I have a fresh installation of OMV 2.0 and tried to setup a firewall, but from console.
So I apt-get install ufw and set some basic rules:
ufw allow ssh
ufw default deny incoming
ufw default allow outgoing
Everything was working normal, but after reboot, there was no internet connection. I had to login to console and disable firewall - then it started working.
I also tried with iptables from console:
iptables -A INPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -p tcp --dport 22 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -I INPUT 1 -i lo -j ACCEPT
iptables -P INPUT DROP
iptables -A INPUT -j DROP
Again - everything is working fine, but after reboot, no internet from the machine.
In fact, I am using OpenVPN client on the device, and since there is no internet, it cannot login. After I say iptables -L, openvpn connection is established normally.
It seems something is disabling internet when I set up firewall manually... maybe OMV is interfereing with comman-line firewalls in some way?