Quick Reference Guide

98 | Chapter 4. Content Filtering and Optimizing Scans
ProSecure Web/Email Security Threat Management (STM) Appliance
This order of implementation ensures the optimum balance between spam prevention and
system performance. For example, if an email originates from a whitelisted source, the STM
delivers the email immediately to its destination inbox without implementing the other spam
prevention technologies, thereby speeding up mail delivery and conserving the STM system
resources. However, regardless of whether or not an email is whitelisted, it is still scanned by
the STM’s antimalware engines.
You can configure these antispam options in conjunction with content filtering to optimize
blocking of unwanted mails.
Note: Emails that are sent through the STM over an authenticated
connection between a client and an SMTP mail server are not
checked for spam.
Note: An email that has been checked for spam by the STM contains an
“X-STM-SMTP” (for SMTP emails) or “X-STM-POP3” (for POP-3
emails) tag in its header.
Setting Up the Whitelist and Blacklist
You can specify emails that are accepted or blocked based on the originating IP address,
domain, and email address by setting up the whitelist and blacklist. You can also specify
emails that are accepted based on the destination domain and email address.
The whitelist ensures that email from listed (that is, trusted) sources and recipients is not
mistakenly tagged as spam. Emails going to and from these sources and recipients are
delivered to their destinations immediately, without being scanned by the antispam engines.
This can help to speed up the system and network performance. The blacklist, on the other
hand, lists sources from which all email messages are blocked. You can enter up to 200
entries per list, separated by commas.
Note: The whitelist takes precedence over the blacklist, which means that
if an email source is on both the blacklist and the whitelist, the email
is not scanned by the antispam engines.