email filtering

Frankly speaking, the filtering for the E-mail is not a strict one. This is because that when the content of a E-mail is too less or even blanked, the blocking of it will be no significative as the blocking action might be too late after the finding the sign of that E-mail’s out-sending.
Although this is the case, it will still be effective for the bigger E-mails, especially to those with their attachments.