The most effective and recommended method for achieving network-level isolation between environments in CloudHub is by using separate Anypoint Virtual Private Clouds (VPCs). By creating one VPC for non-production environments and another for the production environment, you establish two distinct and isolated network segments. Each VPC can then be securely connected to its corresponding customer-hosted environment (e.g., via VPN or AWS Direct Connect). This architecture ensures that applications deployed to the non-production VPC can only route traffic to the non-production backend systems, and vice-versa, thereby enforcing strict network segregation as required.

A. Modifying application properties is a configuration management practice, not a network security control. It does not prevent a misconfigured application from accessing an incorrect environment if a network path exists.

B. This approach is brittle as CloudHub workers in the shared cloud have dynamic IPs. Even with static IPs (an add-on), you cannot distinguish traffic originating from a non-production versus a production Anypoint environment if they share a VPC or reside in the shared worker cloud.

C. Business Groups provide administrative and organizational separation for users, roles, and assets within the Anypoint Platform. They do not provide any network-level isolation for deployed Mule applications.

1. MuleSoft Documentation, "Anypoint VPC Overview": "An Anypoint VPC is a logically isolated, private, and dedicated network that hosts your CloudHub workers... You can connect your Anypoint VPC to your private network using a secured VPN tunnel or AWS Direct Connect. This allows your CloudHub workers to access resources behind your corporate firewall." This establishes the VPC as the primary tool for connecting to customer-hosted environments. The best practice is to use separate VPCs to mirror the environment separation.

(Reference: MuleSoft Docs -> CloudHub -> Networking Guide -> Anypoint VPC Overview)

2. MuleSoft Documentation, "Environments": "Environments are used to logically partition your deployments... For example, you might have a development environment, a testing environment, and a production environment." This confirms that environments are a logical construct. To enforce physical network separation between these logical constructs in CloudHub, a network boundary like a VPC is required.

(Reference: MuleSoft Docs -> Anypoint Platform -> API Manager -> Environments)

3. MuleSoft Whitepaper, "Anypoint Platform Architecture: Application Network": This architectural guide emphasizes designing for security and isolation. It describes the use of Anypoint VPCs to create a secure perimeter for applications and to extend the corporate network into CloudHub. The diagrams and principles within this guide advocate for separating production and non-production network traffic, for which separate VPCs are the implementation mechanism.

(Reference: Section on "Network Architecture and Connectivity" in various MuleSoft architectural whitepapers and guides.)