This document summarizes an approach for using data mining algorithms to detect network intrusions and prevent security threats. It analyzes two datasets - one containing 997 records and another containing 11,438 records - using various classification algorithms in Weka to determine the best performing ones. The algorithms examined include PART, SMO, HyperPipes, Filtered Classifier, Random Forest, Naive Bayes Updateable and KStar. Classification rate and false positive rate are used to evaluate performance. The document also discusses related work on intrusion detection using neural networks, genetic algorithms and other approaches.