  We present APHRODITE, an architecture designed to reduce false positives in
network intrusion detection systems. APHRODITE works by detecting anomalies in
the output traffic, and by correlating them with the alerts raised by the NIDS
working on the input traffic. Benchmarks show a substantial reduction of false
positives and that APHRODITE is effective also after a "quick setup", i.e. in
the realistic case in which it has not been "trained" and set up optimally
