dhcploc: This utility can be used to detect unauthorized DHCP server on a subnet. It displays the dhcp servers that are active on the subnet and beeps and sends out alert messages when it sees from any unauthorized dhcp servers. The usage of this tool is as given below : dhcploc [-p] [-a:"list-of-alertnames"] [-i:alertinterval] machine-ip-address [list of valid dhcp servers ip addresses] machine-ip-address - ip address of the machine where the utility is run. If the machine has multiple adapters then you need to select an adapter (and the corresponding ip address) that is connected to the subnet under test. list of valid dhcp servers - you can specify any number of authorized dhcp servers' ip addresses here. This utility will be silent if it sees any packets from these server. However it will display the packets it sees from these servers unless '-p' option is specified. -p - if this option is specified then this utility will not display the packets it sees from the specified authorized dhcp servers. -a - if this option is specified the tool sends of alert message to the list of names specified. -i - this option specifies the alert frequency in seconds. The format of the output will look like as below :