{"id":615,"date":"2026-01-17T11:04:32","date_gmt":"2026-01-17T10:04:32","guid":{"rendered":"https:\/\/disorder.dk\/wonderware\/?p=615"},"modified":"2026-01-17T11:04:32","modified_gmt":"2026-01-17T10:04:32","slug":"installing-virtualized-opnsense-as-vm-in-proxmox","status":"publish","type":"post","link":"https:\/\/disorder.dk\/wonderware\/2026\/01\/17\/installing-virtualized-opnsense-as-vm-in-proxmox\/","title":{"rendered":"Installing Virtualized OPNsense as VM in Proxmox"},"content":{"rendered":"\n

In this article \/ guide, I explore installing OPNsense 25.7.11 as a virtual machine in Proxmox 9.1.4. This is ultimately to try and fix slow speed issues when running it bare metal on my Minisforum TH50 mini PC with old Intel i225 NIC<\/a>.<\/p>\n\n\n\n

Other good guides, from various older versions of Proxmox \/ OPNsense: https:\/\/www.zenarmor.com\/docs\/network-security-tutorials\/opnsense-installation<\/a> and https:\/\/homenetworkguy.com\/how-to\/virtualize-opnsense-on-proxmox-as-your-primary-router\/<\/a><\/p>\n\n\n\n

We start out by having our hardware connected to a switch with\/or the main ISP router that currently has a DHCP (192.168.8.1) server running on your network. We connect the LAN interface to the switch, with a static IP in the same range as the ISP router DHCP server. We will later set the correct IP addresses and change cables around.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Installing Proxmox is a topic that I have covered earlier in a article about setting up Home Assistant as a virtual machine<\/a>. Please read this article for specifics on installing Proxmox and setting up the basics.<\/p>\n\n\n\n

A few things are however different. For a firewall we have two or more ethernet interfaces and we want them set up named to reflect their purposes. The physical network devices are named LAN and WAN. Two bridges are set up, vmbr0 for LAN and vmbr1 for WAN, we need these virtual network interfaces for the virtual machines. <\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Download OPNsense DVD, to get a bootable .iso file.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Use 7zip to extract the .iso file correctly. Windows will just open the .bz2 compressed folder and additinally show the .iso content as a folder. Unpacking the .bz2 archive with Windows results in a folder that cannot even be burned with something like ImgBurn<\/a>.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Upload the .iso file to Proxmox, to have it ready to mount as a bootable DVD. Go to local <\/strong>storage on your Proxmox node, select ISO Images<\/strong> and Upload<\/strong>.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Create VM for OPNsense<\/h3>\n\n\n\n

Create a new VM, by using the blue button “Create VM<\/strong>” in the upper right corner. Give the new VM a suitable name.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Select your uploaded .iso file and for the Guest OS you can leave this at default.<\/p>\n\n\n\n

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Create VM Select machine. q35 is the latest technology, from 2007, with PCIe support. i440fx is as old as 1996 and should only be used for older OS virtualization. I first tried default SeaBIOS, but OPNsense would not boot the installation. I went back and chose UEFI, and I disable Pre-Enroll keys, as OPNsense does not support secure boot.<\/p>\n\n\n\n

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For the disk I chose to use 128 GB of space, from a total of 374 GB free. I do not plan to run anything else on this proxmox, as I have another proxmox running Home Assistant. I will keep the main firewall computer as simple as possible. I enabled SSD simulation for better performance, this is found under Advanced options.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

The Minisforum TH50 has a Intel\u00ae Core\u2122 i5-11320H processor with 4 cores\/8 threads. I chose to use 2 cores and with the default suggested virtual CPU. I can always increase this to 4 cores or more, if needed. Proxmox itself also need some cores to run on.<\/p>\n\n\n\n

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I chose to use 12 GB of RAM, from my total of 16 GB.<\/p>\n\n\n\n

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Network only allows you to chose one interface in the initial VM creation. Additional network interfaces can be added later. Add the WAN bridge interface, that we created in the Proxmox installation. Disable firewall, as that makes no sense to use both Proxmox firewall and OPNsense firewall. It might just give you headaches from not knowing where deny rules are located. Use VirtIO and multiqueue set to same number as your selected amount of CPU cores.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Confirm the resum\u00e9 of choices made, but do not start the VM yet! We still need to add our additional network interfaces.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Select the new VM, go to hardware and add a new network interface. Add the LAN interface bridge.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

When trying to start the VM, I got an error message with “Error: bridge ‘vmbr1’ does not exist”. This was caused by the vmbr1 not being active, as it had pending changes not applied yet. Go to Proxmox network to check if its active and possibly fix it by applying configuration.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Start the 100 VM and go to the Shell tab.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Installing OPNsense<\/h3>\n\n\n\n

Once OPNsense is booted up, you can verify that the network interfaces are named correctly and get IP addresses from where you want. It is now time to start the installation, which can done by following this guide: Home Network Security \u2013 Installing OPNsense<\/a><\/p>\n\n\n\n

Once OPNsense is installed, it is time to switch around the network cables, so the new OPNsense firewall gets in between your ISP router and switch. Be sure to change any static IP addresses set in Proxmox as first thing!<\/mark><\/strong> Do not press Apply configuration before you have both interface settings changed and double checked it is correct IP ranges. You risk locking yourself out, when only operating with 2 interfaces.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

All your devices will now have to negotiate a new DHCP lease from the OPNsense DHCP server, instead of the ISP router. Cabling and DHCP servers should now be as follows, you might have used other IP address ranges.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Being able to log into the OPNsense management interface on 192.168.1.1 shows its a success! Be sure to also check 192.168.1.1:8006, if you can still access the Proxmox management interface as well.<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

Speed test now finally shows full speed from ISP router through OPNsense firewall and to my main PC.<\/p>\n\n\n\n

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OPNsense and Proxmox conclusion<\/h3>\n\n\n\n

The conclusion is that OPNsense is based on FreeBSD, which has worse driver support for older network cards, than Linux based Proxmox has. So by virtualizing OPNsense, and using virtual network bridges, OPNsense no longer have to deal with the hardware itself.<\/p>\n\n\n\n

The issue with getting Minisforum TH50 Intel i225v1 network cards to work, was a problem with OPNsense. Not switches, not cabling, not hardware acceleration, not half dead interfaces. It was OPNsense FreeBSD drivers and old Intel hardware not playing along nicely.<\/p>\n","protected":false},"excerpt":{"rendered":"

In this article \/ guide, I explore installing OPNsense 25.7.11 as a virtual machine in Proxmox 9.1.4. This is ultimately to try and fix slow speed issues when running it bare metal on my Minisforum TH50 mini PC with old Intel i225 NIC. Other good guides, from various older versions of Proxmox \/ OPNsense: https:\/\/www.zenarmor.com\/docs\/network-security-tutorials\/opnsense-installation<\/p>\n

Continue Reading “Installing Virtualized OPNsense as VM in Proxmox”<\/span> →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":638,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[76,62,77],"tags":[43,81,64,65],"class_list":["post-615","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-network","category-proxmox","category-security","tag-network","tag-opnsense","tag-proxmox","tag-virtulization"],"jetpack_featured_media_url":"https:\/\/disorder.dk\/wonderware\/wp-content\/uploads\/2026\/01\/15-start-VM_MADS-PC_jan-16-174507-2026_CaseConflict-scaled.png","jetpack_sharing_enabled":true,"jetpack_likes_enabled":true,"_links":{"self":[{"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/posts\/615","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/comments?post=615"}],"version-history":[{"count":8,"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/posts\/615\/revisions"}],"predecessor-version":[{"id":646,"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/posts\/615\/revisions\/646"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/media\/638"}],"wp:attachment":[{"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/media?parent=615"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/categories?post=615"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/disorder.dk\/wonderware\/wp-json\/wp\/v2\/tags?post=615"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}