Just as honeypots are weapons against spammers, honeypot detection systems are spammer-employed counter-weapons. Honey nets and honeypots are usually implemented as parts of larger network intrusion detection systems. Client Honeypots are active security devices in search of malicious servers that attack clients. Low-interaction honeypots simulate only the services frequently requested by attackers. They give less information about the attacks or attackers than research honeypots. See honeypots in espionage fiction for fictional examples. High interaction client honeypots are very effective at detecting unknown attacks on clients. By employing virtual machines, multiple honeypots can be hosted on a single physical machine. Normally, production honeypots are low-interaction honeypots, which are easier to deploy. This in itself is indicative of the power of honeypots as anti-spam tools. There's also an advantage in having some easy-to-detect honeypots deployed. High interaction client honeypots are fully functional systems comparable to real systems with real clients. There are several terms that are used to describe client honeypots. A "honey farm" is a centralized collection of honeypots and analysis tools. Capture differs from existing client honeypots in various ways.