  As one of the solutions to intrusion detection problems, Artificial Immune
Systems (AIS) have shown their advantages. Unlike genetic algorithms, there is
no one archetypal AIS, instead there are four major paradigms. Among them, the
Dendritic Cell Algorithm (DCA) has produced promising results in various
applications. The aim of this chapter is to demonstrate the potential for the
DCA as a suitable candidate for intrusion detection problems. We review some of
the commonly used AIS paradigms for intrusion detection problems and
demonstrate the advantages of one particular algorithm, the DCA. In order to
clearly describe the algorithm, the background to its development and a formal
definition are given. In addition, improvements to the original DCA are
presented and their implications are discussed, including previous work done on
an online analysis component with segmentation and ongoing work on automated
data preprocessing. Based on preliminary results, both improvements appear to
be promising for online anomaly-based intrusion detection.
