D-Link DFL-1500 사용자 설명서

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DFL-900/1500 User Manual
 
Chapter 22 
Content Filtering – Mail Filters 
 
193 
Chapter 22 
Content Filtering – Mail Filters 
This chapter introduces SMTP proxies and explains how to implement it. 
22.1 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. 
 
22.2 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. 
 
22.3 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 22-1 Use SMTP / POP3 filter functionality to avoid some sensitive e-mail directly opened 
 
The feature of the Mail Filter can only be available while DFL-1500 connects to the Internet via Default WAN Link.