Email Greylisting
This page allows you to enable greylisting of incoming email on your mail server, which reduces spam by forcing sending mail servers to re-try sending the first time they are seen. Real mail servers will re-try after a short delay, but those operated by spammers typically will not. Thus legitimate email still gets delivered, but spam does not.

When greylisting is enabled, this page will also show a list of client mail servers and recipient email addresses that are excluded from greylisting. You can edit one by clicking on it, or use the Add link to create a new entry. Whitelist entries can be removed by checking the boxes next to them and clicking the Delete Selected button at the bottom of the page.