1. A non-transitory machine-readable medium storing computer code adapted to be executed by a computer to perform a method comprising: receiving, through a service of a system having a processor and a memory, a communication destined to a first user of a plurality of users of the service; performing, by the system, security checking of the communication by applying a plurality of security checks to the communication; receiving, from each of the plurality of security checks, a code indicative of a result of the security check; determining a return code that summarizes the received codes and indicates whether the communication passes the security checking; delivering, through the service of the system, the communication to a first location that is a destination of the communication, when the return code indicates that the communication passes the security checking; and directing, by the system, the communication to a second location specified for communications that do not pass the security checking, when the return code indicates that the communication fails the security checking.