ZyXEL Communications 1000 ユーザーズマニュアル
ZyWALL USG 1000 User’s Guide
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H A P T E R
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Anti-Spam
38.1 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.
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.
38.1.1 What You Can Do in this Chapter
• Use the General screens (
) to turn anti-spam on or off
and manage anti-spam policies.
• Use the Black/White List screens (
) to set up a black
list to identify spam and a white list to identify legitimate e-mail.
• Use the DNSBL screens (
) to have the ZyWALL check
e-mail against DNS Black Lists.
38.1.2 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
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
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.
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.