As security becomes more than just firewalls and antivirus software, network managers need to look beyond the usual list of security providers. Answers to security problems increasingly can be found in savvy start-ups that are leveraging their security expertise in today's insecure world.As\u00a0security\u00a0becomes more than just firewalls and antivirus software, network managers need to look beyond the usual list of security providers. Answers to security problems increasingly can be found in savvy start-ups that are leveraging their security expertise in today's insecure world.Security has a much broader meaning today than it did just a few years ago. In the area of IT security, government mandates about the levels of security in a number of areas have grown significantly.The Patriot and Homeland Security Acts and other antiterrorism legislation have placed numerous requirements on service providers to support law enforcement. Such IP surveillance and intelligence gathering is a challenging problem that companies are just beginning to address.Companies also are faced with privacy and confidentiality issues regarding personal data. Healthcare providers must comply with the recent Health Insurance Portability and Accountability Act, which requires that all individually identifiable healthcare information be protected to ensure privacy and confidentiality when it is electronically stored, maintained and transmitted. The rising demand for sophisticated high-technology surveillance systems is affecting physical security.In the venture business, we see smart start-ups redrawing their business models, leveraging their security components to take advantage of current trends. This certainly is true of several companies in which Mayfield has invested - Narus, Pixim and PostX.Narus' interactive mediation products help telecom carriers collect and analyze detailed information about their customers' service usage. Government agencies also can use the technology for lawfully authorized Internet surveillance.Pixim's silicon and software technology, known as the Digital Pixel System (DPS), vastly improves the way digital cameras capture and process images, making it possible to produce superior pictures under a variety of lighting conditions. DPS is ideal for security cameras, where picture quality is critical but lighting is problematic.PostX started out developing a secure way for consumers to receive bills and statements online. However, the company soon realized its technology also could be used for securing the delivery of network communications among a company's customers, partners and employees. PostX has found a market for its platform, PostX Enterprise, among financial service companies and healthcare providers, which are under pressure to secure communications that contain their customers' personal information.In the near future, as security cameras begin delivering digital rather than analog video, the distinction between IT security and physical security will begin to blur. Longer term, robust IT products will have to be applied to securing streaming video as it flows over networks.Security is clearly a growth market. As a result, in the upcoming months expect to see even more start-ups beginning to showcase their unique security products and leveraging their security expertise.Vasan is a general partner with Mayfield, a venture capital firm in Menlo Park, Calif. He can be reached at firstname.lastname@example.org.