This program detects dhcp servers on a network with dhcpdiscover packets. It can be used for detecting rogue dhcp servers, but it's designed to be small and simple to work with scripts.
Fln Dynamic Host Control Protocol Daemon simple, fast rogue DHCP server written to win race conditions and also modifies ethernet layer addresses from broadcast to specific MAC address in order not to be seen by network administrators in switched network
Gobbler: A tool to audit DHCP networks
Includes DHCP rogue server detection, DHCP DoS, distributed spoofed port scanner using DHCP to obtain many source IP addresses, mulitple arp scans, filtered port detection, spoofed OS detection (nmap + port 0)