Sourcefire received about $7.65 million in funding in Feb 02, and another $11 million in Feb 03. Sourcefire could be the #3 IDS vendor in terms of shipped units by year’s end. IDS monitors traffic on a network and based on defined rules/policies alerts administrators to possible intrusions, misuses, or defined malicious behavior. The “fundamentall mission” of IDS is data reduction, which is accomplished via stateful packet inspection and protocol anomaly detection.”]
Source: https://taosecurity.blogspot.com/2003/10/sourcefire-redefines-intrusion.html