Paps is a passively active port scanner. It scans while posing as other hosts in the same network segment and sniffs for responses in order to determine port status. It is multithreaded and supports syn, fin, null, xmas, udp and random scanning.
You can download it from the following link: https://packetstormsecurity.com/files/download/43512/paps-1.0.tar.gz
Source: https://packetstormsecurity.com/files/43512/paps-1.0.tar.gz.html