VMs not reachable in LAN and Proxmox Shell

Dec 9, 2018
we are running Proxmox VE 5.3-5 on an HP Server with two NICS:

- vmbr0,
- vmbr1,

One of the vms is a OPNSense installation with two nics:

- net0,, C6:24:9D:95:36:A2, bridge=vmbr0
- net1,, 96:6F:0D:6B:C8:4F, brdige=vmbr1 is the local network and I'm able to access the Proxmox web interface. But it is not possible to reach (via ping, ssh, http, https), neither from the lan, nor from the Proxmox shell. It is also not possible to reach any other device from the shell of the virtual machine. I have already deactivate all firewall settings, but since I'm a Proxmox newbie, I have no idea what to do next.
The vm has been accessible a couple of days, then suddenly (after installing updates?) it became inaccessible. I have already restarted the vm and the host.

Thanks for any suggestions or hints.


net1,, 96:6F:0D:6B:C8:4F, brdige=vmbr1
that should read bridge (not brdige) - but I guess that's just a typo and unrelated...

could you please post the `/etc/network/interfaces` of your PVE, and the VM-config of teh OPNSense?
auto lo
iface lo inet loopback

iface enp3s4f0 inet manual

iface enp3s4f1 inet manual

auto vmbr0
iface vmbr0 inet static
bridge-ports enp3s4f0
bridge-stp off
bridge-fd 0

auto vmbr1
iface vmbr1 inet static
bridge-ports enp3s4f1
bridge-stp off
bridge-fd 0​

bootdisk: scsi0
cores: 1
memory: 12288
name: OPNSense
net0: virtio=C6:24:9D:95:36:A2,bridge=vmbr0
net1: e1000=96:6F:0D:6B:C8:4F,bridge=vmbr1
numa: 0
onboot: 1
ostype: l26
scsi0: local-lvm:vm-100-disk-0,size=50G
scsihw: virtio-scsi-pci
smbios1: uuid=98999748-d6ac-4353-a37a-bc464f857ab8
sockets: 2
vmgenid: 2d615d96-01f8-40cd-b6a0-88c165341dc9
Thanks for your help,

The config looks ok from the proxmox side - and I see no reason, why the opnsense should not be accessible...

Sadly I don't have too much experience with OPNSense - but afaik it has FreeBSD as its base - should you have access to it's shell - the output of:
* `ifconfig -a`
* `netstat -rn`
* `arp -an`

* Else your net0 in the vm (afais the one you can't reach) is a virtio-device and net1 is a e1000 - while unlikely you could try to change the NIC-type to e1000 as well? (FreeBSD should have fitting drivers build-in for virtio-nics since 10.0-RELEASE afair).
I made some progress: is a server running on metal, while is the VM.

On the server I started tcpdump:

tcpdump -i eth3 -n -v host

And when I started to ping from within the VM, tcpdump produced the following output:

18:57:04.417203 ARP, Ethernet (len 6), IPv4 (len 4), Request who-has tell, length 46
18:57:04.417242 ARP, Ethernet (len 6), IPv4 (len 4), Reply is-at 00:24:21:54:e9:47, length 28

But the result in the VM was:

ping: sendto: Host is down

I hope someone of the network gurus may find this hint helpful.




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