Setting up OPNsense not on the default IP address, with no DHCP server

[patrick3000]

Forgive me if this is the wrong forum topic. I'm brand new to OPNsense and didn't see a newbie section.

I've used PFSsense for almost ten years, but I am going to switch to OPNsense because PfSense common edition appears to be partially abandoned by its developer (at least that what it seems to me).

I have a rather complex setup, however, with multiple WANS and load balancing, VLANs, a number of firewall rules and aliases, and a VPN server. Therefore, the migration to OPNsense is going to take some work, and I'd like to leave the physical hardware running PfSense up and running for a few weeks while I configure OPNsense in a Virtualbox VM. Once I have OPNsense configured in the VM, I'm going to save the config, install OPNsense on the physical hardware, and import the config.

My problem is that I started the process today, and OPNsense out of the box installed in the VM on IP address 192.168.1.1, which is the same IP address that my PfSense firewall is installed on. So, I had to quickly shut down the OPNsense VM so as not to cause problems on my network.

Does anyone know how to install OPNsense on an IP address other than 192.168.1.1, so that I can install it in the VM without interfering with my existing PfSense firewall?

Also, I'm afraid that OPNsense will immediately start running a DHCP server, which I don't want because that would interfere with my existing DHCP server. If anyone knows a way to stop that from happening, I'd appreciate your thoughts.

[patrick3000]

I figured it out. Here is the solution, in case anyone else is in this situation. First, when you first boot the VM from the OPNsense installation iso file, it will give you a warning that 192.168.1.1 is in use (because as noted, I currently am running physical hardware with PFSense installed at that address). I ignored the warning temporarily, even though I suppose there is a risk that having two devices at the same address could cause network instability. In any event, I ignored it, and then I logged in as "installer" (not root, which is important). After that, I installed to the virtual disk and rebooted the VM. I then chose option "2" from the console, "Set Interface IP Address," and I set it to an address other than 192.168.1.1. It also asked whether I wanted to run a DHCP server, and I chose "No."

After that, I was able to log into the OPNsense web interface at the IP address I chose, and I'm begin the configuration process.

[patrick3000]

As a follow-up, I have figured out a far better way to do this. In Virtualbox, give the OPNsense VM a host only adapter, and create a client VM with an OS of your choice (I chose Linux Mint) also with a host only adapter. You will then have a private network with two virtual machines, unconnected to your real network or to the Internet. You can give the OPNsense VM whatever IP address you want on the private, host-only network. I chose the default: 192.168.1.1. It won't interfere with anything on your real network because the network is totally isolated.

Then, you can access OPNsense from the client VM and, at your leisure, configure it. Once it's configured, you'll need to save the config file (to do so, you can temporarily put the client VM on your real network, or else share the file with the host). Then, install OPNsense on the physical firewall on your network and import the config file.

Although I have not yet completed this entire process, it appears to be a good solution for anyone migrating a complex PFSense (or other router) setup to OPNsense.

[Patrick M. Hausen]

You might just as well use my Vagrant project to create the OPNsense VM exactly like you found out:
https://github.com/punktDe/vagrant-opnsense

I missed your initial post because you did not mention VirtualBox in the subject line.

[patrick3000]

I'm glad you created something to do this out of the box. I'm pretty far down this path, so I'm going to continue with my home-grown approach in Virtualbox, but I'm sure that others who are migrating to OPNsense will find your appliance useful.