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.

34.1.1What 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.

34.1.2What 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

566for 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.

 

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ZyWALL USG 50 User’s Guide