I am in the process of setting up a virtualized OPNsense firewall on Proxmox on a Thinkcentre 720q. The proxmox host has 3 network interfaces.

  • A dual NIC gigabit card where one interface is for WAN and other for LAN, say eth1 and eth2
  • Another interface which came with the PC itself, say eth3

PS: I also have a switch for all my other devices.

After some research, I have understood that

  1. Passing (pass-through) the NIC to the OPNsense VM is better for performance
  2. Passing it through removes the interface from the host OS
  3. If passing is not done correctly, you may lose access to Proxmox.

My questions are

  1. How do I set eth2 to be the LAN port and also use it connect to proxmox?
  2. If I use point #1 (eth2 for LAN), how much will the throughput of eth2 be affected? (My ISP provides me symmetrical 320 Mbps link speed)
  3. If I use point #1, will local traffic (traffic handled by my switch) be affected?
  4. (Optional/Experimental) Since I have a spare port (eth3), can I use it for special purpose (a dedicated management port which will work even if OPNsense is down)?
  5. If I use point #4, my switch will have two ethernet connections from the proxmox host. Will this cause loops and kill my network?

You can answer this selectively by mentioning the question number.

If you have a better idea regarding how to setup OPNsense on Proxmox, please share.

  • chief@lemmy.zipEnglish
    0·
    29 days ago

    I think you have a typo here, eth1 is WAN not WLAN? you can configure eth3 to have a hardcoded ip. E.g. 192.168.1.2 - OPNsense must be aware that this ip has been assigned to a device so that the DHCP server doesn’t assign it to a different device. When the VM goes down you can still configure the network manually on your PC and access proxmox directly. Regarding routing tables, devices on the same subnet are routed directly, all other destinations usually go via the router. So 192.168.1.0/24 (Assuming /24 subnet) will work fine even if the router goes down as long as the connected device have a valid IP address in this segment. This is why the hardcoded ip will still work.

    I use this setup myself, with the complication that I am using vlans. So for this to work I need to connect to the correct physical port on my switch, but you do not have this additional complexity.

    I saw that you added the detail that you’re also running another vm - AFAIR you could route that via the management port as well with via proxmox without added complexity.