Description

To prevent use of legacy networks, a project should not have a legacy network configured. Legacy networks can no longer be created, and their use is not recommended. This recommendation is to check old projects to ensure that they are not using Legacy Networks.

Rationale

Each legacy network has a single network IPv4 prefix range, and a single gateway IP address. The network is global in scope and spans all cloud regions. Subnetworks cannot be created in a legacy network, and are unable to switch from legacy to auto or custom subnet networks. Legacy networks can have an impact on high network traffic projects, and are subject to a single point of contention or failure.

Default value

By default, networks are not created in the legacy mode.

Remediation

For each Google Cloud Platform project:

1. Read Create and modify Virtual Private Cloud (VPC) networks to create a non-legacy network suitable for the organization’s requirements.
2. Read Deleting a legacy network to delete the networks in the legacy mode.

References

1. https://cloud.google.com/vpc/docs/using-legacy#creating_a_legacy_network
2. https://cloud.google.com/vpc/docs/using-legacy#deleting_a_legacy_network