ZyXEL Communications ZyWALL5UTM 4.0 User Manual

ZyWALL 5/35/70 Series User’s Guide

267 

Chapter 15 Anti-Spam

The following table describes the labels in this screen. 

Table 85   Anti-Spam: General

General Setup

Enable Anti-spam

Select this check box to enable the anti-spam feature. 

Note: The anti-spam feature checks all SMTP and POP3 e-

mail going through the ZyWALL, regardless of through 
which port the e-mail came in or to which port it is going.

Action for Spam Mails

Use this section to set how the ZyWALL is to handle spam mail.

Phishing Tag

Enter a message or label (up to 16 ASCII characters) to add to the mail 

subject of e-mails that the anti-spam external database classifies as phishing.

Note: You must register for and enable the anti-spam external 

database feature in order for the ZyWALL to use this tag 
(see Chapter 10 on page 185 for details).

Spam Tag

Enter a message or label (up to 16 ASCII characters) to add to the mail 

subject of e-mails that the ZyWALL classifies as spam.

Forward SMTP & POP3 

mail with tag in mail 

subject

Select this radio button to have the ZyWALL forward spam e-mail with the tag 

that you define.
Even if you plan to use the discard option, you may want to use this initially 

as a test to check how accurate your anti-spam settings are. Check the e-

mail the ZyWALL forwards to you to make sure that unwanted e-mail is 

marked as spam and legitimate e-mail is not marked as spam.

Discard SMTP mail. 

Forward POP3 mail with 

tag in mail subject

Select this radio button to have the ZyWALL discard spam SMTP e-mail. The 

ZyWALL will still forward spam POP3 e-mail with the tag that you define.

Action taken when mail 

sessions threshold is 

reached

The anti-spam feature limits the number of concurrent e-mail sessions. An e-

mail session is when an e-mail client and e-mail server (or two e-mail 

servers) connect through the ZyWALL. Use this section to configure what the 

ZyWALL does when the number of concurrent e-mail sessions goes over the 

threshold (see the appendix of product specifications for the threshold).
Select Forward to have the ZyWALL allow the excess e-mail sessions 

without any spam filtering.
Select Block to have the ZyWALL drop mail connections to stop the excess 

e-mail sessions. The e-mail client or server will have to attempt to send or 

receive e-mail later when the number of e-mail sessions is under the 

threshold.

Apply

Click Apply to save your changes back to the ZyWALL.

Reset

Click Reset to begin configuring this screen afresh.

Click SECURITY, ANTI-SPAM, External DB to display the Anti-Spam External DB 
screen. Use this screen to enable or disable the use of the anti-spam external database. You can 
also configure the spam threshold and what to do when no valid spam score is received. You 
must register for this service before you can use it (see 

 for details).