1. A non-transitory machine-readable medium carrying one or more sequences of instructions which, when executed by one or more processors, cause the one or more processors to carry out the steps of: receiving a message using an on-demand database service, on behalf of an entity: applying, to the message received on behalf of the entity, a security criterion retrieved from a portion of an on-demand database limited to information of the entity, where the security criterion includes validation of an address of a sender of the message; and retrieving a rule for processing the message received on behalf of the entity if the message received on behalf of the entity successfully meets the security criterion, wherein the rule is linked to the address of the sender of the message such that the rule is identified for retrieval using the validated address of the sender of the message.