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ProSecure Web/Email Security Threat Management Appliance STM150 Reference Manual
Customizing Scans 4-7
v1.1, March 2009
For IMAP and POP3, select either Block attachment & log or No Log.
Protecting Against Email Spam
The STM150 integrates multiple anti-spam technologies to provide comprehensive protection
against unwanted mail. You can enable all or a combination of these anti-spam technologies. The
STM150 implements these spam prevention technologies in the following order:
1. Whitelist.
2. Blacklist.
3. Real-time blacklist.
4. Heuristic scanning.
This order of implementation ensures the optimum balance between spam prevention and system
performance. For example, if a mail is originating from a whitelisted source, the STM150 will
deliver the mail immediately to its destination inbox without implementing the other spam
prevention technologies, thereby speeding up mail delivery and conserving the STM150 system
resources. However, regardless of whether or not an email is whitelisted here, it will still be
scanned by the STM150’s anti-malware engines.
You can configure these anti-spam options in conjunction with content filtering to optimize
blocking of unwanted mails.
Setting Up the Whitelist and Blacklist
You can define mails that will be accepted or blocked based on the originating IP address, domain,
and email address by setting up the whitelist and blacklist. You can also define mails that will be
accepted based on the destination domain and email address.
The whitelist ensures that mail from listed (trusted) sources and recipients are not mistakenly
tagged as spam. Mails going to and from these sources and recipients are delivered to their
destinations immediately, without being scanned by the anti-spam engines. This can help speed up
the system and network performance. The blacklist, on the other hand, lists sources from which all
mail messages will be blocked You can enter up to 200 comma separated entries per list..
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 will not be scanned by
the anti-spam engines.