Maybe this is a problem of language. Here's what you say the rule should do: 'After receiving a fact "MyModel" wich name != "aaa", if arrives another with same ip and different id after a period between 0 and 5 minutes the rule have to retract the last one and keep the first fact (the older one)' Which I would interpret as "Event 1 comes in, then event 2 comes in between 0 and 5 minutes later." Does that sound right? And here's the rule that you think fits the requirements: rule "SnortRule" salience 2 dialect "mvel" when $s1 : Snort( sig_name != "(portscan) Open Port") from entry-point "Correlator" $s2 : Snort( sig_name != "(portscan) Open Port" , id != $s1.id, ip_dst == $s1.ip_dst, this after [5m] $s1) from entry-point "Correlator" then System.out.println("****************** Snort Alert!!!!" + $s1.getData()); retract($s1); end Check out the docs, though: https://hudson.jboss.org/hudson/job/drools/lastSuccessfulBuild/artifact/t... The after operator in this case would check that (5m <= $s2.startTimestamp - $s1.endTimeStamp <= +infinity). So the rule actually implements "Event 1 comes in, then event 2 happens at leat 5 minutes later." If you use the second argument of after I think it would work: $s2 : Snort( sig_name != "(portscan) Open Port" , id != $s1.id, ip_dst == $s1.ip_dst, this after [0m,5m] $s1) from entry-point "Correlator" According to the docs this should check that (0m <= $s2.startTimestamp - $s1.endTimeStamp <= 5m). You could alternately use "overlaps". Place an @duration(5m) annotation on the Snort declaration and try this condition: $s2 : Snort( sig_name != "(portscan) Open Port" , id != $s1.id, ip_dst == $s1.ip_dst, this overlaps $s1) from entry-point "Correlator" _______________________________________________ rules-users mailing list rules-users(a)lists.jboss.org https://lists.jboss.org/mailman/listinfo/rules-users