“Zero egress” is not a standardized guarantee. To check an AI vendor’s claim, first define which data, workloads, destinations, traffic directions, dependencies, and exceptions it covers. Then compare that scope with the deployed network policy and architecture, test permitted and blocked paths, and retain the relevant logs and configuration as evidence.
What does “zero egress” mean for this deployment?
The phrase is useful only when its boundary is explicit. A claim might concern model prompts, retrieved documents, or a particular data plane while leaving control-plane traffic, telemetry, support access, or connected tools outside its scope. Cloud-provider guidance describes controls for specific services and architectures; it does not define a universal meaning for an AI vendor’s claim.
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Ask the vendor and the internal service owner to put the boundary in writing. Record:
- Which workloads, model endpoints, services, and data classes are covered.
- Which traffic directions are included: inbound, outbound, and service-to-service.
- Which destinations are permitted, including storage, retrieval, tools, telemetry, support, and administrative services.
- Which control-plane and data-plane connections, subprocessors, and regions are involved.
- What exceptions apply and how they are approved or changed.
Keep the contractual definition alongside the architecture diagram. The contract and the deployed configuration answer different questions: the former states the vendor’s commitment; the latter shows how the environment is set up.
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How do I map every path that could carry data?
Trace a request from the user to the model and back, including any retrieval, storage, agent-tool, telemetry, support, and administrative connections. For every connection, identify the enforcement point—such as a firewall rule, service perimeter, private endpoint, or proxy—and the team responsible for it.
Architecture matters. Microsoft’s Baseline Microsoft Foundry Chat Reference Architecture places a data proxy on the egress path for service dependencies and most external knowledge or tool connections. Hosted-agent outbound behavior follows a separate path through its dedicated network interface, so it should be mapped independently rather than assumed to pass through the same proxy. DNS logs can help audit and troubleshoot name lookups, but they are only one view of the path.
For each path, write down its source, destination, purpose, data involved, enforcement point, and available telemetry. If a path or owner is unknown, the claim is not yet fully testable.
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Is outbound traffic blocked by default?
Inspect the effective policy, not just a design document or a list of intended rules. A concrete test is whether outbound connections are denied by default and only explicitly required destinations are allowed. Google Cloud’s multi-agent private networking guidance describes specific allow rules followed by a general deny rule. The important evidence is the policy actually applied to the workload and the outcome when traffic matches or does not match an allowed rule.
Check each exception for its destination, purpose, scope, owner, and approval. Broad rules can undermine a narrow allow-list even when the main policy appears restrictive.
For Google Cloud workloads using VPC Service Controls
Verify that the relevant resources are inside the intended service perimeter and inspect its ingress and egress rules. Also check whether restricted VIP or private-access routing is used where applicable. Google describes VPC Service Controls as a way to help prevent data copying to resources outside a perimeter, complementary to network egress controls. Its dry-run mode can surface requests before enforcement; it is useful for observing potential impact, but it is not itself an enforcement result.
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For Azure Private Link deployments
Confirm that each private endpoint maps to the intended resource instance and that its network policies and rules have the expected effect. Microsoft’s Private Link guidance recommends monitoring endpoint bytes in and out, enabling diagnostic logs for access decisions, and reviewing activity-log changes to endpoint state. A private endpoint gives a private connectivity path to a resource; it does not by itself establish that every other outbound path is blocked.
Do private endpoints and service perimeters mean data cannot leave?
No—not on their own. Private endpoints can keep a connection to a particular service on a private path. A service perimeter can restrict movement between covered resources and resources outside its boundary. Neither fact, by itself, proves that the workload has no other route to an external destination.
Check how these controls fit with the rest of the architecture: outbound firewall policy, proxies, DNS, other network interfaces, service dependencies, and explicit exceptions. Google’s guidance for Gemini Enterprise Agent Platform describes private routes and perimeter use for that platform; it should not be generalized into a guarantee about unrelated services or an entire deployment.
Which logs help verify what happened?
Use independent telemetry from the enforcement and service layers, and confirm that collection is enabled for the relevant workload and paths.
| Evidence | What it can help establish | What to verify |
|---|---|---|
| VPC Flow Logs | Observed traffic metadata that can support detection of unusual volume or unexpected destinations. | Coverage of the relevant network interfaces, retention, delivery, and alerting. AWS’s Bedrock data-perimeter guidance describes using these logs to monitor network-access patterns. |
| DNS logs | Recorded name lookups that can aid auditing and troubleshooting. | Which resolvers and workloads are covered, how long records are retained, and whether lookups can be matched to the paths under review. |
| Diagnostic or access-decision logs | Recorded service access decisions, where the service provides them. | That the relevant diagnostic categories are enabled and that the records identify the resource and decision being assessed. |
| Activity or audit logs | Recorded changes to configuration or endpoint state, and other auditable actions. | Coverage, retention, access to the records, and whether changes can be tied to an owner and time. |
Logs show what they observed within their configured coverage. A quiet log is not proof that no path exists: collection may not cover a route, interface, service, or time period. Verify the logging configuration and scope before using the records to support a conclusion.
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How can I test allowed and denied paths?
Run controlled tests in a representative non-production environment where possible. The test method should match the actual cloud service and enforcement points; there is no single universal command for every vendor and deployment.
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- Choose the cases. Select a known required destination and a destination the policy should block. Document the expected result for each.
- Observe before enforcement where available. Use a supported dry-run or observe-only mode to identify requests that may be affected before turning on a blocking policy.
- Run the requests. Record the time, workload, source, destination, and observed outcome. Do not describe a configuration review as a packet-level test unless packets were actually inspected.
- Match outcomes to evidence. Check the relevant firewall or perimeter decision and correlate it with available flow, DNS, diagnostic, or audit records.
- Repeat after enforcement. Confirm that required traffic still succeeds and the prohibited case is denied under the enforced policy. Record any exception or unexpected result.
This is a verification approach derived from the documented controls, not a vendor-specific test procedure. A result applies only to the paths, configuration, environment, and time actually tested.
What can network controls not prevent?
Network restrictions do not prevent every form of authorized misuse. A user or service identity with legitimate access may still expose or misuse data through an allowed path. Microsoft’s Azure Databricks data-exfiltration guidance emphasizes layered protection, including data governance and audit logging, alongside network controls.
Review service identities and least-privilege permissions, data access rules, and audit events. Confirm that permissions align with the intended use of the AI workload, and that access and configuration changes can be investigated.
What evidence should the review retain?
Keep a dated record for each claim and deployment, so another reviewer can see what was in scope and what the evidence actually demonstrated.
- The vendor’s written scope and applicable contractual language.
- An architecture and path diagram, including dependencies, exceptions, and enforcement points.
- Exports or records of effective egress policy, perimeter rules, private endpoint mappings, and DNS configuration.
- Log sources, coverage, retention, delivery, and alerting settings.
- Test cases, timestamps, expected and observed allow-or-deny results, and matching telemetry.
- Exceptions, control owners, region, and the configuration or service version reviewed.
Do not describe an untested configuration as a test result. Revisit the evidence when the workload, service, region, policy, or dependencies change.
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