Do you have any idea about a firewall software that it's capable to maintain multiple Linux machines via a web interface (or GUI)? I created myself such an application, but it's far from being usable on large scale. So I was wondering if there is any application that can store all firewall rules on one server and every server can start its firewall based on the rules located there. Also, a GUI would be a bonus.
Thanks.
In some ways, what you're trying to do is impossible. Since - to avoid a dangerous window of vulnerability - most distros bring up the firewall rules before they bring up the network interfaces, it's prima facie impossible to get the firewall rules over the network at boot time.
Once you accept that, you've redefined the problem as "how do I centrally maintain the configuration file(s) that control firewalling", and that leads naturally to centralised admin tools like Chef and Puppet.
Neither of those is specifically for writing distributed firewalls, so neither has a GUI in the sense the you're after one. But I, like others, would recommend that you continue to maintain your firewalls by editing the actual config files; the work of distributing them out to the many nodes can be minimised with one of the tools above.
You should have a look at fwbuilder. There is a client for Linux and Windows. It can handle Linux FW, Cisco, BSD etc. Its easy to use - though it hasn`t a webinterface…