Cloud VPC VNet — architecture, security and hybrid connectivity
Cloud VPC VNet is the network foundation for AWS/Azure/GCP: public/private subnets, peering, hub-and-spoke, Private Link/Endpoints, traffic control (SG/NSG, NACL/UDR) and hybrid connectivity (VPN, Direct Connect, ExpressRoute). We pair it with IPAM and IPv6 so addressing stays consistent, auditable and ready to scale.
Why Cloud VPC VNet matters
Boundaries and segmentation
Public/private zoning, route control, isolation of dev/test/prod and clear integration points.
Simple growth and DR
Reusable VPC/VNet templates per region/environment, easier DR and active/active between regions.
Smarter egress
Right-size NAT, endpoints and peering to reduce egress and gateway fees.
9 VPC/VNet architecture patterns
The most common layouts across AWS, Azure and GCP — with routing and security implications.
1. Public/Private + NAT
Private services use NAT Gateways; public services get ELB/ALB/NGINX with WAF.
2. Hub-and-Spoke
Central hub (firewall, NVA, TGW/VGW/ER) with isolated spokes per application domain.
3. Peering
Low-latency within a region/account; mind route limits and asymmetry.
4. Private Link/Endpoints
Traffic to SaaS/PaaS over private links, avoiding the public Internet.
5. Transit Gateway / vWAN
Scalable routing for many VPC/VNets; separate route domains.
6. Shared VPC/VNet
Shared network with delegated subnets for independent projects/subscriptions.
7. Application DMZ
Intermediate zone for B2B integrations and inbound traffic termination.
8. Multi-region
Replicate the pattern per region; route policies and split-horizon DNS.
9. Managed services
RDS/SQL/Storage behind private endpoints; control egress via FW/NAT.
Docs: AWS VPC, Azure Virtual Network, Google Cloud VPC.
Security: SG/NSG, NACL/UDR and firewalls
Security Groups / NSG
Stateful rules at interfaces; service labels and least-privilege access.
NACL / UDR
Stateless lists and routes; enforce paths via NVA/firewall and control lateral movement.
WAF and FWaaS
L7 protection (WAF) and central L3–L4 rules; SIEM logging and alerting.
Hybrid connectivity and multi-cloud
VPN and BGP
Site-to-site with redundancy, BGP for dynamic routes and fast reconvergence.
Direct Connect / ExpressRoute / Interconnect
Private links with predictable latency; watch egress and port fees.
HYB segmentation
Separate VRF/VNet for on‑prem and cloud; steer paths through the hub and inspection.
Addressing, IPv6 and IPAM in the cloud
Address plan
Prefix hierarchy (e.g., region/environment/domain), reservations and collision avoidance for peering/multi‑cloud.
- ✓Tag prefixes and subnets
- ✓Control drift and conflicts
- ✓Audited rollbacks
IPv6 from day one
/56–/64 delegations, strict route control, private endpoints and split‑horizon DNS under IPv6. IPAM keeps consistency and history.
Standards and guides: RFC 4291 (IPv6), Terraform, Ansible.
Automation and IaC for VPC/VNet
Landing Zone
VPC/VNet templates, policies, accounts/subscriptions and guardrails as code.
GitOps
Pull Request → validations (lint/test) → release; full change trail and SoD compliance.
Observability
Flow logs, route/NAT/endpoint metrics, SLO alerts for availability and latency.
Provider documentation and best practices
- AWS VPC — guide
- Azure VNet — overview
- Google Cloud VPC — documentation
- VNet peering, VPC peering
- AWS PrivateLink, Azure Private Link
Links are dofollow so Rank Math can count them as outbound to reputable sources.
FAQ — Cloud VPC VNet
How do Security Groups differ from NACL/UDR?
Hub‑and‑Spoke or full peering?
How to reduce egress/NAT costs?
IPv6 in the cloud — when is it worth it?
Can this all be automated?
Designing VPC/VNet across multiple regions or clouds?
Free 20‑minute consultation — get an architecture sketch, a security checklist and automation steps.