Greylisting
From Hostek.com Wiki
Greylisting
Greylisting is a great way to help reduce spam.
- This feature essentially bounces all unknown messages back to the sending server. All legitimate mail server will then re-send the message in 15 minutes or less generally. This slight delay is only for the first email from the sender. On their next email to you, it will be delivered without the delay.Emails from Trusted Senders will automatically bypass Greylisting and are delivered directly to the Spool.
- The premise is that SPAMMERs create scripts that bombard your server with email s. These messages are then bounced back to their sending email server. Since, most Spammers email is not coming from a valid email server, the messages are not retried and therefore this reduces the amount of SPAM that your customer receive.
- For those messages that are returned to valid email servers, the messages will be retried at least four times. If the first retry is beyond the Block period (default 15 minutes) and within the Pass Period (default 6 hours) the message is passed to the Spool and it goes through its normal processing. A record is also created that says this is a valid email address and keeps it for 36 days (default). If another email from the same email address is received within the 36 day, record clock is reset for an additional 36 days and delivered directly to the Spool.
If you would like to disable this feature you can do this by following these steps:
- Log into SmarterMail as an administrator
- Click "Settings" at the left
- Click "Users"
- Right-click the user, and click "Edit"
- Check the box for "Disable greylisting"