exscan is a network/Internet port scanner. It uses the “strobe-scan” technique, which means exscan only scans for certain services, instead of scanning a range of ports.
You can download it from the following link: https://packetstormsecurity.com/files/download/14142/exscan-0.2.tgz
Source: https://packetstormsecurity.com/files/14142/exscan-0.2.tgz.html