==== 必填信息。没有填写将不予回复 ====
- iRedMail 版本号：0.9.0
- 使用哪个数据库存储用户帐号（OpenLDAP，MySQL，PostgreSQL）：MySQL 5.5 Server
- 使用的 Linux/BSD 发行版名称及版本号：ubuntu 14.04 LTS
- 与您的问题相关的日志信息：
====

BANNED CONTENTS ALERT

Our content checker found
    banned name:
      application/octet-stream,.exe,FileZilla_3.10.3_win64-setup.exe

in email presumably from you <zhangfy@aaaaa.com>
to the following recipient:
-> lin@aaaaa.com

Our internal reference code for your message is 15389-03/r1Pqee_GYI3K

First upstream SMTP client IP address: [114.252.82.10]
According to a 'Received:' trace, the message apparently originated at:
  [114.252.82.10], lenovo-PC unknown [114.252.82.10]

Return-Path: <zhangfy@aaaaa.com>
From: "zhangfy@aaaaa.com" <zhangfy@aaaaa.com>
Message-ID: <201505071126420547297@aaaaa.com>
Subject: =?UTF-8?B?Rnc6IEZUUOS9v+eUqA==?=

Delivery of the email was stopped!

The message has been blocked because it contains a component
(as a MIME part or nested within) with declared name
or MIME type or contents type violating our access policy.

To transfer contents that may be considered risky or unwanted
by site policies, or simply too large for mailing, please consider
publishing your content on the web, and only sending an URL of the
document to the recipient.

Depending on the recipient and sender site policies, with a little
effort it might still be possible to send any contents (including
viruses) using one of the following methods:

- encrypted using pgp, gpg or other encryption methods;

- wrapped in a password-protected or scrambled container or archive
  (e.g.: zip -e, arj -g, arc g, rar -p, or other methods)

Note that if the contents is not intended to be secret, the
encryption key or password may be included in the same message
for recipient's convenience.

We are sorry for inconvenience if the contents was not malicious.

The purpose of these restrictions is to cut the most common propagation
methods used by viruses and other malware. These often exploit automatic
mechanisms and security holes in more popular mail readers (Microsoft
mail readers and browsers are a common target). By requiring an explicit
and decisive action from the recipient to decode mail, the danger of
automatic malware propagation is largely reduced

请问如何接触这个限制？