> I have a question about greylisting. > > Does greylisting **always** involve blocking upon receipt of > the SMTP envelope and not accepting the rest of the message? > > Or, can greylisting alternatively work where it **does** accept the > **entire** message (for auditing purposes, for example) and > THEN returns the temporary rejection code?
The concept is generally that you want to reduce the load on your own server, so you wouldn't want the overhead of receiving the entire message first. However, in some environments like Merak server where greylisting isn't implemented in the SMTP protocol handler, I can see it as effective to receive the entire message, and add delays and/or temporary rejections from the static filter application. I would think the effect on the sending server would be the same or even worse than rejection or delay earlier in the protocol. However, there would be more overhead on your own server too. Bret
