Why does it have to be CentOS? If you want a wonderful router/firewall that you can have up and running in a few minutes, you should look at this: www.pfsense.org I quote from their website: "pfSense is a free, open source customized distribution of FreeBSD <http://www.freebsd.org> tailored for use as a firewall and router. In addition to being a powerful, flexible firewalling and routing platform, it includes a long list of related features and a package system allowing further expandability without adding bloat and potential security vulnerabilities to the base distribution." If you insist in using Linux instead, you could look at this: www.ipcop.org Once again, a distro specialized on the function it performs. Why have a generic and bloated system that you then have to customize from scratch when such wonderful specialized projects already exist? I use Linux servers and a pfsense firewall to protect the network. Works like a charm, with amazing stability and reliability.