ZyWALL USG 50 User’s Guide
565
C
HAPTER
34
Anti-Spam
34.1
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 can also check e-mail against a DNS black list
(DNSBL) of IP addresses of servers that are suspected of being used by
spammers.
34.1.1
What You Can Do in this Chapter
•
Use the
General
screens (
Section 34.3 on page 567
) to turn anti-spam on or off
and manage anti-spam policies.
•
Use the
Black/White List
screens (
Section 34.4 on page 571
) to set up a black
list to identify spam and a white list to identify legitimate e-mail.
•
Use the
DNSBL
screens (
Section 34.6 on page 576
) to have the ZyWALL check
e-mail against DNS Black Lists.
34.1.2
What You Need to Know
White list
Configure white list entries to identify legitimate e-mail. The white list entries have
the ZyWALL classify any e-mail that is from a specified sender or uses a specified
header field and header value as being legitimate (see
E-mail Headers on page
566
for more on mail headers). The anti-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 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’s anti-spam speed and
efficiency by not having the ZyWALL perform the full anti-spam checking process
on legitimate e-mail.
19216811.live