Migrating VM can't ping between VM and OPNSense

[weidah]

Hi!

I've got a Proxmox cluster with some VMs.

So for whatever reason, after I do a live migration of a VM to a backup server the VM has no internet. OPNSense can't ping the VM and the VM can't ping OPNSense. But I can ping both from my PC and they can both ping me, we're all on the same network.
I thought it might be ARP table issue, but the MAC and IP are the same and I wouldn't be able to ping them if that were the issue. Also it's showing up correctly in the ARP table inside OPNSense

The interesting thing is though, that if I move it back it will work again. Also I saw it do an ARP broadcast in Wireshark after migrating.

I'm really confused and have no idea where to start looking.


EDIT:

It even got an IP from the DHCP server.. It just doesn't have internet and can't really communicate with the gateway.

EDIT#2: It has to be an OPNSense issue, because just for a test I gave it a gateway of our backup Ubiquiti Dream Machine and it kept pinging google without issues throughout the migration and after.


EDIT#3: Just noticed that the migrated machine can't talk to any other machine inside the cluster. And as OPNSense is also a VM in the cluster, it has to be an issue with Proxmox Networking and I have to investigate there now.

[weidah]

Figured it out. It's a bug with SR-IOV, where the virtual bridge that has the Virtual Function of the SR-IOV won't forward anything until you manually set the bridge forwarding database to include the virtual NICs.

I've already had a script do it for the machines on boot and when I migrated to the other host it I would have had to do it there also. Unfortunately I haven't come across a way to hook it to trigger on migration.