Network Security Groups (NSGs) and Security Lists (SLs) are two virtual firewall features that can be used for controlling traffic in an OCI Virtual Cloud Network (VCN). NSGs and SLs allow you to create stateful network filtering rules that allow or deny network traffic based on source and destination IP addresses, ports, and protocols5 NSGs are a subsequent feature designed for application components that have different security postures. NSGs are a set of security rules that you can apply to a set of VNICs in a VCN. NSGs are associated with VNICs, not subnets. You can use NSGs to implement a network security policy at the level of individual VNICs or a group of VNICs. For example, you can use NSGs to control traffic between tiers of an application deployed in a VCN5 SLs are the original virtual firewall feature from the Networking service. SLs are a set of security rules that you apply to a subnet in a VCN. SLs are associated with subnets, not VNICs. You can use SLs to implement a network security policy at the level of the subnet. For example, you can use SLs to control traffic between subnets in a VCN5