Skip to main content

Networking

This article covers how to create additional network bridges and set up an isolated network for your virtual machines — separating VM traffic from the Proxmox management interface.

After installation, Proxmox creates one Linux bridge:

  • vmbr0 — connected to your physical NIC (eth0/enp3s0), carries management and VM traffic

 

Creating a New Bridge for VM Traffic

 

  1. In the web console, go to your Node > Network
  2. Click Create > Linux Bridge
  3. Configure:
        • Name: vmbr1 (or any available name)
        • IP Address / CIDR: leave blank for a pure internal bridge (no host routing), OR assign an IP if you want the host to route between networks
        • Bridge ports: leave blank for internal-only, or enter a NIC name to connect to physical network
  4. Click Create, then click Apply Configuration
  5. Reboot may be needed for changes to take full effect

 

Assigning a VM to a New Bridge

 

  1. Select the VM > Hardware > Select the network device
  2. Click Edit, change the Bridge to vmbr1
  3. Click OK
  4. Reboot the VM

 

NAT and Routing

This step is Optional. To allow VMs on an internal bridge (vmbr1) to reach the internet through the Proxmox host, enable IP forwarding and NAT:

  1. Enable IP forwarding:
echo 'net.ipv4.ip_forward=1' >> /etc/sysctl.conf
sysctl -p
  1. Add NAT rule (replace 192.168.100.0/24 with your VM subnet):
iptables -t nat -A POSTROUTING -s 192.168.100.0/24 -o vmbr0 -j MASQUERADE
  1. Make the rule persistent (install iptables-persistent):
apt install -y iptables-persistent
Back to top