ZyXEL Communications 1000 User Manual
Chapter 38 Anti-Spam
ZyWALL USG 1000 User’s Guide
651
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.
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.
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
for more background information on anti-spam.
38.2 Before You Begin
Configure your zones before you configure anti-spam.
38.3 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-
screen. Use this screen to turn the anti-spam feature on or off and manage anti-