The settings made in this interface determine what kind of mails should be classified as 'spam', 'probable' and 'safe'. CASG enforces several rules to mail envelope, header and content as the emails passes through its spam filters. Each of these rules depicts some typical spam attribute, which has a numeric value on the probability that the attribute suggests spam. A message's spam score depends on the result of weighted value of all the rules combined together. For example, if you set the spam threshold as 0.33, all mails that have a score of more than 0.33 will be treated as spam and quarantined. Please note that the highest spam threshold is 1 for CASG and the higher threshold you set, it is likely that more spam messages may be delivered to the recipients. Try the settings for a week or so and after analyzing how much spam messages are being delivered to the recipients without being filtered for the current settings, you have to reconfigure the spam threshold settings accordingly.
To configure incoming spam detection settings
Click 'Incoming spam detection settings' from the 'Incoming' drop-down menu in the menu bar or the icon in the 'Incoming' configuration area.
The incoming spam detection settings area of the selected domain will open:
Quarantine enabled - Selecting this option will enable the quarantine settings that will be applied to the incoming mails and quarantined as per the spam threshold setting. If this option is not enabled, emails that are detected as 'Spam' will not be quarantined but delivered to your email server with the messages in subject line that you have set in Probable spam notation / Spam notation. The unsure messages are not quarantined and sent to the recipients even if this option is enabled.
Spam threshold - Enter any value between 0.1 and 1.0. All mails that are having a score value above that is set in this field will be quarantined automatically as explained in the introduction para of this section. Please note this value should be always higher than Unsure threshold value.
Probable spam threshold - Enter any value between 0.0 and the value entered in Spam threshold field. All mails that are having a score value above that is set in this field will be identified as unsure mails and will be delivered to recipients with the messages in subject line that you have set in the Probable spam notation / Spam notation.
Days saved - Enter the number of days that you want the mails to be quarantined. The maximum number of days that can be set is 9999. The quarantined mails that are not checked, released or deleted within the stipulated days will be deleted automatically from the quarantine.
- Probable spam notation - The prefix that will be prepended to the subject line of all ‘unsure’ emails sent to users. For example, “<Potentially Spam> Cheap deals on Dell computers” – where <Potentially Spam> is the ‘Unsure’ notation’.
- Spam notation - The prefix that will be prepended to the subject line of all ‘Spam’ emails sent to users. For example, “<Spam> Order two Rolex watches and get a free carton of Viagra” – where <Spam> is the ‘Unsure’ notation’. Note - this only applies IF quarantine has been disabled (i.e. If the ‘Quarantine Enabled’ box is not checked).
- Quarantine response – Determines the response that CASG will send to the SMTP server that delivered a message in the event that the mail is identified as spam.
- Rejected - Will inform the SMTP server that the email has been rejected by CASG and placed in quarantine.
- Accepted - The email has passed the CASG spam filters and detected as a spam will be placed in quarantine in silent mode.
- Reset to Default - Reset to default all adjusted selected domain settings.
Click the 'Save' button. The incoming spam detection settings for the selected domain will be saved.