After spending 4 hours, I found that doing; /sbin/bastille-netfilter stop made outgoing mails sent and dns resolve worked fine. I am new to ispconfig. Where do I control firewall? In system setting I tried enabling firewall and added all needed port but after just /sbin/bastille-netfilter start then outgoing mails and dns issue comes back again. What do you suggest? I am not sure if /sbin/bastille-netfilter default state is start or not.