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
Using the CLI to Manage Message Filters
The first prompt determines whether or not a message header’s encoding should be changed to match
that of the message body if the header is changed (via a filter, for example).
The second prompt controls whether or not the appliance should impose the encoding of the message
body on the header if the header is not properly tagged with a character set.
The third prompt is used to configure how disclaimer stamping (and multiple encodings) in the message
body works. Please see “Disclaimer Stamping and Multiple Encodings” in the “Text Resources” chapter
for more information.
Sample Message Filters
In the following example, the filter command is used to create three new filters:
• The first filter is named big_messages. It uses the body-size rule to drop messages larger than 10
megabytes.
• The second filter is named no_mp3s. It uses the attachment-filename rule to drop messages that
contain attachments with the filename extension of
.mp3.
• The third filter is named mailfrompm. It uses mail-from rule examines all mail from
[e-mail] and blind-carbon copies [e-mail].
Using the
filter -> list subcommand, the filters are listed to confirm that they are active and valid,
and then the first and last filters are switched in position using the
move subcommand. Finally, the
changes are committed so that the filters take effect.
- SETUP - Configure multi-lingual settings.
mail3.example.com> filters
Choose the operation you want to perform:
- NEW - Create a new filter.
- IMPORT - Import a filter script from a file.
[]> new
Enter filter script. Enter '.' on its own line to end.
big_messages:
if (body-size >= 10M) {
drop();
}
.