Network Configuration

Proper network configuration is crucial for Proxmox VE performance and security. This guide covers essential networking concepts and configurations.

Network Interfaces Overview

Proxmox VE uses Linux networking with additional virtualization-specific features for VM and container networking.

Interface Types

Physical Interfaces: Direct hardware network adapters
Bridges: Virtual switches for VM/CT connectivity
Bonds: Link aggregation for redundancy and performance
VLANs: Network segmentation and isolation

Bridge Configuration

Bridges are essential for VM and container networking:

Navigate to Datacenter → Node → System → Network
Click Create → Linux Bridge
Configure bridge settings:
- Name: vmbr0 (convention)
- IPv4/CIDR: Your network configuration
- Gateway: Network gateway IP
- Bridge ports: Physical interface (e.g., enp0s3)

Edit /etc/network/interfaces:

auto lo
iface lo inet loopback

iface enp0s3 inet manual

auto vmbr0
iface vmbr0 inet static
    address 192.168.1.100/24
    gateway 192.168.1.1
    bridge-ports enp0s3
    bridge-stp off
    bridge-fd 0

Apply changes:

systemctl restart networking

VLAN Configuration

VLAN configuration requires VLAN-aware switches and proper planning to avoid network isolation issues.

VLAN-Aware Bridge

auto vmbr0
iface vmbr0 inet static
    address 192.168.1.100/24
    gateway 192.168.1.1
    bridge-ports enp0s3
    bridge-stp off
    bridge-fd 0
    bridge-vlan-aware yes
    bridge-vids 2-4094

VLAN Interface

auto vmbr0.100
iface vmbr0.100 inet static
    address 192.168.100.1/24
    vlan-raw-device vmbr0

Bond Configuration

Link aggregation for redundancy and increased bandwidth:

auto bond0
iface bond0 inet manual
    bond-slaves enp0s3 enp0s8
    bond-miimon 100
    bond-mode active-backup
    bond-primary enp0s3

auto vmbr0
iface vmbr0 inet static
    address 192.168.1.100/24
    gateway 192.168.1.1
    bridge-ports bond0
    bridge-stp off
    bridge-fd 0

auto bond0
iface bond0 inet manual
    bond-slaves enp0s3 enp0s8
    bond-miimon 100
    bond-mode 802.3ad
    bond-xmit-hash-policy layer2+3
    bond-lacp-rate fast

auto vmbr0
iface vmbr0 inet static
    address 192.168.1.100/24
    gateway 192.168.1.1
    bridge-ports bond0
    bridge-stp off
    bridge-fd 0

Firewall Configuration

Enable Datacenter Firewall

Datacenter → Firewall → Options
Enable Firewall
Configure default policies:
- Input Policy: DROP or ACCEPT
- Output Policy: ACCEPT
- Forward Policy: ACCEPT

Security Groups

Create reusable rule sets:

Web Server Rules

Database Rules

Node-Level Rules

# Allow SSH from management network
IN SSH(ACCEPT) -source 192.168.1.0/24

# Allow Proxmox web interface
IN ACCEPT -p tcp -dport 8006

# Allow cluster communication
IN ACCEPT -source 192.168.1.0/24 -p tcp -dport 5404:5405
IN ACCEPT -source 192.168.1.0/24 -p udp -dport 5404:5405

Advanced Networking

Software-Defined Networking (SDN)

SDN provides advanced networking features like VXLANs, EVPN, and network controllers.

Datacenter → SDN
Create Zones, VNets, and Subnets
Apply configuration to cluster

Network Troubleshooting

Common network diagnostic commands:

# Check interface status
ip addr show

# Test connectivity
ping -c 4 gateway_ip

# Check bridge configuration
brctl show

# Monitor network traffic
tcpdump -i vmbr0

# Check firewall logs
journalctl -f | grep pve-firewall

Performance Optimization

Network Tuning

# Increase network buffer sizes
echo 'net.core.rmem_max = 134217728' >> /etc/sysctl.conf
echo 'net.core.wmem_max = 134217728' >> /etc/sysctl.conf
echo 'net.ipv4.tcp_rmem = 4096 87380 134217728' >> /etc/sysctl.conf
echo 'net.ipv4.tcp_wmem = 4096 65536 134217728' >> /etc/sysctl.conf

# Apply changes
sysctl -p

VM Network Performance

Use VirtIO network adapters for best performance
Enable Multiqueue for high-traffic VMs
Consider SR-IOV for maximum performance

Regular network monitoring helps identify bottlenecks and optimize performance for your specific workload.

Network Configuration

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