Junos OS for SRX Series Services Gateways integrates the world-class network security and routing capabilities of Juniper Networks. Junos OS includes a wide range of packet-based filtering class-of-service (CoS) classifiers and traffic-shaping features as well as a rich extensive set of flow-based security features including policies screens network address translation (NAT) and other flow-based services. Traffic that enters and exits services gateway is processed according to features you configure such as packet filters security policies and screens. For example the software can determine: • Whether the packet is allowed into the device • Which firewall screens to apply to the packet • The route the packet takes to reach its destination • Which CoS to apply to the packet if any • Whether to apply NAT to translate the packet’s IP address • Whether the packet requires an Application Layer Gateway (ALG)