Hi, I'm about to setup ISP in a multiserver setup. For this I'm going to follow this guide. I am troubled with the ISPConfig firewall. It either blocks ports or it allows ports. It is also not clear to me how the firewalling is done. Is it using iptables or another means? I need to setup very specific rules. Example: The mysql server only needs to talk to servers in the setup, and not to any other servers or clients requesting access or trying to force access. So I want to allow port 3306 only to the servers I specify. Perfectly possible in IPtables, but not in the ISPConfig firewall. Does ISPConfig use IPtables? If yes, does ISP config overwrite the existing rules or make additional rules? If no, what system does ISPConfig use, and can I make changes outside of ISPConfig? Would it be better to disable the ISPConfig firewall in order to achieve my goal, or is there a convenient work-around?