Cisco Cisco Email Security Appliance C170 Guia Do Utilizador
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User Guide for AsyncOS 9.7 for Cisco Email Security Appliances
Chapter 9 Using Message Filters to Enforce Email Policies
Message Filter Rules
Subject Rule
The
subject
rule selects those messages where the value of the subject header matches the given regular
expression.
For example, the following filter discards all messages with subjects that start with the phrase
Make
Money...
You can specify non-ASCII characters to search for in the value of the header.
When working with headers, remember that the current value of the header includes changes made
during processing (such as with filter actions that add, remove, or modify message headings). See
during processing (such as with filter actions that add, remove, or modify message headings). See
for more information.
The following filter returns true if the headers are empty or if the headers are missing from the message:
Note
This filter returns true for empty Subject and To headers, but it also returns true for missing headers. If
the message does not contain the specified headers, the filter still returns true.
the message does not contain the specified headers, the filter still returns true.
Envelope Recipient Rule
The
rcpt-to
rule selects those messages where any Envelope Recipient matches the given regular
expression. For example, the following filter drops all messages sent with an email address containing
the string “scarface.”
the string “scarface.”
drop();
}
scamFilter:
if (subject == '^Make Money')
{
drop();
}
EmptySubject_To_filter:
if (header('Subject') != ".") OR
(header('To') != ".") {
drop();
}