forward chain

Hi there I've noticed a change between two proxmox versions. In newer ones , no traffic is passing through the FORWARD chain (.e.g iptables -L FORWARD -vxn shows 0 packets 0 bytes) proxmox-ve: 5.1-38 (running kernel: 4.13.13-5-pve) pve-manager: 5.1-43 (running version: 5.1-43/bdb08029)...