When Dynamic Host Configuration Protocol (DHCP) snooping is enabled on a FortiSwitch VLAN, which two...

According to theFortiSwitchOS 7.6 Administration Guideand theFortiLink 7.6 Study Guide, DHCP snooping is a security feature that prevents rogue DHCP servers from distributing incorrect IP addresses on a network. Once enabled for a specific VLAN, the switch differentiates betweentrustedanduntrustedports to regulate DHCP traffic.

Trusted Ports and DHCP Replies (Option A):In a managed FortiSwitch environment, all ports areuntrusted by default. To allow a DHCP server (such as a FortiGate or an external server) to provide IP addresses, the administrator must explicitly set the connecting port astrusted. DHCP snooping validates incoming packets; it allowsDHCP server messages(such as DHCPOFFER and DHCPACK) only on these trusted ports. Any DHCP server reply arriving on an untrusted port is identified as coming from a potentially rogue source and is discarded by the switch.

Option 82 Data Insertion (Option C):FortiSwitch supportsDHCP Option 82(also known as the Relay Information Option), which provides additional security by appending location-specific information (such as the Circuit ID and Remote ID) toDHCP request packets. When DHCP snooping is active, the switch can be configured to insert this data into client requests as they enter untrusted ports. This allows the upstream DHCP server to identify the specific physical port or VLAN from which the request originated, even if the server is located in a different subnet.

Regarding the incorrect options:Option Bis false as DHCP snooping only inspects and filters DHCP-specific traffic, not general unicast data.Option Dis incorrect because DHCP requests (client-to-server) are generally permitted on all ports to ensure clients can find a server, though some configurations allow dropping requests from untrusted sources if they do not meet specific security criteria.