How can you secure Azure Virtual Machines against unauthorized access?

Implementing Network Security Groups (NSGs) is an effective method to secure Azure Virtual Machines against unauthorized access. NSGs act as a virtual firewall, controlling inbound and outbound traffic to Azure resources based on rules defined by the user. By creating and configuring NSGs, you can restrict access to Virtual Machines by specifying which IP addresses or ranges are allowed or denied access, as well as the allowed ports and protocols. This level of granularity in traffic management is essential for protecting the VMs from unauthorized access attempts.

Other options, while important components of an overall security strategy, do not provide the same direct controls for managing access to Virtual Machines. Azure Load Balancers can help distribute traffic, but they do not inherently secure access. Azure Sentinel is a security information and event management (SIEM) solution that assists in monitoring and analyzing security events but does not directly control access to resources. Azure Policy helps enforce compliance and governance across Azure resources but does not focus specifically on securing network access to Virtual Machines. Thus, Network Security Groups are the most relevant choice for protecting against unauthorized access.