Dynamic Host Configuration Protocol (DHCP) CCNA Exam Questions

Dynamic Host Configuration Protocol is an application layer protocol that dynamically assigns IP addresses to devices.

So, what is the use of DHCP in a network?

This feature helps address devices connected to a network.

Think about a network having thousands of devices.

What do you think? Is it possible to assign static IP addresses to each device without errors?

Here Dynamic Host Configuration Protocol helps us. This protocol assigns an IP address to each device without errors and is easy to manage.

Let us check the working of DHCP in a network.

We can use the term DORA to explain the working of DHCP. It is a four-stage process.

Let us check each stage.

1. D-- DHCP Discovery

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

   
   

2. O--- DHCP Offer

   At this stage, the 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 the 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 the client accepted the IP address information.

The advantages of using Dynamic Host Configuration Protocol are:

1. Few chances of getting IP addressing errors.

   
   

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

   
   

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

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
   
   
5. TTL Expired in Transit - Reason and Solution

If you prepare for Cisco certification exams like CCNA, you must have good knowledge of DHCP.

If you follow the CCNA dump for your next exam, the dotted information might help you.

Some important points 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 a domain name to client --domain-name
  
  
• Command to specify DHCP IP range -- network
  
  
• The command to check if the server can use an IP address in the pool -ip dhcp ping timeout
  
  
• The 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 acknowledgment from the server tells the client the offer is no longer valid.
  
  
• DHCPDECLINE - The client tells the server, it cannot use the offer from the server.