Block rogue DHCP server(s)
Networks often have publicly available ports that may need to be protected from unintentional or malicious activity, including the connection of un-wanted DHCP servers. Easily block or whitelist only permitted DHCP servers in your network by MAC address.
Blocking DHCP by MAC address will deny DHCP (bootp) packets for all subnets as this will be done at Layer 2. Be careful about blocking the DHCP server that has issued an IP lease to your switch(es). It is recommended that you statically assign an IP address to each of your switches to prevent unintentional outages. See uplink configuration