Hi. I use Proxmox 4.3-1 version. early I created iptables firewall and used it on lots of servers. There are some rules and the bottom lines are like that :
-A INPUT -j LOG_DROP
-A LOG_DROP -j LOG --log-prefix --DROP--:
-A LOG_DROP -j DROP
It's very easy. I use it on LVM that is on proxmox...