1. Application Layer Packet Classifier for Linux (L7-filter). http://l7-filter.sourceforge.net/. Application Layer Packet Classifier for Linux (L7-filter). http://l7-filter.sourceforge.net/.
2. Libnids. http://libnids.sourceforge.net/. Libnids. http://libnids.sourceforge.net/.
3. Performance application programming interface. http://icl.cs.utk.edu/papi/. Performance application programming interface. http://icl.cs.utk.edu/papi/.
4. Sourcefire vulnerability research team (vrt). http://www.snort.org/vrt/. Sourcefire vulnerability research team (vrt). http://www.snort.org/vrt/.
5. Efficient string matching