Initial Installation & Configuration


Just looking on how to invoke the installer? When the live environment has been started just login with user installer and password opnsense.


The software setup and installation of OPNsense® is available for the x86-64 bit microprocessor architecture only.

Embedded vs Full

Full installs can run on SD memory cards, solid-state disks (SSD) or hard disk drives (HDD).

Since version 15.1.10 (04 May 2015) the option to install an embedded OPNsense image is also supported.

The main differences between an embedded image and a full image are:



Writes to RAM disk

Writes to local disk

No log data retention after reboot

Log data retention after reboot

Not intended for local disk writes

Suitable for disk writes.

Embedded only use, SWAP file is optional

Can enable RAM disk for embedded mode.

Embedded images (nano) store logging and cache data in memory only, while full versions will keep the data stored on the local drive. A full version can mimic the behavior of an embedded version by enabling RAM disks, this is especially useful for SD memory card installations.


See the chapter Hardware Setup for further information on hardware requirements prior to an install.

Download and verification

The OPNsense distribution can be downloaded from one of our mirrors.

The OpenSSL tool is used for file verification. 4 files are needed for verification:

  • The bzip compressed ISO file (<filename>.iso.bz2)

  • The SHA-256 checksum file (<filename>.sha256)

  • The signature file (<filename>.sig)

  • The openssl public key (<filename>.pub)

These files can be downloaded from one of the download mirrors. To download them:

  1. Go to the OPNSense download page.

  2. After selecting a mirror, right click the download button and click “open in new tab”.

  3. A popup will appear asking if you want to download the image. Say “no” for now.

  4. Remove the file name after the last slash in the URL bar, and press enter. This will take you to the directory listing for that mirror.

I.e. If you wanted to download from the US East Coast mirror:

Opening the link in a new tab would take you to this link:

You should take off the file name at the end, like this:

The OpenSSL public key is required to verify against. This file is also on the mirror directory listing page, however you should not trust the copy there. Download it, open it up, and verify that the public key matches the one from other sources. If it does not, the mirror may have been hacked, or you may be the victim of a man-in-the-middle attack. Some other sources to get the public key from include:

Note that only release announcements with images (typically all major releases) contain the public key. I.e. 22.1 would have a copy of the public key in the release announcement, but 22.1.9 would not.

Once you have downloaded all the required files and a copy of the public key, and verified that the public key matches the public key from the alternate sources listed above, you can be relatively certain that the key has not been tampered with. To verify the downloaded image, run the following commands (substituting the names in brackets for the files you downloaded):

openssl base64 -d -in <filename>.sig -out /tmp/image.sig

openssl dgst -sha256 -verify <key>.pub -signature /tmp/image.sig <image>.img.bz2

Make sure to change the “img” to “iso” in the second line if you downloaded a different installer type.

If the output of the second command is “Verified OK”, your image was verified successfully, and you can install it. If it has any other output, you may have made an error using the commands, or the image may have been compromised.

Installation Media

Depending on you hardware and use case different installation media are provided:




ISO installer image with live system capabilities running in VGA-only mode with UEFI support


USB installer image with live system capabilities running in VGA-only mode with UEFI support


USB installer image with live system capabilities running in serial console (115200) mode only with UEFI support


A preinstalled image for >=4 GB USB sticks, SD or CF cards for use with embedded devices running in serial console (115200) mode with secondary VGA support (no kernel messages though)


Flash memory cards will only tolerate a limited number of writes and re-writes. For embedded (nano) versions memory disks for /var and /tmp are applied by default to prolong CF (flash) card lifetimes.

To enable for non embedded versions: Go to System ‣ Settings ‣ Miscellaneous ‣ Disk / Memory Settings, change the setting, then reboot. Consider to enable an external syslog server as well.

Media Filename Composition


Please be aware that the latest installation media does not always correspond with the latest released version. OPNsense installation images are provided on a regular basis together with major versions in January and July. More information on our release schedule is available from our package repository, see README

OpenSSL and LibreSSL

OPNsense images are provided based upon OpenSSL. The LibreSSL flavor can be selected from within the GUI (System ‣ Firmware ‣ Settings). In order to apply your choice an update must be performed after save, which can include a reboot of the system.


Boot preparation

After preparing the installation media, we need to make sure we can access the console (either via keyboard and [virtual]monitor or serial connectivity) and know how to access the boot selection via the system bios. Often there’s a (function) key one should press during initial boot.


OPNsense devices from the OPNsense shop use <ESC> to enter the bios and boot selection options.


Serial connectivity settings for DECXXXX devices can be found here

Installation Method

Download the installation image from one of the mirrors listed on the OPNsense website.

The easiest method of installation is the USB-memstick installer. If your target platform has a serial interface choose the “serial” image. If you need to know more about using the serial interface, consult the serial access how-to.

Write the image to a USB flash drive (>=1 GB) or an IDE hard disk, either with dd under FreeBSD or under Windows with physdiskwrite

Before writing an (iso) image you need to unpack it first (use bunzip2).


dd if=OPNsense-##.#.##-[Type]-[Architecture].img of=/dev/daX bs=16k

Where X = the device number of your USB flash drive (check dmesg)


dd  if=OPNsense-##.#.##-[Type]-[Architecture].img of=/dev/sdX bs=16k

where X = the IDE device name of your USB flash drive (check with hdparm -i /dev/sdX) (ignore the warning about trailing garbage - it’s because of the digital signature)


dd if=OPNsense-##.#.##-[Type]-[Architecture].img of=/dev/rsd6c bs=16k

The device must be the ENTIRE device (in Windows/DOS language: the ‘C’ partition), and a raw I/O device (the ‘r’ in front of the device “sd6”), not a block mode device.


sudo dd  if=OPNsense-##.#.##-[Type]-[Architecture].img of=/dev/rdiskX bs=64k

where r = raw device, and where X = the disk device number of your CF card (check Disk Utility) (ignore the warning about trailing garbage - it’s because of the digital signature)


physdiskwrite -u OPNsense-##.#.##-[Type]-[Architecture].img

(use v0.3 or later!)

Install Instructions

The boot process gives you the opportunity to run several optional configuration steps. It has been designed to always boot into a live environment in order to be able to access the GUI or even SSH directly. If a timeout was missed simply restart the boot procedure.

OPNsense Importer

All images feature the new “opnsense-importer” utility, which is now invoked instead of the early installer. You can stop the automatic timeout by pressing any key. Afterwards you will have the opportunity to select a disk to import from. If the option times out or the importer is exited without a disk selection, the factory defaults will be used for the boot.

The next prompt will be for manual interface selection. This step is well-established since OPNsense 15.7 .

Live environment

The system will then continue into a live environment. If the config importer was used previously on an existing installation, the system will boot up with a fully functional setup, but will not overwrite the previous installation. Use this feature for safely previewing upgrades.

If you have used a DVD, VGA, Serial image you are by default able to log into the root shell using the user “root” with password “opnsense” to operate the live environment.

The GUI will listen on for user “root” with password “opnsense” by default unless a previous configuration was imported. Using SSH, the “root” and “installer” users are available as well on IP Note that these install medias are read-only, which means your current live configuration will be lost after reboot.

Nano image

If you have used a Nano image, your system is already up and running as it is designed as such. It is set to read-write attempting to minimise write cycles by mounting relevant partitions as memory file systems and reporting features disabled by default.

Create a bootable USB flash drive with the downloaded and unpacked image file. Configure your system to boot from USB.

Install to target system

If you have used a DVD, VGA, Serial image you are by default able to start the installer using the user “installer” with password “opnsense”. On a previously imported configuration the password will be the same as root’s password.

Should the installer user not work for any reason, log in as user “root”, select option 8 from the menu and type “opnsense-installer”. The “opnsense-importer” can be run this way as well should you require to run the import again.

The installer can always be run to clone an existing system, even for Nano images. This can be useful for creating live backups for later recovery.

The installation process involves a few simple steps.


To invoke the installer login with user installer and password opnsense


The installer can also be started from the network using ssh, default ip address is

  1. Keymap selection - The default configuration should be fine for most occasions.

  2. Install (UFS|ZFS) - Choose either a UFS or ZFS filesystem. ZFS is in most cases the best option as it is the most reliable option, but does require enough memory (a couple of gigabytes at least).

  3. Partitioning (ZFS) - Choose a device type. When using a single disk the default option (stripe) is usually fine.

  4. Continue with recommended swap (UFS) - Yes is usually fine here unless the install target is very small (< 16GB)

  5. Root Password - Choose a new root password

  6. Complete Install - Exits the installer and reboots the machine

  7. Reboot - The system is now installed and needs to be rebooted to continue with configuration.


You will lose all files on the installation disk. If another disk is to be used then choose a Custom installation instead of the Quick/Easy Install.

Initial configuration

After installation the system will prompt you for the interface assignment, if you ignore this then default settings are applied. Installation ends with the login prompt.

By default you have to log in to enter the console.

Welcome message

* * * Welcome to OPNsense [OPNsense 15.7.25 (amd64/OpenSSL) on OPNsense * * *

WAN (em1)     -> v4/DHCP4:
LAN (em0)     -> v4:

FreeBSD/10.1 (OPNsense.localdomain) (ttyv0)



A user can login to the console menu with his credentials. The default credentials after a fresh install are username “root” and password “opnsense”.

VLANs and assigning interfaces

If choose to do manual interface assignment or when no config file can be found then you are asked to assign Interfaces and VLANs. VLANs are optional. If you do not need VLANs then choose no. You can always configure VLANs at a later time.

LAN, WAN and optional interfaces

The first interface is the LAN interface. Type the appropriate interface name, for example “em0”. The second interface is the WAN interface. Type the appropriate interface name, eg. “em1” . Possible additional interfaces can be assigned as OPT interfaces. If you assigned all your interfaces you can press [ENTER] and confirm the settings. OPNsense will configure your system and present the login prompt when finished.

Minimum installation actions

In case of a minimum install setup (i.e. on CF cards), OPNsense can be run with all standard features, except for the ones that require disk writes, e.g. a caching proxy like Squid. Do not create a swap slice, but a RAM Disk instead. In the GUI enable System ‣ Settings ‣ Miscellaneous ‣ RAM Disk Settings and set the size to 100-128 MB or more, depending on your available RAM. Afterwards reboot.

Enable RAM disk manually


Then via console, check your /etc/fstab and make sure your primary partition has rw,noatime instead of just rw.


The console menu shows 13 options.

0)     Logout                              7)      Ping host
1)     Assign interfaces                   8)      Shell
2)     Set interface(s) IP address         9)      pfTop
3)     Reset the root password             10)     Filter logs
4)     Reset to factory defaults           11)     Restart web interface
5)     Reboot system                       12)     Upgrade from console
6)     Halt system                         13)     Restore a configuration

Table: The console menu


OPNsense features a command line interface (CLI) tool “opnsense-update”. Via menu option 8) Shell, the user can get to the shell and use opnsense-update.

For help, type man opnsense-update and press [Enter].

Upgrade from console

The other method to upgrade the system is via console option 12) Upgrade from console


An update can be done through the GUI via System ‣ Firmware ‣ Updates.