Hostmap is a free, automatic, hostnames and virtual hosts discovery tool written in Ruby and licensed under GNU General Public License version 3 (GPLv3). It’s goal is to enumerate all hostnames and configured virtual hosts on an IP address. The primary users of hostmap are professionals performing vulnerability assessments and penetration tests.
You can download it from the following link: https://packetstormsecurity.com/files/download/83982/hostmap-0.2.tar.gz
Source: https://packetstormsecurity.com/files/83982/Hostmap-Discovery-Tool-0.2.html