Q:

How to re-enable iptables on Fedora 18?

FirewallD is the default firewall in Fedora 18. I have been using iptables  for quite some time and have a custom configuration which I need for logging of ip traffic. I am not used to the new graphical interface which seems to lack many of the functionalities present in the old one, that can be loaded with ease. 
I tried to re-enable the old iptables with the following commands:
# systemctl stop firewalld.service
# systemctl start iptables.service
# systemctl start ip6tables.service

The messages log shows:

systemd 1 Started IPv4 firewall with iptables. 
  systemd 1 Started IPv6 firewall with ip6tables.

But from systemctl -t service -a, I can see that both remain inactive and dead, despite being loaded.
Nevertheless, I tried loading the custom configuration with 
iptables-restore < iptables.conf

but got a series of warnings:

WARNING: The state match is obsolete. Use conntrack instead.
  WARNING: The state match is obsolete. Use conntrack instead.
  WARNING: The state match is obsolete. Use conntrack instead.
  WARNING: The state match is obsolete. Use conntrack instead.
  WARNING: The state match is obsolete. Use conntrack instead.

What should I do to get iptables back to work?

A:

Looks to me like that is because of a new version of iptables that came out in October. -m state --state has been obsoleted in favour of -m conntrack --ctstate.  Hence, "The state match is obsolete. Use conntrack instead."
http://forums.gentoo.org/viewtopic-t-940302-start-0.html
http://blog.yjl.im/2012/11/iptables-state-match-is-obsolete-use.html
'conntrack' is in my man page (1.4.14, which is not the newest one):

conntrack
         This module, when combined with connection tracking, allows access to the connection tracking state for this packet/connection.
[!] --ctstate statelist
                statelist is a comma separated list of the connection states to match.  Possible states are listed below.
[...]
States for --ctstate:
INVALID
       meaning that the packet is associated with no known connection
NEW    meaning that the packet has started a new connection, or otherwise associated with a connection which has not seen packets in
  both directions, and
ESTABLISHED
                meaning that the packet is associated with a connection which has seen packets in both directions,
RELATED
                meaning that the packet is starting a new connection, but is associated with an existing connection, such as an FTP data
  transfer, or an ICMP error.
[...]

Thanks for the heads up on this, BTW.

