Top 10 Most Asked DHCP Interview Questions and Answers

We go for interviews every now and then and a little practice and preparation always pay off. So,

• Are you preparing for a job interview related to microprocessors?
• Are you looking for DHCP interview questions?

If your answer to these questions is "YES", then you are at the right place. We have curated a list of the top most asked DHCP Interview questions and answers to help all the budding network engineers. These interview questions are selected by some of the most experienced interviewers and networking industry experts. We hope you get to succeed in your interview with these DHCP interview questions. 

DHCP Interview Questions and Answers

Here are the most asked and must-know DHCP interview questions and answers:

Question 1 – Explain DHCP. 

Answer – DHCP stands for Dynamic Host Configuration Protocol. It is a network protocol that assigns an IP address to hosts dynamically. It makes administration simpler and functions effectively in both very small and extremely big network setups. Any piece of hardware, even a Cisco router, can function as a DHCP server. 

Question 2 – How do DHCP works? 

Answer - DHCP works on the DORA Process (DISCOVER – OFFER – REQUEST - ACKNOWLEDGEMENT).  

• Discover: The client discovers the DHCP  
• Offer: The client is offered some IPs to choose from by DHCP  
• Request: After selecting an IP, the client requests DHCP to confirm it  
• Acknowledgement: A confirmation is sent by DHCP by sending a DHCP pack to the client. 

Check out DHCP Configuration in this video by PyNet Labs.

Question 3 - What information can a DHCP provide to the Host? 

Answer - A DHCP server can provide the following information: - 

• IP address 
• Subnet mask 
• Default gateway 
• Domain Name Server 
• WINS information 

Question 4 - What is the purpose of a DHCP relay agent? 

Answer - Any computer that passes DHCP packets between clients and servers when they are not on the same physical subnet is known as a DHCP relay agent. When clients and servers are not on the same physical subnet, relay agents are used to forwarding requests and responses. 

Question 5 - What is the DHCP decline message? 

Answer – The client notifies the server via a DHCP decline message that the network address is already in use (already assigned to another device). 

Question 6 – Can DHCP prevent unauthorized laptops from using a network that uses DHCP for dynamic addressing? 

Answer – No, DHCP is not capable of distinguishing between a permanent MAC address and the address by the user. So, it cannot stop unauthorized access to a network and cannot control the IP addresses used by users.

Question 7 – What is an IP lease? 

Answer – DHCP provides an IP to a client for eight days only. After eight days, that IP is taken from the client, and they have to ask for new IP from DHCP. This is known as an IP lease.

Question 8 - Explain different types of scopes in Windows DHCP. 

Answer: There are 3 types of scopes in windows DHCP: 

1. Normal Scope — It allows subnet masks, exclusions, reservations and A, B, and C Class IP address ranges. The condition for normal scope is that it should be defined in its subnet. 

2. Multicast Scope — Multicast Scope is used to assign IP address ranges to Class D networks. It doesn't have subnet masks, reservations, and TCP/IP parameters.

3. Superscope – A superscope is simply the collection of scopes which are combined and are able to be turned on or disabled as an individual unit.

Question 9 – What are the benefits of using DHCP? 

Answer – There are many benefits of using DHCP for both users and industry professionals. Here are the top benefits of using DHCP: 

• It creates safe and reliable configurations
• Lesser configuration errors
• Unique address to all new devices, so there are no address conflicts
• DHCPs are automatic, so it requires low network administration
• DHCP has the capability to update itself
• The administrator can add additional DHCP option types

Question 10 – Explain integration between DHCP and DNS. 

Answer – The domain name resolution for network resources is provided by DNS servers, which also links a client's DHCP-assigned TCP/IP address to its fully qualified domain name. 

The DHCP and DNS servers used to be configured and managed at different times. So, if an administrator has to change the authorization right for one user on a group of devices, they have to reach both one by one and make the required configuration changes. 

Integrating DHCP and DNS allows gathering all these tasks across various devices as one. It enables enterprise networks to scale up with the number of users, devices, or policies while reducing manual operations and costs. This integration also provides operational efficiencies. 

If the DHCP server modifies a client's IP address, the DHCP protocol does not automatically update DNS. Servers using Windows Server(r) 2008 and DHCP and clients running DHCP can register with DNS, enabling collaboration between the two to facilitate this interaction. Name-to-address relationships for the computer are synchronized when DHCP updates IP address information. 

These are our top 10 DHCP interview questions and answers. Learning all these questions will definitely help you in your interview preparation. We hope you like these questions and wish you all the best for your interview. Please do comment in the comment box below to share your valuable feedback.

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FAQs 

Question – What are the 4 phases of a DHCP request? 

Answer – The 4 phases of a DHCP request are known as DORA, which stands for Discovery, Offer, Request, and Acknowledgement. The server discovery takes place in the first stage, and in the second stage, the IP lease is offered. In the third stage, the IP lease request is sent, and in the last stage, the IP lease request is acknowledged by the server, which completes the DHCP request process. 

Question – What is the main purpose of DHCP? 

Answer – The main purpose of DHCP (Dynamic Host Configuration Protocol) is to allow the configuration of network devices on an IP network so that they can communicate. A DHCP client obtains configuration data from a DHCP server via the DHCP protocol, such as an IP address, a default route, and one or more DNS server addresses. 

Question – What are the 3 benefits of using DHCP? 

Answer – Here are the top 3 benefits of using DHCP: 

• Lesser configuration errors 
• No address conflicts 
• Reduced network configuration 

Question – Is DHCP UDP or TCP? 

Answer - A connectionless service paradigm is used by DHCP, which makes use of the User Datagram Protocol (UDP). For its activities, which are the same as those of the BOOTP protocol, it is implemented using two UDP port numbers. So, the answers to, is DHCP UDP or TCP, is UDP.