Message Gateway with Hybrid Proxy / Store-and-Forward Logic

Abstract

Described is a technology by which an email filtering service or other gateway includes hybrid proxy and store-and-forward logic. A message is initially processed with proxy logic. If the proxy logic is unable to complete filtering / scanning of a message within a timeout period, the store-and-forward logic is invoked to complete filtering / scanning of the message. The store-and-forward logic also may be invoked if a delivery attempt made by the proxy logic fails or does not complete prior to a delivery timeout period. When such a condition is met, the store-and-forward logic accepts the message, including storing the message, sending a response that indicates the message was accepted, and closing the connection over which the message was received. The store-and-forward logic may complete any scanning if not completed by the proxy logic, and takes over delivery responsibilities.

Description

technical field [0001] The present invention relates to message gateways, and more particularly to message gateways with hybrid proxy / store-and-forward logic. Background technique [0002] Senders of external clients attempting to send mail messages to the SMTP (Simple Mail Transfer Protocol) delivery system are directed to the email filtering service / server (hereinafter referred to as "filtering service") through the hosted email filtering service. Filtering services are usually implemented as SMTP relays or gateways that either accept or reject messages. For example, messages from senders known to be bad (eg, "spammers") may be rejected. If the message is accepted, it is the filtering service's responsibility to send the message to the delivery SMTP system. [0003] Filtering services scan message headers and bodies to process undesired messages differently than other messages. Typically, such filtering services use either "proxy" or "store-and-forward" semantics with r...

AI Technical Summary

Problems solved by technology

[0007] However, the disadvantages of store-and-forward semantics include that storage is expensive

Also, rejected emails need to be handled somehow, as deleting emails is against the SMTP specification, and NDR bounce notifications being sent are often mistaken for spam

Quarantined messages increase storage costs

Also, there is more delay in end-to-end delivery, and there is a risk of mail loss if the filtering service crashes or fails after the message is officially responsible but before it is delivered

Images