mail/mimedefang 3.4.1nb4 NetBSD

MIMEDefang is an e-mail filter program which works with Sendmail 8.12 and later. MIMEDefang filters all e-mail messages sent via SMTP. MIMEDefang splits multi-part MIME messages into their components and potentially deletes or modifies the various parts. It then reassembles the parts back into an e-mail message and sends it on its way.

MIMEDefang is written (mostly) in Perl, and the filter actions are expressed in Perl. This makes MIMEDefang highly flexible and configurable. As a simple example, you can delete all *.exe and *.com files, convert all Word documents to HTML, and allow other attachments through.

MIMEDefang uses the "milter" feature of Sendmail to "listen in" to SMTP connections. It runs a scan once for each message, not once for each recipient (as simpler procmail-based systems do.) Therefore, it is more CPU-friendly than procmail-based systems. In addition, because MIMEDefang can participate in the SMTP connection, you can bounce messages (something impossible to do with procmail-based systems.)