Building upon SonicOS Standard, SonicOS Enhanced is a software upgrade that provides advanced features including WAN ISP Fail-Over, Object-Based Management and Policy-Based NAT for more complex network installations. WAN ISP Fail-Over and Load Balancing. The SonicWALL TZ 170 offers the ability to configure the Optional port as a secondary WAN port, delivering highly reliable network connectivity and robust performance. This secondary WAN port can be used in "active-active" load sharing or fail-over configuration providing a highly efficient method for maximizing total network bandwidth. Object-Based Management. The SonicWALL TZ 170 provides the ability to define an object such as a user group, network address range, service or interface. When security policies change, the administrator can modify the pre-defined object and propagate the changes instantly without redefining rules, enabling businesses to implement and manage security policies easily and consistently. Policy-Based NAT. In addition to NAT (many-to-one) functionality, the SonicWALL TZ 170 exposes control of NAT policies to administrators for one-to-one NAT, many-to-many NAT, one-to-many NAT, inbound Port Address Translation (PAT), flexible NAT (for overlapping IP addresses), as well as NAT policies on selective source/destination/source translations. The result is greater control and flexibility to support and manage various NAT requirements.