Bayesian analysis filter

IMPORTANT: Don't judge GFI MailEssentials' spam detection rate until you have allowed the Bayesian filter to run for at least 1 week! GFI MailEssentials can achieve the highest detection rate compared to other anti-spam solutions because it adapts specifically to your mail. Be patient and wait at least a week before you judge it!

The Bayesian analysis filter is an adaptive, `artificial intelligence' technique that is much harder to circumvent by spammers. The Bayesian filter takes into account signatures of the latest spam mail, as well as legitimate mail sent by your company. This results in a much higher spam detection rate with much lower number of false positives. For more information about the Bayesian analysis filter, please see the Introduction chapter.

When you first install GFI MailEssentials, the Bayesian filter will be disabled. You can only enable the Bayesian filter after it has learnt your e-mail profile and stored this in the Bayesian Spam profile (bsp file). This Bayesian Spam Profile file can be created in 2 ways:

1. Automatically. GFI MailEssentials will collect legitimate mail (HAM) by scanning outbound mail. Instead of collecting SPAM, the default SPAM profile will be used that ships with GFI MailEssentials. Normally you can enable the Bayesian analysis filter after GFI MailEssentials has been running for a few days.

2. Alternatively you can run the Bayesian analysis wizard. This wizard will allow you to identify a source of SPAM (Use the default SPAM signatures provided or specify a folder with spam) and of HAM mail (for example sent items) and will then create a Bayesian Spam Profile file.

The second option requires slightly more work, but enables you to start using the bayesian filter right away, and also allows you to fine tune the Bayesian filter.

Configuring the Bayesian filter

By default the Bayesian filter is switched off but will learn automatically from outbound mails. That means you can enable it after a few days. To configure the Bayesian filter:

1. In the GFI MailEssentials configuration, select the Anti Spam > Bayesian filter node, right-click and select properties. This brings up the Bayesian filter properties. Select `Enable Bayesian analysis'.

Automatically learn from outbound e-mails: This option will continously update the legitimate mail database with outbound mails.

Download Anti Spam database: This option allows you to regularly update the default SPAM profile used by downloading the latest spam database from the GFI website.

Actions

After you have configured the Bayesian filter, you can configure what you wish to do with mail marked as Spam. Please see the actions paragraph for more information on the actions tab.