User guide

A D V A N C E D A P P L I C A T I O N S E T T I N G S
97
ANTI-SPAM
This section describes the functions of Kaspersky Small Office Security 2 for Personal Computer. These functions are
missing in Kaspersky Small Office Security 2 for File Server.
Kaspersky Small Office Security includes Anti-Spam, a component that allows detection of unwanted messages (spam)
and their processing in accordance with the rules in your e-mail client. It saves time while working with e-mail.
Anti-Spam is built into the following mail clients as a plug-in:
Microsoft Office Outlook (on page 111);
Microsoft Outlook Express (Windows Mail) (on page 111);
The Bat! (on page 112);
Thunderbird (on page 113).
You can use the lists of blocked and allowed senders to specify for Anti-Spam the addresses from which messages will
be recognized as useful mail or spam. You may also assign the status of spam to the messages which are not
addressed to you directly (see page 106). Furthermore, Anti-Spam can check a message for the presence of allowed
and blocked phrases and also for phrases from the list of obscene expressions.
To enable efficient recognition of spam and useful mail by Anti-Spam, the component needs training (see section
"Training Anti-Spam" on page 99).
Component operation algorithm
Anti-Spam uses a self-training algorithm that allows the component to tell spam from useful mail better with time. The
source of data for the algorithm is the contents of the message.
Anti-Spam work consists of two stages:
1. Application of strict filtering criteria to a message. These criteria allow a quick determination as to whether the
message is spam. Anti-Spam assigns to the message spam or not spam status, the scan is stopped and the
message transferred to the mail client for processing (see algorithm steps 1 to 5 below).
2. Inspection of messages, which have passed strict selection criteria during previous steps. Such messages
cannot be unambiguously considered spam. Therefore, Anti-Spam has to calculate for them the probability of
being spam.
The Anti-Spam algorithm consists of the following steps:
1. The message sender's address is checked for its presence in the lists of allowed or blocked senders.
If a sender's address is in the allowed list, the message receives the Not Spam status.
If a sender's address is in the black list, the message receives the Spam status.
2. If a message was sent using Microsoft Exchange Server and scan of such messages is disabled, the message
is considered as not spam.
3. A message analysis is performed to check if it contains strings from the list of allowed phrases. If at least one
line from this list has been found, the message will be assigned the not spam status. This step is skipped by
default.