Chapter 32 Anti-Spam

E-mail Header Buffer Size

The ZyWALL has a 5 K buffer for an individual e-mail header. If an e-mail’s header is longer than 5 K, the ZyWALL only checks up to the first 5 K.

DNSBL

A DNS Black List (DNSBL) is a server that hosts a list of IP addresses known or suspected of having sent or forwarded spam. A DNSBL is also known as a DNS spam blocking list. The ZyWALL can check the routing addresses of e-mail against DNSBLs and classify an e-mail as spam if it was sent or forwarded by a computer with an IP address in the DNSBL.

Finding Out More

See Section 32.7 on page 534 for more background information on anti-spam.

32.2 Before You Begin

Configure your zones before you configure anti-spam.

32.3 The Anti-Spam General Screen

Click Configuration > Anti-X > Anti-Spam to open the Anti-Spam General screen. Use this screen to turn the anti-spam feature on or off and manage anti-

 

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ZyWALL USG 20/20W User’s Guide