Anti-Spam control

The anti-spam system filters spam messages using dynamic evaluation email data during email reception.

Important: ESET Mail Security 4.0.x and below uses a different anti-spam module than version 4.5.x and later. We strongly recommend that you upgrade to the most recent version of ESET Mail Security for the best anti-spam protection.

To eliminate spam, ESET Mail Security uses the anti-spam control mechanism. This mechanism can be enabled using the ‘action_as’ parameter. For a full description of this parameter, refer to the esets.cfg(5) man page. Note that anti-spam scanning can only be used for email. For this reason, this functionality is only relevant for the following modules: esets_imap, esets_mda, esets_pipe, esets_pop3, esets_smtp, esets_smfi and esets_cgp.

Regular updates of the anti-spam database included in ESET Mail Security updates.

To configure anti-spam settings in ESET Mail Security:

navigate to the [global] section of the ESETS configuration file, which also contains detailed description of all available parameters

navigate to Configuration > Global > Antispam options in ESET Mail Security web interface.

We recommend that you customize the following parameters:


Several IP addresses, especially from your company, can be excluded from anti-spam scanning. This is useful to conserve system resources on the ESETS server, or eliminate false spam reports triggered by company emails.

IP addresses can be specified in the following formats:

IP (e.g.
IP/netmask (e.g.
StartingIP-EndingIP (e.g.

Default value: empty


To extend analysis of email messages for spam, you can query for other anti-spam services.

For example, you can query the Spamhaus server:

as_rbl_service = ""


Allows you to specify a document size; documents smaller than this size will not be scanned by anti-spam. We do not recommend setting this value below 100kB, as it may negatively affect classification and performance of the ESETS server.

Default value: unlimited