Intermittent Packet Loss on PPPoE (OPNsense 26.1 VM on Proxmox)

[gusto]

Preface: I am new to OPNsense and eager to learn. This is a hobby/lifestyle project for me, and I'm open to any and all feedback regarding my configuration. My goal is to understand the "why" behind the fix, not just copy-paste settings.

The Issue: I am experiencing short-term network outages. While the Gateway Monitoring shows 0% loss, the Health/Quality graphs for both WAN_IPv4 and WAN_IPv6 show significant periodic packet loss (see screenshots below).

Setup:

    Version: OPNsense 26.1.2-amd64 (Virtual Machine)

    Hypervisor: Proxmox 9.0.2 (VirtIO interfaces)

    Connectivity: Modem in Bridge/Passthrough mode using PPPoE.

Proxmox VM Config:

Code Select Expand


agent: 1
balloon: 0
cores: 12
cpu: host,flags=+aes
memory: 10240
net0: virtio=BC:24:11:DD:7B:31,bridge=vmbr0,queues=4
net1: virtio=BC:24:11:B6:05:D3,bridge=vmbr1,queues=4
net3: virtio=BC:24:11:41:FB:B5,bridge=vmbr2,queues=4
numa: 1
scsi0: local-lvm:vm-100-disk-1,discard=on,iothread=1,size=100G
scsihw: virtio-scsi-single

Findings & Steps Taken:

    Checked existing forum topics and cross-referenced with meyergru's guide.

    Gateway monitoring reports 0% loss, yet the Quality graphs show spikes (see attached).

    Hardware Check: CPU usage remains low; AES-NI is active.

Health/Quality Screenshots:


What diagnostic steps or logs should I provide next to narrow this down?

[meyergru]

Try "bridge-mcsnoop 0".

[gusto]

I already have it:

Code Select Expand

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

auto vmbr1
iface vmbr1 inet manual
        bridge-ports eth2
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094
        bridge-mcsnoop 0

auto vmbr1.20
iface vmbr1.20 inet static
        address 10.10.20.10/24
        gateway 10.10.20.1

iface vmbr1.20 inet6 static
        address fdde:5453:540e:ff13::10/64
        gateway fdde:5453:540e:ff13::1

auto vmbr2
iface vmbr2 inet manual
        bridge-ports eth1
        bridge-stp off
        bridge-fd 0
        bridge-vlan-aware yes
        bridge-vids 2-4094
        bridge-mcsnoop 0


[gusto]

usually these losses occur during high-bandwidth operations, like rdp + video call + streaming

I also configured MTU and MSS to 1492 and 1452

[meyergru]

Did you enable multiqueue on the VM's network interfaces?