Implementing Cisco IP Switched Networks (CCNP SWITCH, legacy) — Question 109

A DHCP configured router is connected directly to a switch that has been provisioned with DHCP snooping. IP Source Guard with the ip verify source port-security command is configured under the interfaces that connect to all DHCP clients on the switch. However, clients are not receiving an IP address via the DHCP server.
Which option is the cause of this issue?

Answer options

• A. The DHCP server does not support information option 82.
• B. The DHCP client interfaces have storm control configured.
• C. Static DHCP bindings are not configured on the switch.
• D. DHCP snooping must be enabled on all VLANs, even if they are not utilized for dynamic address allocation.

Correct answer: A

Explanation

The correct answer is A because if the DHCP server doesn't support option 82, it cannot process the relay agent information added by the switch. Option B is incorrect since storm control does not affect DHCP communication directly. Option C is not the cause since static bindings are not mandatory for DHCP to function. Option D is also incorrect because DHCP snooping only needs to be enabled on VLANs actively used for DHCP traffic.