Selecting Scanning Conditions for Spam

Procedure

1. Under Phishing/Social Engineering Attack/Spam on the scanning conditions selection screen for the Other rule type, select the check box next to Spam detection settings.
2. Click Spam detection settings.
   The Spam Detection Settings screen appears.
3. To enable spam scanning, select the check box next to Select a spam catch rate or specify a detection threshold.
   If you do not select this check box, IMSS will not label any messages that violate this rule as spam. You can, however, still take actions on any senders in the Blocked Senders list below.
4. Select one of the following spam catch rates or specify a detection threshold.
   • High: Catches more spam. Select a high catch rate if too much spam is getting through to your clients.
   • Medium: Catches an average amount of spam (the default selection).
   • Low: Catches less spam. Select a low catch rate if IMSS is tagging too many legitimate messages as spam.
   • Specify a detection threshold: Specify a threshold value (between 3.0 and 10.0) that represents how critically IMSS analyzes messages to determine if they are spam.

   Note A higher threshold value means that a message must be very "spam-like" for IMSS to consider it spam. This decreases the spam catch rate, but it also results in a lower number of false positives. If IMSS is tagging too many legitimate messages as spam (too many false positives), specify a higher threshold value. A lower threshold value means that a message only needs to be slightly "spam-like" for IMSS to consider it spam. This increases the spam catch rate, but it also results in a higher number of false positives. If IMSS is letting too much spam through to your clients as legitimate messages, specify a lower threshold value.

5. Click DKIM approved list to enable or disable use of the DKIM Approved List. IMSS does not scan or mark messages as spam, if the messages come from domains appearing in the DKIM approved list.
6. Select the check boxes next to any of the following lists to enable them:
   • Approved sender list: Prevents IMSS from identifying messages from senders in this list as spam.
   • Blocked sender list: Forces IMSS to identify messages from senders in this list as spam.
   • Text exemption list: Prevents IMSS from identifying messages that contains any of the text in this list as spam.

   Note For instructions on configuring the lists, see Configuring Approved and Blocked Sender Lists.

7. Click Save to continue selecting scanning conditions.