ZyXEL Communications 200 Series 用户手册
ZyWALL USG 100/200 Series User’s Guide
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H A P T E R
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Anti-Spam
33.1 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.
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.
33.1.1 What You Can Do in the Anti-Spam Screens
• 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.
• Use the Status screen (
) to see how many mail sessions the
ZyWALL is currently checking and DNSBL statistics.
33.1.2 What You Need to Know About Anti-Spam
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
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.
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.
Black List
Configure black list entries to identify spam. The black list entries have the ZyWALL 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 checks it against the black list entries. The ZyWALL classifies an e-mail that
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 checks it against the black list entries. The ZyWALL classifies an e-mail that