 |
 |
A user raised a question about MSU's anti-spam greylisting that I couldn't answer. Suppose a user on a non-compliant email system sends a message to a recipient at MSU. That message will get a "temporary" refusal from MSU and then the non-compliant server will fail to resend it, so the recipient will never receive it. But suppose the sending user sends another message (or even the same message) to the same recipient within a short time. Will MSU's system recognize this as the required "resend" and then start accepting mail from that server? I've looked at descriptions of some implementations of greylisting, and although they don't talk about this scenario it seems as though it would satisfy some of them, which apparently only look at three things, the sender's email address, the recipient's email address, and the server IP.