User Guide

Using the application 47
You are also advised to enable restrictions for SMTP connections (see section
5.3 on p. 53).
Furthermore, application version 5.5 supports the technology of DNS black lists
(RBL). That technology allows blocking of mail receipt from unsafe servers
registered in the RBL database as servers sending spam. The list of DNS Black
List services is specified in the DNSBlackList parameter, [smtpgw.access]
section of the application configuration file.
4.4. Managing license keys
The right to use Kaspersky SMTP-Gateway is determined by the license key.
The key is included in the product’s distribution kit and entitles you to use the
application from the day you have purchased it and installed the key.
Kaspersky SMTP-Gateway WILL NOT work without a license key!
After the license expires, the functionality of the application will still be preserved
except for the possibility to update the anti-virus databases. You will still be able
to scan email messages for viruses and disinfect infected objects, but you will be
unable to use the databases issued after your license expiration date. Therefore,
you may not be protected against new viruses that have appeared after your
license expired.
In order to protect your computer against new viruses, we recommend that you
renew the license to use Kaspersky SMTP-Gateway.
The license key gives you the right to use the application. It contains all
information related to the license you have purchased, including the type of
license, license expiry date, information about dealers, etc.
In addition to the right to use the application during the license period, you will
have the following benefits:
• twenty-four-hour technical support
• hourly updates of the anti-virus databases
• timely notifications about new virus threats.
DNS black list service (RBL, real time black hole list) is a database
of IP addresses of mail servers performing unchecked mail delivery. If a
certain address is constantly being used for sending spam and
administration of the server used for spam distribution takes no steps to
prevent that, you can inform RBL about the spammer. The latter will be
added to the database and the record will allow automatic blocking of
mail receipt from that mail server. Various RBL services use different
policies for generation of such lists. Please examine carefully the policy
of each service before you start using it for mail filtration.