DDoS Protections for SMTP Servers

Many businesses rely on email of some form for their day to day operation. Thisis especially true for product support organizations, who are largely unable toperform their role in the company if their in boxes are flooded with maliciousemail, or if important email is delayed because of the processing of attack traffic.Simple Message Transfer Protocol (SMTP) is the Internet protocol for thetransmission of these emails. Denial of Service (DoS) attacks are deliberateattempts by an attacker to disrupt the normal operation of a service with the goalof stopping legitimate requests for the service from being processed. Thisdisruption normally takes the form of large delays in responding to requests,dropped requests, and other service interruptions.In this paper we explore the current state of research into Distributed Denial ofService (DDoS) attack detection, protection and mitigation for SMTP serversconnected to the Internet. We find that whilst there has been significant researchinto DDoS protection and detection generally, much of it is not relevant to SMTPservers. During our survey we found only two papers directly addressingdefending SMTP servers against such attacks.