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Proxmox — Software-Defined Networking

Advanced networking configuration using software-defined networking in Proxmox VE.

Overview

Proxmox SDN allows you to implement virtual networks using VXLAN and EVPN for multi-tenant segmentation, isolation, and dynamic network management.

Key Benefits: - Multi-tenant network isolation - Dynamic network provisioning - Overlay networks independent of physical topology - Native Kubernetes network integration

Prerequisites

  • Proxmox VE 8.1 or higher
  • Package libpve-network-perl installed
  • Jumbo frames (MTU 9000) support on physical switch (recommended)
  • All cluster nodes must be interconnected with sufficient bandwidth

Architecture

┌─────────────────────────────────┐
│   Virtual Networks (SDN)        │
│  ┌──────────────────────────┐   │
│  │ VXLAN Zone (vnnet0)      │   │
│  │ - VMs on different nodes │   │
│  │ - Encapsulated traffic   │   │
│  └──────────────────────────┘   │
└─────────────────────────────────┘
           │
    ┌──────┴──────┐
    │  EVPN       │  (Optional: Advanced routing)
    │  Routing    │
    └─────────────┘

Configuration Steps

1. Create VXLAN Zone

Navigate to: Node → SDN → Zones → Add → VXLAN

Settings: - Zone ID: vnnet0 (identifier) - VNI: Start ID for VXLAN networks (e.g., 1000) - Peers: IP addresses of other Proxmox nodes - MTU: 9000 (if jumbo frames supported)

Example configuration: 

Zone ID: vnnet0
VNI: 1000
Peers: 10.1.1.1, 10.1.1.2, 10.1.1.3
Mtu: 9000

2. Create Virtual Network

Navigate to: SDN → Vnets → Add

Settings: - VNet ID: net0 - Zone: vnnet0 - VLANs: Leave empty (handled by zone) - Subnets: Define IP ranges (e.g., 10.100.0.0/24)

3. Create Subnet (Optional)

Navigate to: SDN → Subnets → Add

Settings: - Subnet: 10.100.0.0/24 - Gateway: 10.100.0.1 (optional) - SNAT: Enable for external routing

4. Apply Configuration

Click: Apply to activate SDN configuration

Proxmox will: - Configure VXLAN encapsulation - Distribute configuration to cluster nodes - Create required network interfaces

Using SDN Networks

Create VM with SDN Network

  1. New VM → Hardware → Network Device
  2. Select: Bridge vnet0 (your SDN virtual network)
  3. Use VLAN tag (optional): Leave blank for SDN handling

Example: Assigning IP to VM

Inside VM (assuming Linux): 

# DHCP (if subnet has DHCP enabled)
dhclient eth0

# Static IP
ip addr add 10.100.0.50/24 dev eth0
ip route add default via 10.100.0.1

Monitoring

Check VXLAN Status

# On Proxmox node
ip link show

# Check active VXLAN interfaces
ip link show type vxlan

# View VXLAN forwarding database
bridge fdb show dev vxlan100

# Monitor traffic
tcpdump -i vxlan100 -n

Verify Connectivity

From VM to another VM on different node: 

ping 10.100.0.51  # Another VM on SDN network

Troubleshooting

Issue Cause Solution
VXLAN interfaces down MTU mismatch Set MTU 9000 on physical interfaces and SDN
VMs can't ping each other Zone not applied Click "Apply" in SDN interface
High latency VXLAN overhead Use dedicated network for VXLAN traffic
Traffic not encapsulated Peers not reachable Verify IP connectivity between nodes

Performance Tips

  1. Use dedicated network interface for VXLAN traffic (separate from management)
  2. Enable jumbo frames (MTU 9000) for better throughput
  3. Monitor encapsulation overhead: VXLAN adds ~50 bytes per packet
  4. Use EVPN for advanced routing in large deployments

Advanced: EVPN Routing

For dynamic route distribution between zones (requires additional configuration):

Zone: vnnet0 (VXLAN)
+ EVPN Routing
= Automatic MAC/ARP learning

Not covered in this guide; see official Proxmox documentation.

See Also