Before You Begin; The Anti-Spam General Screen - ZyXEL Communications ZYWALL USG 20 Manual

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

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-
ZyWALL USG 20/20W User's Guide
for more background information on anti-spam.
Chapter 32 Anti-Spam
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