Chapter 32 Anti-Spam; Overview; What You Can Do In This Chapter; What You Need To Know - ZyXEL Communications ZyWALL 110 User Manual

32.1 Overview

The anti-spam feature can mark or discard spam (unsolicited commercial or junk e-mail). Use the
white list to identify legitimate e-mail. Use the black list to identify spam e-mail. The ZyWALL/USG
can also check e-mail against a DNS black list (DNSBL) of IP addresses of servers that are
suspected of being used by spammers.

32.1.1 What You Can Do in this Chapter

• Use the GeneralProfile screens
manage anti-spam policies.
• Use the Mail Scan screen
functions.
• Use the Black/White List screens
spam and a white list to identify legitimate e-mail.
• Use the DNSBL screens
against DNS Black Lists.

32.1.2 What You Need to Know

White List
Configure white list entries to identify legitimate e-mail. The white list entries have the ZyWALL/
USG classify any e-mail that is from a specified sender or uses a specified header field and header
value as being legitimate (see
spam feature checks an e-mail against the white list entries before doing any other anti-spam
checking. If the e-mail matches a white list entry, the ZyWALL/USG classifies the e-mail as
legitimate and does not perform any more anti-spam checking on that individual e-mail. A properly
configured white list helps keep important e-mail from being incorrectly classified as spam. The
white list can also increases the ZyWALL/USG's anti-spam speed and efficiency by not having the
ZyWALL/USG perform the full anti-spam checking process on legitimate e-mail.
Black List
Configure black list entries to identify spam. The black list entries have the ZyWALL/USG classify
any e-mail that is from or forwarded by a specified IP address or uses a specified header field and
header value as being spam. If an e-mail does not match any of the white list entries, the ZyWALL/
USG checks it against the black list entries. The ZyWALL/USG classifies an e-mail that matches a
black list entry as spam and immediately takes the configured action for dealing with spam. If an e-
mail matches a blacklist entry, the ZyWALL/USG does not perform any more anti-spam checking on
C
HAPTER
(Section 32.3 on page
(Section 32.4 on page 535) to enable and configure the mail scan
(Section 32.5 on page
(Section 32.7 on page 542) to have the ZyWALL/USG check e-mail
E-mail Headers on page 531
ZyWALL/USG Series User's Guide
530
Anti-Spam
532) to turn anti-spam on or off and
537) to set up a black list to identify
for more on mail headers). The anti-
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