Linux – Can’t disable firewall on CentOS 6.3

CentOS firewall and iptables are the same thing. Refer to this documents.

You can control iptables from command line or by using the GUI interface which is "Security Level Configuration Tool", the one you are using it from the menu.

By default, the firewall is enable during your setup. The setup interface will recommend it and it will block all traffic, unless you specifically allowed it.

For starters is ssh running on a custom port?

Secondly, can you post a copy of your iptables ruleset, and a description of the gui interfaces set.

to list iptables:

iptables -L -n -v

Update:

It looks to be a number of things, one is the addition of fail2ban. Not to mention that system-config-securitylevel configures the firewall in a very specific way, anything outside of this exact setup is going to cause it to not recognize those services since it's not configured the same way. That's the reason for the difference, and to be expected.

What is listed in iptables are the rules that are in effect. Regardless of what system-config-securitylevel states, iptables -L will always show the existing and active ruleset.