Greylisting is a new weapon to use against spam in this great war being waged upon it. With this new shielding method, by which you may block out huge amounts of spam, you are sure to please your email clients!
In name, as well as operation, greylisting is related to whitelisting and blacklisting. What happen is that each time a given mailbox receives an email from an unknown contact (ip), that mail is rejected with a "try again later"-message (This happens at the SMTP layer and is transparent to the end user). This, in the short run, means that all mail gets delayed at least until the sender tries again - but this is where spam loses out! Most spam is not sent out using RFC compliant MTAs; the spamming software will not try again later.
This interface allows you to configure Greylisting, a service that protects your server against unwanted email or spam. When enabled, the mail server will temporarily reject any email from a sender that the server does not recognize. If the email is legitimate, the originating server tries to send it again after a delay. After sufficient time passes, the server accepts the email.
Greylisting identifies incoming email by triplets. A triplet is a collection of three pieces of data: the IP address, the sender's address, and the recipient's address. By deferring unknown triplets, Greylisting filters spam and allows legitimate email a second chance to pass through.
If Greylisting is disabled on the server, this interface only displays an On/ Off toggle. Click the toggle to change it to On and enable Greylisting.
The Configuration Settings tab allows you to specify the Greylisting parameters.
To use Greylisting, perform the following steps:
-Click the Configuration Settings tab.
-Enter the desired values for each setting, or keep the default values.