Actual problem: No traffic on my bridge network to virtualized firewall. Network setup related to firewall, see also interfaces config file: virtio net0 <-> vmbr1 <-> eth1 <--> WAN virtio net1 <-> vmbr0 <-> eth0 <--> LAN, Wifi, Clients and VMs all on the same network, no DMZ What happened before: This server with zfs root was running out of disk space. This affected the kvm VMs to struggle, especially the virtualized pfsense firewall was not operating properly anymore. I freed up some space and was able to restart this VM and networking was working as expected again. For some reason I decided to reboot the whole machine, before that I ran an update on the proxmox host: apt-get update && apt-get dist-upgrade From the log file Start-Date: 2017-12-06 22:31:10 Commandline: apt-get dist-upgrade Install: pve-kernel-4.13.8-3-pve:amd64 (4.13.8-30, automatic) Upgrade: libpve-storage-perl:amd64 (5.0-16, 5.0-17), pve-qemu-kvm:amd64 (2.9.1-2, 2.9.1-3), pve-ha-manager:amd64 (2.0-3, 2.0-4), pve-firewall:amd64 (3.0-3, 3.0-4), pve-cluster:amd64 (5.0-15, 5.0-17), vncterm:amd64 (1.5-2, 1.5-3), spiceterm:amd64 (3.0-4, 3.0-5), pve-manager:amd64 (5.1-36, 5.1-38), libpve-common-perl:amd64 (5.0-20, 5.0-22), lxc-pve:amd64 (2.1.0-2, 2.1.1-2), libpve-http-server-perl:amd64 (2.0-6, 2.0-7), proxmox-ve:amd64 (5.1-28, 5.1-30), lxcfs:amd64 (2.0.7-pve4, 2.0.8-1) End-Date: 2017-12-06 22:32:36 Since then I can't get any traffic (not even ping) from the clients to the firewall or vice-versa. Also the firewall is unable to get an IP from the WAN over vmbr1. I can not login from a client on the LAN network to the pfsense host, however it works from within proxmox over ssh: client <-> proxmox host <-> pfsense I can also use w3m to connect to the web interface of pfsense, so the wm seems to work fine. I checked the hardware tabs of the pfsense VM and they show the correct network interfaces, so nothing has changed there. Any ideas? How could the reboot have messed up things? I don't think that it's related to the updated packages above, as those are all minor updates. I'll try the following: - Communication between LXC containers that are also using vmbr0 - Setup a new kvm machine on vmbr0 and vmbr1 and check whether that works Thanks in advance for your help!