We've started encountering an issue with iptables on our RHEL 6.3 systems in that after a reboot, when the service starts, the rules are not loaded. We get the empty ruleset:

[msnyder@matt-test ~]$ sudo iptables -L
Chain INPUT (policy ACCEPT)
target     prot opt source               destination         

Chain FORWARD (policy ACCEPT)
target     prot opt source               destination         

Chain OUTPUT (policy ACCEPT)
target     prot opt source               destination 

This is in spite of the fact that we have rules defined and the service is, indeed, running. That I know because when I run service iptables start it simply drops back to the prompt. If I run service iptables restart it actually stops and then restarts the service. And, of course, if I run service iptables stop it indicates that iptables is actually stopping.

Knowing that I need to restart the service, I do so and the rules load up properly. They simply don't get loaded after a reboot. Unless they get loaded differently during a reboot I don't see how our rules would be wrong. If they were, they wouldn't even load during a service restart.

Has anyone else ever encountered this?

EDIT: The rules are already saved in /etc/sysconfig/iptables. They are not added on the fly from the command line so service iptables save is unnecessary.