Honeyd
Small daemon that creates virtual hosts and simulates services and OS personalities for network deception.
Honeyd is a small open-source daemon that creates virtual hosts on a network which can be configured to run arbitrary services and adapt their personality to appear as specific operating systems. A single Honeyd host can claim many addresses (the project author has tested up to 65,536) to enable large-scale network simulation. Honeyd is released under the GNU General Public License, is maintained and developed by the project author, and is used commercially by many companies. The project page links to source code, bug reporting, and related documentation; the published book "Virtual Honeypots" includes two chapters on Honeyd with additional implementation and detection details.

