Network Promiscuous Ethernet Detector, rewriten with Libnet/libpcap so it works on FreeBSD, OpenBSD, and linux, possibly more. neped scans your subnet and detects promiscuous boxes that might be running sniffers or similar applications, using hacked ARPs (non broadcast), only listened by promiscuous ethernets.
You can download it from the following link: https://packetstormsecurity.com/files/download/11181/neped-libnet.tar.gz
Source: https://packetstormsecurity.com/files/11181/neped-libnet.tar.gz.html