Choose the features you need and the generator writes a mimedefang-filter for you. Everything runs in your browser: nothing you enter is sent anywhere. See mimedefang-filter(5) and the snippets to customize the result further.

Test the filter before you install it. Save the download as /etc/mail/mimedefang-filter.new and run:

mimedefang.pl -f /etc/mail/mimedefang-filter.new -test

It must print Filter /etc/mail/mimedefang-filter.new seems syntactically correct. Any other output, such as a Perl syntax error or Can't locate Mail/....pm, must be fixed first; it usually means a Perl module listed under the preview is not installed. Then move the file to /etc/mail/mimedefang-filter and reload MIMEDefang. The test checks only that the filter compiles and its modules load, not that it does what you want: see mimedefang.pl(8).

Filter Generator