Answer: Azure Firewall

The question asks for a service that filters network traffic across multiple Azure subscriptions and virtual networks. Azure Firewall is the correct answer because it is a centralized, managed firewall service designed specifically for this purpose. It provides network and application-level filtering that spans subscriptions and VNets, as confirmed by the official documentation and highly upvoted community comments (e.g., Min_Thu's comment with 56 upvotes). In contrast, Network Security Groups (NSGs) are distributed and operate within a single subscription and VNet, not across them. Application Security Groups (ASGs) are for grouping VMs within NSGs, and Azure DDoS Protection defends against volumetric attacks but does not filter traffic based on subscriptions or VNets. The community consensus strongly supports Azure Firewall, with 100% of answers and detailed reasoning highlighting its cross-subscription capabilities.

Author: LeetQuiz Editorial Team