Sorry to re-open this long and old thread, but, even if there's still no agreement on a potential Firewall SIG, I'd like to receive comments from experienced CentOS developers about the work we did trying to simplify (if possible) a firewall interface. Those interested could quickly try a demo (hosted or using docker): http://www.nethserver.org/demo-running-on-docker/
After log in, head to Firewall rules (and objects).
Known problems: leaving the page without firewall rules ask to confirm (it's a problem of the docker demo)
Please, let me know your opinions.
As you can see, I'm still interested in creating a SIG centered around using CentOS as a firewall. :-)