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English Forums => General Discussion => Topic started by: MaxG on October 18, 2025, 01:35:44 AM

Title: OPNsense VM on Proxmox with SDN and VLANs; I am badly stuck :(
Post by: MaxG on October 18, 2025, 01:35:44 AM
Over the course of four weeks and endless hours I have tried to get SDN VLANs going; to no avail.

Proxmox 9.09. OPNsense 25.7.5

The following current config without any VLAN-ing is working.

On Proxmox I have:
- vmbr0 = LAN (NIC) 192.168.2.0/24
- vmbr1 = WAN (USB->Ethernet) 192.168.1.118 gw 192.168.1.1 (to get Internet connectivity for updates, etc.)
- vlanzone (ZONE VLAN)
- vnetlan in vlanzone (no subnets) VID 20
- OPNsense VM with
  - virtio net0 vbmbr0
  - virtio net1 vbmbr1

On OPNsense I have:
- vlan01 for LAN (not assigned)
- LAN vtnet0 VID 20
- WAN vtnet1

Managed switch: FS.com S3700-24T4F
- port 1 default, no VLAN tag = Proxmox
- port 2 default, no VLAN tag = PC 192.168.2.100

As mentioned, the above config works.


Now, this is what I do to get VLANs configured.

Proxmox:
- change net0 from vmbr0 to vnetlan (if I do this first I loose access to Proxmox)

OPNsense:
- change vtnet0 to vlan01

Managed switch: FS.com S3700-24T4F
- ports 13-18 on VLAN 20 access
- port 23 trunk

After these changes:
- I cannot ping anything
- cannot reach any console; except direct connect to Proxmox machine

Since I can't reach OPNsense, I have to get Proxmox back to get to the OPNsense VM shell and revert the interface assignments.

I have done this now too many times to count, and can for the life of me not figure out what I am doing wrong.

I have watched endless YouTubes, but cannot find SDN Proxmox OPNsense VLAN videos; yes, some of the combinations but not all of them.

I am now at a point where I need help with this config. If there is a means to pay someone knowledgeable, I will.
Title: Re: OPNsense VM on Proxmox with SDN and VLANs; I am badly stuck :(
Post by: meyergru on October 18, 2025, 11:06:07 AM
From what I get is that your LAN NIC is attached to one of the ports 13-18 on your switch?

In that case, if you change the vtnet0 on OpnSense to VLAN 20, what you get is a VLAN 20 in a VLAN 20 (QinQ), which certainly will not work.

You should connect the LAN NIC to port 23 (trunked) when you use LAN as VLAN 20 on OpnSense.

W/r to Proxmox, you would then have to use VLAN 20 there, too. It can be done like so:



auto eth0
iface eth0 inet manual

auto vmbr0
iface vmbr0 inet static
        bridge-ports eth0
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094
        bridge-mcsnoop 0
#Network bridge

auto vmbr0.20
iface vmbr0.20 inet static
        address 192.168.2.5/24
        gateway 192.168.2.1
        dns-nameservers 192.168.2.1
#Proxmox LAN interface


Title: Re: OPNsense VM on Proxmox with SDN and VLANs; I am badly stuck :(
Post by: MaxG on October 18, 2025, 03:43:50 PM
Thank you... yes, I connected the NIC to the trunk port. (Apologies for not being specific enough).

How do people set this up without loosing connection to Proxmox and OPNsense?

I have reverted back to what I had working, though without VLANs.

I probably should have attached my switch config too... (now attached).

In any case I will try your config. I was close... :) but missed the VLAN lines.

auto vmbr0
  iface vmbr0 inet static
  bridge-ports eno1
  bridge-stp off
  bridge-fd 0
#LAN

auto vmbr0.20
iface vmbr0.20 inet static
  address 192.168.2.2/24
  netmask 255.255.255.0
  gateway 192.168.2.1
#VLAN20

Is there anything else I can post to provide more clarity.?
Title: Re: OPNsense VM on Proxmox with SDN and VLANs; I am badly stuck :(
Post by: meyergru on October 19, 2025, 01:00:15 AM
There are some things missing:

1. You do not specify VLAN awareness and which VLANs can be used, so your OpnSense cannot access VLAN 20.
2. Use a netmask or /24, not both.
3. Other things are missing, like bridge-mcsnoop, which is also in this guide: https://forum.opnsense.org/index.php?topic=44159.0

Details matter.
Title: Re: OPNsense VM on Proxmox with SDN and VLANs; I am badly stuck :(
Post by: MaxG on October 19, 2025, 02:12:48 AM
Yes to all... this is the problem when you work with newbies; so much to get wrong.

I took a step back and set-up a test environment, simplified to the bare bones.
First test and validate switch config.
1. 4 access ports, 1. Proxmox (no OPNsense), 2 clients --> all pings in any direction
2. change Proxmox port to access and added this config --> all pings in any direction
Though the config seems excessive?!

auto lo
iface lo inet loopback

auto eno1
iface eno1 inet manual

iface enx0050b61f9434 inet manual

auto vmbr0
iface vmbr0 inet static
    address 192.168.2.2/24
    gateway 192.168.2.1
    bridge-ports eno1
    bridge-stp off
    bridge-fd 0
#LAN bridge (untagged, native VLAN)

auto vmbr1
iface vmbr1 inet manual
    bridge-ports none
    bridge-stp off
    bridge-fd 0
#WAN bridge

auto vmbr10
iface vmbr10 inet manual
    bridge-ports eno1.10
    bridge-stp off
    bridge-fd 0
    bridge-vlan-aware yes
    bridge-vids 10
#LAN VLAN 10 (tagged)

auto eno1.10
iface eno1.10 inet manual
    vlan-raw-device eno1
#VLAN 10 subinterface

source /etc/network/interfaces.d/*

which evolved to:
auto lo
iface lo inet loopback

auto eno1
iface eno1 inet manual

auto enx0050b61f9434
iface enx0050b61f9434 inet manual
#WAN (no VLAN)

auto vmbr0
iface vmbr0 inet static
    address 192.168.2.2/24
    gateway 192.168.2.1
    bridge-ports eno1
    bridge-stp off
    bridge-fd 0
    bridge-vlan-aware yes
    bridge-vids 10,30,40,50
#LAN bridge (untagged + VLANs 20,30,40,50)

auto vmbr1
iface vmbr1 inet static
    address 192.168.1.2/24
    bridge-ports enx0050b61f9434
    bridge-stp off
    bridge-fd 0
#WAN bridge (no VLAN)

source /etc/network/interfaces.d/*

... after I created VNets:

cat /etc/pve/sdn/vnets.cfg
vnet: vnetlan
    zone vlanzone
    alias VNet LAN
    tag 10

vnet: vnetdmz
    zone vlanzone
    alias VNet DMZ
    tag 30

vnet: vnetiot
    zone vlanzone
    alias VNet IoT
    tag 40

vnet: vnetgst
    zone vlanzone
    alias VNet Guest
    tag 50

... with this zone:

cat /etc/pve/sdn/zones.cfg
vlan: vlanzone
    bridge vmbr0
    ipam pve

Now the questions:
1. is this configuration suitable for installing OPNsense in a VM on this Proxmox machine?
2. What I mean, other than having to configure OPNsense, there is no further config on Proxmox required?! Correct?
3. When going through the OPNsense setup in the CLI is it correct to select the VNets and not vmbrs (except for WAN) as interface for the LAN, DMZ, IOT, Guest networks?
4. Anything else I need to do to not log me out of Proxmox or OPNsense? :)
Title: Re: OPNsense VM on Proxmox with SDN and VLANs; I am badly stuck :(
Post by: meyergru on October 19, 2025, 01:47:43 PM
IDK anything about SDN in Proxmox, sorry. Never saw the need for that.

All I can tell you is that with your previous setup, where you had your LAN on VLAN 20 access ports and the Proxmox host as trunk, you can do it with the setup I posted, such that the Proxmox host IP map also to the LAN on VLAN 20.

You can then configure the vtnet0 on OpnSense to vmbr0 and set up the LAN on VLAN 20 as well to access all of that LAN and deliver DHCP and DNS services to it. vtnet1 would then be exclusively used for WAN.