User Guide

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AsyncOS 9.1.2 for Cisco Email Security Appliances User Guide
Chapter 9 Using Message Filters to Enforce Email Policies
Message Filter Actions
The mbox format is a standard UNIX mailbox format, and there are many utilities available to make
viewing the messages easier. Most UNIX systems allow you to type
“
mail -f mbox.filename” to view the files. The mbox format is in plain text, so you can use a simple
text editor to view the contents of the messages.
In the following example, a copy of the message is saved to a log named
joesmith if the Envelope Sender
matches
[e-mail]:
Strip Header Action
The strip-header action examines the message for a particular header and removes those lines from the
message before delivering it. When there are multiple headers, all instances of the header are removed
(for example, the “Received:” header.)
In the following example, all messages have the header
X-DeleteMe removed before transmission:
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
Message Header Rules and Evaluation, page 9-5 for more information.
Insert Header Action
The insert-header action inserts a new header into a message. AsyncOS does not verify the compliance
to standards of the header you insert; you are responsible for ensuring that the resulting message
complies with Internet standards for email.
The following example inserts a header named
X-Company with the value set to My Company Name if the
header is not already found in the message:
logJoeSmithFilter:
if(mail-from == '^joesmith@yourdomain\\.com$')
{
archive('joesmith');
}
stripXDeleteMeFilter:
if (true)
{
strip-header('X-DeleteMe');
}
addXCompanyFilter:
if (not header('X-Company'))
{