mpscan is a parallel network scanner that checks for open ports. It uses select() to increase its speed and was designed for rapidly scanning large networks, but also works with a single IP.
You can download it from the following link: https://packetstormsecurity.com/files/download/43482/mpscan-0.1.0.tar.gz
Source: https://packetstormsecurity.com/files/43482/mpscan-0.1.0.tar.gz.html