An e-mail relay provides message filtering services to an e-mail network. The e-mail relay monitors incoming communication and intercepts e-mail messages. The e-mail relay compares attributes of the messages to data derived from SPAM messages, which are stored in a SPAM database. The e-mail relay restricts the delivery of messages based on the comparison such as by restricting the delivery of messages having attributes close to those of SPAM messages from the SPAM database. The SPAM database is constructed by responding to user or administrator indications as to whether received messages are SPAM messages.