Chapter 15 Unified Threat Management for FortiOS 5.0 : AntiVirus : Antivirus concepts : Antivirus techniques
  
Antivirus techniques
The antivirus features work in sequence to efficiently scan incoming files and offer your network optimum antivirus protection. The first four features have specific functions, the fifth, heuristics, protects against new, or previously unknown virus threats. To ensure that your system is providing the most protection available, all virus definitions and signatures are updated regularly through the FortiGuard antivirus services. The features are discussed in the order that they are applied, followed by FortiGuard antivirus.