A honeynet is a network set up with intentional vulnerabilities; its purpose is to invite attack, so that an attacker's activities and methods can be studied and that information used to increase network security. A honeynet contains one or more honey pots, which are computer systems on the Internet expressly set up to attract and "trap" people who attempt to penetrate other people's computer systems. Although the primary purpose of a honeynet is to gather information about attackers' methods and motives, the decoy network can benefit its operator in other ways, for example by diverting attackers from a real network and its resources. The Honeynet Project, a non-profit research organization dedicated to computer security and information sharing, actively promotes the deployment of honeynets.
In addition to the honey pots, a honeynet usually has real applications and services so that it seems like a normal network and a worthwhile target. However, because the honeynet doesn't actually serve any authorized users, any attempt to contact the network from without is likely an illicit attempt to breach its security, and any outbound activity is likely evidence that a system has been compromised. For this reason, the suspect information is much more apparent than it would be in an actual network, where it would have to be found amidst all the legitimate network data. Applications within a honeynet are often given names such as "Finances" or "Human Services" to make them sound appealing to the attacker.
A virtual honeynet is one that, while appearing to be an entire network, resides on a single server.