DHCPSnoop will listen on a network interface for DHCP replies from it's own DHCP requests and any other requests it can see during the runtime.
It will then verify the DHCP response parameters that are returned against the settings in it's configuration file.
It will then verify the DHCP response parameters that are returned against the settings in it's configuration file.
more here........https://github.com/mgale/DHCPSnoop