Virtualizing with Proxmox® VE

This following article is about building and running pfSense® software on a virtual machine under Proxmox Virtual Environment (VE). The guide also applies to any newer Proxmox VE version. Article covers Proxmox VE networking setup and firewall virtual machine setup process. The guide does not cover how to install Proxmox VE.

A basic, working, virtual machine will exist by the end of this article.


  • Proxmox VE host is up and running

  • Host has at least two network interfaces available for WAN and LAN.

  • pfSense software ISO image is present on the Proxmox VE host

Basic Proxmox VE networking

First create two Linux Bridges on Proxmox VE, which will be used for LAN and WAN on the firewall VM.

  • Select the host from the server view

  • Navigate to System > Network

This example uses enp4s0 and enp5s0 interfaces for the firewall, while enp3s0 is for Proxmox VE management. The naming of interfaces will vary depening on the hardware involved (interface type, bus location, etc.).

  • Click Create

  • Select Linux Bridge

  • Enter enp4s0 under Bridge ports


Repeat the process to add another Linux Bridge, this time add enp5s0 under Bridge ports.

  • Click Apply Configuration to configure the new interfaces in the OS

  • Click Yes to confirm the action

Proxmox VE networking should now display two Linux bridges like on the following screenshot.


If the interfaces do not show as Active, reboot the Proxmox VE host.


Creating a Virtual Machine

After creating WAN and LAN Linux bridges, now proceed to create a new virtual machine.

  • Click Create VM from the top right section to display the new virtual machine wizard

  • Navigate to the General tab

  • Enter a Name for the VM (e.g. firewall)

  • Navigate to the OS tab

  • Set the following options:

    Use CD/DVD disc image file:




    ISO image:

    Select the previously uploaded ISO image

    Guest OS Type:


  • Navigate to the System tab

  • Set the following options:

    Graphic card:



    The SPICE console uses less CPU when idle and supports more advanced console features than the default console. It is compatible with the VNC Proxmox VE console as well as the more advanced virt-viewer console application.

  • Navigate to the Hard Disk tab

  • Set the following options:


    VirtIO Block

    Disk Size:

    Enter an appropriate disk size, no less than 8 GB.

  • Navigate to the CPU tab

  • Set the following options:




    1 or more cores as needed


    Host to match the CPU on the hypervisor hardware.

    Extra CPU Flags:

    These settings adjust the CPU capabilities and behavior of the guest. If using Host for Type these can likely be left at the default.

    When setting a CPU type other than Host, consider setting the AES flag to + (On) which allows the guest to use AES-NI (Cryptographic Accelerator Support).

  • Navigate to the Memory tab

  • Set the following options:


    At least 1024 MB

  • Navigate to the Network tab

  • Set the following options:




    VirtIO (paravirtualized)

  • Navigate to the Confirm tab

  • Review the settings and make any final corrections if necessary

  • Click Finish

  • Wait for the VM creation process to finish

Now add another network adapter to the VM:

  • Expand the Server View list on the left to show the contents under Datacenter and the name of this hypervisor node (e.g. pve, proxmox, etc.)

  • Select the newly created virtual machine from list

  • Click Hardware in the right pane

  • Click Add

  • Click Network Device

  • Set the following options:




    VirtIO (paravirtualized)

  • Click Add

Review the hardware list for the VM and confirm it now contains two network interfaces.

Starting and configuring the virtual machine

After creating a new virtual machine and adding network interfaces, it is time to start the virtual machine.

  • Expand the Server View list on the left to show the contents under Datacenter and the name of this hypervisor node (e.g. pve, proxmox, etc.)

  • Select the newly created virtual machine from list

  • Click Start

  • Click Console on the left, under Summary


    The Console button at the top will launch the console in a new window, which depending on the settings may require an additional client installation such as virt-viewer.

When the VM starts it will boot into the installer automatically. From there, follow the installation steps as usual, and reboot when finished.

See also

See Installation Walkthrough for a detailed walkthrough of the installation process.

After the virtual machine reboots, the console will stop at an interfaces assignment prompt.

  • Type n and press Enter to skip VLAN configuration

  • Enter vtnet0 for WAN

  • Enter vtnet1 for LAN

  • Press Enter if prompted for additional interfaces

  • Type y and press Enter to complete the interface assignment

After interfaces have been assigned, the VM will complete the boot process.

Disable Hardware Checksums with Proxmox VE VirtIO

When using VirtIO interfaces in Proxmox VE, network interface hardware checksum offloading must be disabled. Current versions of pfSense software attempt to disable this automatically for vtnet interfaces, but the best practice is to double check the setting in case changes in Proxmox VE result in the automatic process failing.


Do not skip this step, otherwise the virtual machine will not properly pass traffic. Accessing the firewall may be sluggish at first, but changing this setting will correct that as well.

After the installation and interfaces assignment processes are complete, connect to the assigned LAN port from another computer or VM on the LAN-side bridge.

To disable hardware checksum offload:

  • Navigate to System > Advanced, Networking tab

  • Locate the Networking Interfaces section

  • Check Disable hardware checksum offload

  • Click Save

  • Reboot the firewall from Diagnostics > Reboot or the console menu


Congratulations, the virtual machine installation and configuration on Proxmox VE is now complete.

Booting UEFI

pfSense software can boot UEFI in a Proxmox VE guest but doing so requires a few extra steps.

When creating the VM:

  • Set Machine to q35

  • Set BIOS to OVMF (UEFI)

  • Add an EFI disk when prompted

  • Pick the storage for the EFI disk, other settings can remain at defaults


An existing non-UEFI VM can be reconfigured to boot UEFI with these settings on its Hardware but the process is more error prone. For example, the EFI disk is a separate manual process and not semi-automated as it is when creating a VM.

After creating the VM:

  • Edit the VM Hardware and add a serial port device


    On some versions of pfSense software the EFI boot process for a ProxMox VE VM works more reliably with a serial port present in the VM hardware, even if the OS is not actively using the port.

On the first boot, go into the boot settings and disable secure boot:

  • Hit Esc while the boot splash screen is visible

  • Select Device Manager

  • Select Secure Boot Configuration

  • Uncheck Attempt Secure Boot

  • Press F10 to save

  • Press Esc to exit

  • Reset the VM

With secure boot disabled the VM can now boot with UEFI from the ISO as well as after installation.