In Google Cloud, firewall rules are critical components used to control network traffic to and from resources in a Virtual Private Cloud (VPC). Each firewall rule can include certain attributes like a list of source tags, which are used to associate network traffic with specific instances based on their assigned tags.
The maximum number of source tags that can be assigned to a single firewall rule is 30. This allows for flexible and organized management of traffic by enabling users to define which instances the rule will apply to based on these tags. Each tag can represent a different group of resources, making it easier to manage access controls and segmentation of network traffic.
As a result, specifying up to 30 source tags ensures that network security policies can be tailored effectively without overwhelming the rule structure. This limit balances flexibility with manageability, allowing network engineers to implement robust firewall rules while maintaining performance and clarity in their network configurations.