Firewall on Fedora how it works, and runs by default

[Antonio Olivares]

Dear fellow fedora users,

In light of the antivirus questions/issues, Fedora comes with a firewall that runs by itself after installation? 

I know there's system-config-firewall, and 

http://fedoraproject.org/wiki/SystemConfig/firewall

but I don't know actually how this works :(, I know that somethings are allowed and others are not, I don't know if the iptables is started at the beginning and how it works.  If the network one is on is ipv4, we have one thing, and we also have ipv6 and there is a different thing right?  I also see this :

ip_tables: (C) 2000-2006 Netfilter Core Team
nf_conntrack version 0.5.0 (16384 buckets, 65536 max)
CONFIG_NF_CT_ACCT is deprecated and will be removed soon. Please use
nf_conntrack.acct=1 kernel parameter, acct=1 nf_conntrack module option or
sysctl net.netfilter.nf_conntrack_acct=1 to enable it.

I have been happy with the default setup, but I don't know how it works.  I know other distros don't enable the firewall by default, but Fedora does.  Is there any howto, or other documentation of what really happens behind the scences.

Thanks in Advance,

Antonio