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
The 
encrypted
 rule is similar to the 
true
 rule in that it takes no parameters and cannot be compared. 
This rule returns 
true
 if encrypted data is found and 
false
 if no encrypted data is found. Because this 
function requires the message to be scanned, it uses the scanning settings you define on the Scan 
Behavior page or using the 
scanconfig
 command. For more information about configuring these 
options, see 
The following filter checks all email sent through the listener, and if a message contains encrypted data, 
the message is blind-carbon-copied to the legal department and then bounced: 
Attachment Type Rule
The 
attachment-type
 rule checks the MIME types of each attachment in a message to see if it matches 
the given pattern. The pattern must be of the same form used in the Scan Behavior page or the 
scanconfig
 command, as described in 
, and so may have either 
side of the slash (
/
) replaced by an asterisk as a wildcard. If the message contains an attachment that 
matches this specified MIME type, this rule returns “true.”
Because this function requires the message to be scanned, it obeys all of the options described in 
See 
 for more information on message filter rules you can use to 
manipulate attachments to messages.
The following filter checks all email sent through the listener, and if a message contains an attachment 
with a MIME type of 
video/*
, the message is bounced:
Attachment Filename Rule
The 
attachment-filename
 rule checks the filenames of each attachment in a message to see if it matches 
the given regular expression. This comparison is case-sensitive. The comparison is, however sensitive to 
whitespace so if the filename has encoded whitespace at the end, the filter will skip the attachment. If 
one of the message’s attachments matches the filename, this rule returns “true.”
Please note the following points: 
Each attachment’s filename is captured from the MIME headers. The filename in the MIME header 
may contain trailing spaces.
prevent_encrypted_data:  
    if (encrypted) {
         bcc ('legaldept@example.domain');
         bounce();
      }
bounce_video_clips:
   if (attachment-type == 'video/*') {
        bounce();
   }