A customer requests a design that ensures that client devices are not dynamically configured with incorrect DNS information, which security technology must be configured on the switches when…

DHCP snooping acts as a firewall between untrusted client-facing ports and trusted uplinks, inspecting DHCP messages and dropping responses from unauthorized sources. Because DNS server assignments are delivered via DHCP offers, blocking rogue DHCP servers directly prevents clients from receiving incorrect DNS information. This is configured on switches at Layer 2 and enforced through a binding table of legitimate leases.

DNS snooping is not a recognized Cisco or IEEE switch security feature - it does not exist as a configurable technology on network switches.

Root guard is a Spanning Tree Protocol feature that prevents an unauthorized switch from becoming the root bridge, and has no relationship to DHCP or DNS configuration.

IGMP snooping is a multicast optimization that constrains Layer 2 multicast traffic to only the ports with interested receivers, completely unrelated to IP address or DNS assignment.