User guide

Using VStream Antispam
Chapter 15: Using Antivirus and Antispam Filtering 547
Configuring the VStream Antispam Policy
VStream Antispam includes a flexible mechanism that allows the user to define exactly
which emails should be scanned for spam and which should be considered safe, by
specifying the protocol, and the source and destination IP addresses.
VStream Antispam processes policy rules in the order they appear in the Antispam Policy
table, so that rule 1 is applied before rule 2, and so on. This enables you to define
exceptions to rules, by placing the exceptions higher up in the Rules table.
For example, if you want to scan all outgoing SMTP traffic, except traffic from a specific
IP address, you can create a rule scanning all outgoing SMTP traffic and move the rule
down in the Antispam Policy table. Then create a rule passing SMTP traffic from the
desired IP address and move this rule to a higher location in the Antispam Policy table than
the first rule. In the figure below, the general rule is rule number 2, and the exception is
rule number 1.