPREQUEST from the client and client accepted the IP address information.

Advantages of Using DHCP

Major advantages of using Dynamic Host Configuration Protocol are:
  1. Very less chances to get IP addressing errors

  2. Efficient control on IP addressing in a network because it is centralized.

  3. We can avoid the heavy work of manual IP addressing

Suggested Topics
  1. How to Configure a Computer to Receive Automatic IP Address

  2. Interior Gateway Routing Protocol (IGRP)

  3. Internet Group Management Protocol (IGMP) Tutorial

  4. Working Of Remote Procedure Call (RPC)in Session Layer

Cisco Certification Exam Tips

If you are preparing for Cisco certification exams like CCNA, you must have good knowledge in DHCP. If you follow CCNA dump for your next exam, the dotted information might help you. Some important points to remember about Dynamic Host Configuration Protocol for your Cisco Certification exams are listed below.
  • Command to Enable or Disable DHCP on Cisco IOS Router --service dhcp

  • Cisco Command to create address pool -- ip dhcp pool

  • Command to assign domain name to client --domain-name

  • Command to specify DHCP IP range -- network

  • Command to check if server can use an IP address in the pool -ip dhcp ping timeout

  • Command to exclude an IP address from the DHCP address pool --ip dhcp excluded-address

  • Show addresses assigned to clients --show ip dhcp binding

  • DHCPNACK - This acknowledgement from server tells the client the offer is no longer valid

  • DHCPDECLINE - Client tells the server, it cannot use the offer from the server

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