Table of Contents
Advertisement
Content Filtering – Mail Filters
13.1 Demands
Sometimes there are malicious scripts like *.vbs that may be attached in the email. If the users accidentally open such files, their
computers may be infectious with virus.
13.2 Objectives
Modify the filename extension of the suspicious email attachments so that email receivers may notice that the file cannot be
directly opened by the operating system because of the unrecognized filename extension.
13.3 Methods
1. Setup SMTP filters for outgoing emails from PC_1 (in LAN1) towards the mail server (in DMZ1 or in WAN1) to append a
".bin" to all vbs attachments. Use PC1_1 to send an email with vbs attachments to test the configuration.
2. Setup POP3 filters for incoming emails from a mail server (in WAN1 or in DMZ1) to PC_1 (in LAN1) to append a ".bin"
to all vbs attachments. Use PC1_1 to retrieve an email with vbs attachments to test the configuration.
Figure 13-1 Use SMTP / POP3 filter functionality to avoid some sensitive e-mail directly opened
Content Filtering – Mail Filters
This chapter introduces SMTP proxies and explains how to implement it.
77
DFL-900 User Manual
Chapter 13
Advertisement
Table of Contents
