What Is It?
VDC Networking provides isolated network environments within Virtual Data Centers (VDCs). Create private LANs, configure IP addresses, and manage network topology to connect resources within data centers. VDC Networking forms the foundation for building secure, segmented cloud infrastructure with control over addressing, routing, and connectivity between resources.
Quick Facts
| Aspect | Details |
|---|---|
| Type | Virtual network infrastructure within VDCs |
| Network Types | Private and Public Layer 2 LANs |
| IP Management | Manual or DHCP-based addressing |
| IPv6 Support | Up to 256 IPv6-enabled LANs per VDC |
| Segmentation | Multiple LANs per VDC for isolation |
| Management | DCD, Cloud API |
What You Can Do
Private LAN Creation
Create isolated Layer 2 networks within VDCs. Each LAN provides private connectivity between attached resources without Internet exposure.
IP Address Management
Configure IP addressing manually or use IONOS DHCP for automatic assignment. Control IPv4 and IPv6 address allocation for connected resources.
Network Segmentation
Create multiple LANs per VDC to isolate different tiers, departments, or security zones. Separate frontend, backend, and database networks logically.
IPv6 Configuration
Every VDC automatically receives a public /56 IPv6 CIDR block, enabling true dual-stack (IPv4 + IPv6) environments. Enable IPv6 on LANs to receive /64 blocks from the VDC's /56 allocation.
IPv6 Address Allocation Hierarchy:
| Resource | CIDR Block | Source |
|---|---|---|
| VDC | /56 | Automatically assigned per VDC |
| LAN | /64 | Taken from VDC's /56 block |
| NIC | /80 | Taken from LAN's /64 block |
| Individual Address | /128 | Taken from NIC's /80 block (max 50 per NIC) |
Attach NICs to IPv6-enabled LANs to receive both IPv4 and IPv6 addresses. Each NIC gets a /80 IPv6 block and an initial /128 address automatically. Assign up to 50 IPv6 addresses (/128) per NIC. IPv6 addresses are static and remain assigned after VM restarts.
IONOS provides DHCPv6 by default for automatic IPv6 configuration. You can disable DHCPv6 if running your own DHCPv6 server. Reverse DNS (PTR records) can be created for public IPv6 addresses through Cloud DNS.
IPv6 Limitations:
- IPv6 not available for Managed Application Load Balancer, Managed Network Load Balancer, Managed NAT Gateway, IP Failover, or Managed Kubernetes
- Maximum 50 IPv6 addresses per NIC
- Deleting a VDC loses the /56 block permanently (keep the VDC and delete only components if rebuilding)
- Older Debian images (10/11) may require manual DHCPv6 client execution after boot
- Cannot change a VDC's /56 block after assignment
NIC Attachment
Connect server and Cube NICs to LANs for network connectivity. Control which resources can communicate on each network segment.
DHCP Services
Use IONOS-provided DHCP for automatic IP assignment or disable DHCP to run custom DHCP servers on your infrastructure.
Best For
| Scenario | Why It Fits |
|---|---|
| Multi-tier applications | Separate LANs for web, app, and database tiers |
| Security isolation | Segment production, staging, and development environments |
| Compliance requirements | Network-level isolation for regulated workloads |
| Private communication | Resources communicate without Internet routing |
| Large deployments | Multiple LANs organize complex infrastructures |
| IPv6 adoption | Dual-stack support for modern addressing |
Key Considerations
Billing & Costs
- Main billing: Included with VDC (no separate networking charge)
- Additional costs: None for basic LAN functionality
Limitations
- LANs are VDC-scoped
- Connectivity between VDCs requires additional services such as Cross Connect.
- Maximum 256 IPv6-enabled LANs per VDC
- Private and public LANs are both supported: private LANs isolate traffic internally, while public LANs (attached via an Internet Access element) give resources direct, routable internet access without requiring a NAT Gateway.
- Cross-region connectivity requires additional solutions
Management Options
- Data Center Designer (DCD)
- Cloud API
- LAN creation, configuration, and deletion
- IP address range management
- IPv6 enable/disable per LAN