Fortinet FortiGate FortiGate-5020, Руководство администратора

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Spam filter MIME headers
FortiGate-5000 series Administration Guide 01-28008-0013-20050204
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Figure 183:Adding an email address
3 Enter the email address or pattern you want to add.
4 Select a pattern type for the list entry.
5 If required, select before or after another email address in the list to place the new
email address in the correct position.
6 Select the action to take on email from the configured address or domain.
7 Select OK.
MIME headers
MIME (Multipurpose Internet Mail Extensions) headers are added to email to describe
content type and content encoding, such as the type of text in the email body or the
program that generated the email. Some examples of MIME headers include:
• X-mailer: outgluck
• X-Distribution: bulk
• Content_Type: text/html
• Content_Type: image/jpg
The first part of the MIME header is called the header key, or just header. The second
part is called the value. Spammers will often insert comments into header values or
leave them blank. These malformed headers can fool some spam and virus filters.
You can use the MIME headers list to mark email from certain bulk mail programs or
with certain types of content that are common in spam messages. You can choose to
mark the email as spam or clear for each header you configure.
The FortiGate unit compares the MIME header key-value pair of incoming email to the
list pair in sequence. If a match is found, the corresponding protection profile action is
taken. If no match is found, the email is passed on to the next spam filter.
You can use Perl regular expressions or wildcards to add MIME header patterns to the
list. See
“Using Perl regular expressions” on page 347 .
Note: MIME header entries are case sensitive.