For all of you email security fetishists out there, I wanted to highlight one of the less headline-grabbing (but critical) features in Kerio Connect 8. In the eternal war on spam, Kerio has implemented a wide variety of technologies and techniques designed to limit the amount of unwanted email that reaches the inbox. These prophylactic measures are constantly struggling against the increasingly promiscuous spammers trying to push their unwanted advertising and exploits to the inexperienced and unprepared.

With its new greylisting service, Kerio Connect 8 further protects against spam while building a cloud database of known senders with approved access for mail delivery.

Greylisting uses a combination of identifying factors and each unknown sender has their message delayed with a fail/retry response. Since most spam servers operate under a "fire and forget" philosophy to run cost effectively based on total volume of messages sent (per Evan Harris from Puremagic Software), they will disregard the retry message and move on to the next victim. Legitimate senders will accept this standard SMTP request and retry (delays are 30 minutes by default). Once successfully received, Kerio Connect will add the approved senders to a hosted whitelist, which is populated from all Kerio Connect 8 servers globally that have enabled greylisting, that will keep future messages from being delayed.

So give Kerio Connect 8's new greylisting service a try and tell spammers, "Laters baby."

-James Gudeli