It's a fake system that appears to be real and logs traffic.
You think that you are attacking a system, but it really doesn't get you anywhere because the whole system was fake.
http://en.wikipedia.org/wiki/Honeypot_(computing)
In computer terminology, a honeypot is a trap set to detect, deflect, or in some manner counteract attempts at unauthorized use of information systems. Generally it consists of a computer, data, or a network site that appears to be part of a network but which is actually isolated, (un)protected, and monitored, and which seems to contain information or a resource that would be of value to attackers.