Cisco Cisco Email Security Appliance C160 Mode D'Emploi
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User Guide for AsyncOS 10.0 for Cisco Email Security Appliances
Chapter 9 Using Message Filters to Enforce Email Policies
Message Filter Rules
Valid Rule
The
valid
rule returns false if the message contains unparsable/invalid MIME parts and true otherwise.
For example, the following rule drops all unparsable messages it tests.
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:
alt-src-host('external');
}
not-valid-mime:
if not valid
{
drop();
}
scamFilter:
if (subject == '^Make Money')
{
drop();
}
EmptySubject_To_filter:
if (header('Subject') != ".") OR
(header('To') != ".") {
drop();
}