Enterprise Zero Trust Traffic Flow Architecture

This module defines the end to end traffic flow model for the Enterprise Hybrid HCI Platform. It brings together the identity, segmentation, and telemetry concepts described across earlier modules into a single, unified zero trust architecture.

The objective is to document how users, applications, services, and workloads communicate within the enterprise while continuously verifying trust at every stage.

Zero trust in this architecture is not a product. It is a security and operational model built on three core pillars:

• Identity Aware Access
• Microsegmentation
• Continuous Verification

Zero Trust Principles in the Enterprise

The traffic flow model enforces several fundamental principles:

1. No implicit trust in networks or IP ranges
   All access is defined by identity, role, device state, and policy.

2. Least privilege access
   Only the required flows are permitted. All others are denied and logged.

3. Segmentation of users, workloads, and data
   Zones, tiers, and workloads are isolated through VLANs, firewalls, routing, and identity based controls.

4. Continuous verification
   Authentication, authorization, and telemetry are evaluated throughout each session.

5. Assume breach
   Detection, containment, and rapid response guide design decisions.

Identity Aware Access Flows

Identity is the primary enforcement mechanism across the architecture. It governs both user and workload traffic.

User Flow (Internal or Remote)

Typical flow for a user accessing an internal application:

1. User authenticates with IdAM using MFA through internal or DMZ gateways.
2. Identity provider issues a token or session with claims, roles, and attributes.
3. User attempts to access a published internal application.
4. DMZ reverse proxy validates the identity token and authorizes access.
5. Traffic is forwarded to the Web Tier in the Application Hosting Block.
6. Application Tier validates user identity, roles, and entitlements.
7. Application Tier communicates with the Database Tier using service identities.
8. All events are logged to SIEM for verification and anomaly analysis.

Identity validation occurs at every tier, not just at authentication.

Administrative Access Flow

Administrative access requires additional controls:

1. Administrator authenticates using MFA.
2. Administrator enters a privileged access workflow or VDI secure jump environment.
3. Administrative role is granted only after workflows confirm approval and device posture.
4. Access to infrastructure, firewall, network, or database systems is brokered through identity aware rules.
5. All admin sessions are logged, monitored, and subject to session recording if required.

Administrators never access infrastructure directly from user networks.

Workload to Workload Flow

Service to service communication relies on identity and policy:

1. Workload authenticates to identity provider or service mesh.
2. Service receives a workload identity token or certificate.
3. Policy engine determines allowed flows.
4. Network segmentation and host based controls enforce these policies.
5. Logs are forwarded to SIEM for behavior analysis.

Examples:

• Web Tier workload calling Application Tier API
• Microservice calling another microservice in Kubernetes
• Application Tier workload accessing Database Tier

Network reachability alone never grants access.

Microsegmentation

Microsegmentation ensures each workload, tier, and zone is isolated from others. Only well defined, authorized flows are allowed.

Segmentation Layers

The architecture uses multiple segmentation layers:

Network Segmentation

• VLANs and VXLAN overlays
• VRFs or virtual routing instances
• Tier based firewall zones

Application Segmentation

• Identity based routing
• Reverse proxy filtering
• API gateway policy enforcement

Host Level Segmentation

• Host based firewalls
• Kubernetes network policies
• Service mesh sidecar enforcement

Data Segmentation

• Database schema permissions
• Row and column level access policies

Segmentation reduces the blast radius of any compromise.

Allowed Flow Patterns

Only the following directional flows are permitted:

• DMZ to Web Tier for published application entry
• Web Tier to Application Tier for business logic
• Application Tier to Database Tier for data retrieval
• Management Networks to Infrastructure Tier for administrative tasks
• Telemetry Channels from all tiers to SIEM and monitoring systems

Flows not in the allowed list are denied and logged.

End to End Zero Trust Traffic Examples

The following examples illustrate traffic sequences through the architecture.

Example 1: External User Accessing a Published Application

1. User connects to public URL.
2. Edge firewall permits traffic to DMZ WAF based on allow list.
3. WAF terminates TLS, enforces security policies, and authenticates user.
4. Authorized traffic is forwarded to internal Web Tier.
5. Web Tier validates session and calls Application Tier.
6. Application Tier uses a service identity to query Database Tier.
7. Database returns results to Application Tier.
8. Application Tier sends processed response to Web Tier.
9. Web Tier forwards response to user via DMZ intermediary.
10. SIEM correlates access logs from WAF, Web Tier, Application Tier, and Database Tier.

Example 2: Administrator Accessing Firewall Management

1. Administrator logs into VDI secure admin environment.
2. MFA and privileged access workflow validate role and device posture.
3. Admin session is restricted to Management Network segments.
4. Session connects to firewall management interface via secure protocols.
5. Changes are logged, correlated, and verified by SIEM.
6. Any abnormal behavior triggers real time alerts.

Example 3: Microservice Calling a Backend API in Kubernetes

1. Microservice authenticates to identity provider or service mesh.
2. It receives a workload identity token.
3. Kubernetes network policies allow communication only to designated services.
4. Service mesh validates identity and enforces policy.
5. Telemetry flows from sidecar proxies to monitoring and SIEM.
6. Anomalies in request volume or patterns are flagged.

Continuous Verification

Zero trust requires constant evaluation of trust signals throughout each session.

Verification sources include:

• IdAM authentication events
• MFA challenges and failures
• WAF inspection results
• Application access logs
• Database query patterns
• EDR telemetry from workloads
• Network flow analytics
• Vulnerability scan data
• Behavioral analytics from SIEM

These signals determine whether to maintain, escalate, or terminate access.

Automated Enforcement Actions

When risk signals are detected, the architecture supports:

• Session termination
• MFA challenges
• Temporary isolation of workloads
• Adaptive rate limiting
• Blocking of IPs, users, or tokens
• Notifications to administrators

Continuous verification reduces the window of opportunity for threats.

Multi Site Zero Trust Traffic Model

Traffic flows follow the same principles across all sites:

• User traffic enters through the nearest DMZ
• Application logic runs in Primary or DR depending on failover state
• Database synchronization ensures data consistency
• Identity and policy enforcement remains consistent across sites
• Telemetry is aggregated centrally for unified analysis

Out of Region DR functions as a last resort and maintains minimal but essential identity and telemetry services.

Implementation Options

The zero trust model is vendor neutral. The following categories provide examples of supporting technologies.

Identity and Policy Enforcement

• Okta, Ping Identity, Entra ID, Keycloak, Authentik

Access Proxies and WAF

• F5, NGINX, NetScaler, HAProxy

Workload Identity and Service Mesh

• Istio
• Linkerd
• Envoy based service identity frameworks

Host Level Segmentation

• Native OS firewalls
• Kubernetes network policies
• EDR agent based microsegmentation

SIEM and Analytics

• Splunk
• Elastic Stack
• Sentinel
• Behavioral analytics engines

Summary

The zero trust traffic flow model provides:

• Identity first authentication and authorization
• Strict microsegmentation at every layer
• Continuous verification through centralized telemetry

This creates a secure and resilient application environment that operates consistently across data centers and cloud environments within the Enterprise Hybrid HCI Platform.