Checks the message to see if it is or contains a binary and rejects it if it is. The following checks are performed: Ensure that no Content-Type header in the headers or the body contains the strings "application", "image", "audio", or "video"; ensure that no Content-Transfer-Encoding header in the headers or the body is equal to "base64", and ensure that encoded lines do not exceed 50% of the number of lines in the body for any article with at least 40 lines.
An encoded line is defined as a line beginning with an M (with optional leading whitespace or quoting characters) and exactly 60 or 61 characters in length, or a line containing no spaces, not starting with M or ~, and between 59 and 80 characters in length.
Lines meeting those criteria are counted separately (the first as potential uuencoding, the second as potential base64 encoding), and if the count of lines in any one category is over half of the total body lines, the message is rejected.
The rejection messages are:
- base64 encoded
The message contains a Content-Transfer-Encoding header with a value of "base64".
- Invalid content type
The message contains a Content-Type header that contains one of the strings "application", "image", "audio", or "video".
- Apparently uuencoded
The message body is at least 40 lines and more than 50% of those lines start with M (modulo whitespace and quoting) and are exactly 60 or 61 characters long.
- Apparently base64-encoded
The message body is at least 40 lines and more than 50% of those lines contain no spaces, do not begin with M or ~, and are between 59 and 80 characters long.
This article takes no arguments or configuration directives.