User Guide

36 Kaspersky Anti-Spam 3.0
DNS and DNS-based checks may result in considerably slower
message processing. Disable the method if its use reduces filter
performance noticeably.
This parameter determines the use of DNS services by the filtration
server. Individual services can be enabled / disabled in the DNS & SPF
Checks section (see section 4.3.1.2 on page 36).
Please see section 4.3.3 on page 42 for details on the configuration of
DNSBL services and their use.
• SURBL Check – use of the SURBL service.
• Use of White and Black Lists – use of white and black lists containing IP
addresses and e-mail addresses of trusted and blocked sources. For
details about the use of white and black lists please refer to section 4.3.2
on page 40).
The Apply button saves the settings. Clicking it makes the application save,
compile filtration policies and restart the filtration module. Thus, the entered
changes become effective immediately.
The Reset button returns the parameters to their initial values (i.e. it cancels
unsaved changes).
The Default button returns the settings to the default values specified for the
content filtration databases. You can also use the
button opposite a section
title in the list of default filtration policy rules to restore the default values.
In order to return to the list of general default policy rules, click the Apply button
(saving the current changes) or use the Default Rules
link in the Common menu
(discarding the changes).
4.3.1.2. The DNS & SPF Checks section
The DNS & SPF Checks section (see Fig. 6) contains the settings that define
external services used for spam recognition.
Parameters of that section allow you to enable / disable the use of the following
methods:
• Use of DNSBL services – checks of the sender's IP address using a set
of DNSBL services. The list of services to use for the checks can be
customized on the Policies → Common → DNS Black Lists page.
Please see section 4.3.3 on page 42 for details.
• Check ip addresses in DNS – instruction to check the presence of
sender's IP address in DNS (reverse DNS lookup).