300-440 Question 240
Single answerA network administrator is tasked with configuring DHCP services for a large enterprise network. The network uses multiple VLANs, and DHCP traffic needs to traverse Layer 3 boundaries. Which solution should the administrator implement to ensure that DHCP requests from clients in different VLANs are properly forwarded to the central DHCP server?
- A
Configure DHCP snooping on all Layer 2 switches.
- B
Enable DHCP relay (IP helper) on the Layer 3 interfaces.
- C
Deploy a separate DHCP server for each VLAN.
- D
Use DHCP option 82 to provide relay capabilities.
Show answer and explanation
Correct answer: B
Explanation
In enterprise networks with multiple VLANs, DHCP requests from clients in one VLAN need to be forwarded to a central DHCP server, which typically resides in a different network segment. Using DHCP relay (IP helper) on the Layer 3 interfaces ensures that these requests are properly forwarded to the DHCP server, making it the most efficient and scalable solution.
- A. Incorrect.
DHCP snooping is a security feature that helps protect against rogue DHCP servers but does not forward DHCP requests across Layer 3 boundaries.
- B. Correct.
Enabling DHCP relay (IP helper) on the Layer 3 interfaces ensures that DHCP requests are forwarded to the central DHCP server, even when they originate from different VLANs.
- C. Incorrect.
Deploying multiple DHCP servers for each VLAN is operationally inefficient and unnecessary when a central DHCP server can be used with a relay mechanism.
- D. Incorrect.
DHCP option 82 is used to provide additional information about the DHCP client's location but does not inherently forward DHCP requests across Layer 3 boundaries.