The free version enables administrators to check incoming e-mail against popular DNS blacklists (aka real-time blacklists) at the server level as well as their own. It also includes a patented automatic whitelist management tool.
Third-party DNS blacklists are databases of known spammers from which administrators can check if a sending mail server is known or thought to send spam. Two recommended DNS blacklists supported by GFI MailEssentials 8 are http://www.ordb.org, a database maintained by ORDB.org -- a non-profit organization that stores the IP addresses of verified open SMTP relays, and www.spamhaus.org, which maintains the Spamhaus Block List -- a free, real-time, DNS-based database of IP addresses of verified spammers, spam gangs, and spam services.
When installed on Exchange Server 2000, GFI MailEssentials 8 checks incoming mail against the selected third-party blacklist. The IP of the sending mail server for each incoming message is queried against the list, similar to a DNS query. If the sending mail server is on the blacklist, the e-mail is flagged as spam and optionally forwarded to a public folder.
GFI MailEssentials also supports Exchange 5.5, Lotus Notes, and SMTP mail servers.
The other key tool included in this freeware version is an automatic whitelist management tool. Business partners are added automatically, eliminating the need for administrators to manually input approved addresses on the whitelist. According to GFI, this feature enables mail to bypass the spam filter and thus reduces false positives.
The third anti-spam feature included in the free version is the ability for Exchange administrators to create their own lists of undesirable domains and e-mail addresses from which they do not want to receive mail.
The freeware version of GFI MailEssentials for Exchange/SMTP 8 is available for download from http://www.gfi.com/downloads/downloads.asp?pid=11&lid=1. The download is a trial version of GFI MailEssentials; however, the blacklist checking and whitelist features remain active after the 60-day evaluation period.
Quick install instructions are available at http://www.gfi.com/downloads/gettingstarted.asp?pid=11&vid=67&lid=1, and the GFI MailEssentials 8 manual can be downloaded from ftp://ftp.gfi.com/manuals/mes8manual.zip.
User-to-user support is also available at http://forums.gfi.com.