| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an electronic mail transmission host classification technology for statistically classifying the classes of a mail transmission host based on the features of an observed mail transmission host. Ž<P>SOLUTION: A mail reception server includes a mail transmission host classification part 12 for learning a plurality of features for various classes of mail transmission hosts 20, and statistically estimating and classifying the observed electronic mail transmission hosts into any of a plurality of classes based on the features. As the features of the host, features related with the IP address are defined as features A, and information written in the IP header or TCP(Transmission Control Protocol) header of an IP packet for SMTP(Simple Mail Transfer Protocol) communication tried to the mail reception server by the host 20 is defined as features B. Probability (likelihood) that the features A and B are turned to be certain achievable values when the host 20 is belonging to a predetermined class C<SB>i</SB>and preliminary probability that a certain host is belonging to the class C<SB>i</SB>is calculated, and scores are calculated for each class based on the features A and B obtained from the observed host, and the class with the highest score value is estimated as the class of an observation host. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
|
