DECENTRALIZED RATE-LIMITING OF OUTBOUND E-MAIL

摘要

Many organizations that for their nature, or for budget constraints, choose to enforce a moderate level of security, recently suffer from e-mail service disruption, caused by occasional use of their mail exchangers as spamming engines, by intruders or by unscrupulous legitimate users. These events are tied to the current trend of using blacklists as anti-spamming defence. We propose in this paper an architecture whose purpose is to offer a low cost self-protection from such disruptions, with no impact on user habits nor on outside communication. It is an alternative to rate-limiting at the SMTP server that tends to reduce internal bandwidth consumption, moving the load onto the clients.