Netgear STM300 ProSecure Web and Email Threat Management Appliance Reference Manual

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Protecting Against Email Spam

The STM integrates multiple antispam technologies to provide comprehensive protection 
against unwanted email. You can enable all or a combination of these antispam technologies. 
The STM implements these spam prevention technologies in the following order:

Whitelist. Emails from the specified sources or to the specified recipients are not 
considered spam and are accepted.

Blacklist. Emails from the specified sources are considered spam and are blocked.

Real-time blacklist. Emails from known spam sources that are collected by blacklist 
providers are blocked.

Distributed spam analysis. Emails that are detected as spam by the NETGEAR Spam 
Classification Center are either tagged, blocked, or quarantined.

File Extension By default, the File Extension field lists the most common file extensions that are detected. 

You can manually add or delete extensions. Use commas to separate different extensions. 
You can enter a maximum of 40 file extensions; the maximum total length of this field, 
excluding the delimiter commas, is 160 characters.

You can also use the drop-down list to add predefined file extensions from a specific 
category to the File Extension field:

• None. No file extensions are added to the File Extension field. This is the default setting. 

•  Executables. Executable file extensions (exe, com, dll, so, lib, scr, bat, and cmd) are 

added to the File Extension field.

• Audio/Video. Audio and video file extensions (wav, mp3, avi, rm, rmvb, wma, wmv, mpg, 

mp4, and aac) are added to the File Extension field.

• Compressed Files. Compressed file extensions (zip, rar, gz, tar, and bz2) added to the 

File Extension field.

Action

SMTP

From the drop-down list, specify an action when an email attachment with a file 
extension that is defined in the File Extension field is detected. The drop-down list 
selections and defaults are the same as the ones for the 

POP3

IMAP

File Name

Enter the file names that are detected. For example, to block the Netsky worm (which 
normally arrives as netsky.exe), enter netsky.exe. You can enter a maximum of 20 file 
names. Use commas to separate multiple file names. The maximum total length of this field 
is 400 characters, excluding the delimiter commas.

Action

SMTP

From the drop-down list, specify an action when an email attachment with a name 
that is defined in the File Name field is detected. The drop-down list selections 
and defaults are the same as the ones for the 

 section earlier in this table.

POP3

IMAP