A system and method for providing a reputation service for use in messaging environments employs a reputation of compiled statistics, representing whether SPAM messages have previously been received from respective a selected set of identifiers for the origin of the message, in a decision making process for newly received messages. In a preferred embodiment, the set of identifiers includes the IP address, a tuple of the domain and IP address and a tuple of the user and IP address and the set of identifiers allows for a relatively fine grained set of reputation metrics to be compiled and used when making a determination of a likelihood as to whether a received message is undesired in accordance with the invention.