I have been using ConfigServerFirewall with Ispconfig3 on Ubuntu and it is working perfectly and it is more secure and supported, if its not please feel free to comment
How to install:
Quoted from their file:
Installation is quite straightforward:
rm -fv csf.tgz
tar -xzf csf.tgz
Next, test whether you have the required iptables modules:
Don't worry if you cannot run all the features, so long as the script doesn't
report any FATAL errors
You should not run any other iptables firewall configuration script. For
example, if you previously used APF+BFD you can remove the combination (which
you will need to do if you have them installed otherwise they will conflict
That's it. You can then configure csf and lfd by edit the files
directly in /etc/csf/*, or on cPanel servers use the WHM UI
csf installation for cPanel is preconfigured to work on a cPanel server with all
the standard cPanel ports open.
csf installation for DirectAdmin is preconfigured to work on a DirectAdmin
server with all the standard DirectAdmin ports open.
csf auto-configures your SSH port on installation where it's running on a non-
csf auto-whitelists your connected IP address where possible on installation.
You should ensure that kernel logging daemon (klogd) is enabled. Typically, VPS
servers have this disabled and you should check /etc/init.d/syslog and make
sure that any klogd lines are not commented out. If you change the file,
remember to restart syslog.