Honeyd is a small daemon that creates virtual hosts on a network. The hosts can be configured to run arbitrary services, and their personality can be adapted so that they appear to be running certain operating systems. Honeyd enables a single host to claim multiple addresses - I have tested up to 65536 - on a LAN for network simulation. Honeyd improves cyber security by providing mechanisms for threat detection and assessment. It also deters adversaries by hiding real systems in the middle of virtual systems.
Honeyd is open source software released under GNU General Public License. Even though Honeyd is used commercially by many companies, it is being developed in my spare time without any financial support. Nontheless, I always appreciate a reduction of my wishlists, if you feel so inclined. The README in Honeyd's source distribution and the acknowledgments page lists a number of people who have contributed code and ideas.