On 01/04/2013 03:03 PM, Dale Dellutri wrote: > On Fri, Jan 4, 2013 at 11:01 AM, Tim Evans <tkevans at tkevans.com> wrote: >> I'm replacing an ancient Solaris 'ipf' firewall/router with a brand new >> CentOS 6.3 system. In the olden days, I successfully used the attached >> iptables script (as /etc/rc.local) on Red Hat 5.x systems, but this doesn't >> seem to be quite working on the new system. >> >> Specifically, while it seems to be routing ok, you cannot connect to >> anything on the inside net (e.g., with ssh or a browser) and cannot connect >> to the system with ssh or anything else from elsewhere on the inside net. >> Yet arp shows this system active. >> >> Is there obsolete stuff here, and/or anything missing that would cause this? > > You found the error, but I have a question about running this in rc.local. > > Aren't you opening a very short time security hole by running this from > rc.local? Service network starts up early in the startup sequence > (/etc/rc.d/rc3.d/S10network), and rc.local is at the very end. > > Wouldn't it be better to run the iptables rules once, then do: > service iptables save > This way, iptables rules would be in place (S08iptables) before > netowrk startup. > Thanks, Dale. I'm trying to remember why I did it this way (nearly 10 years ago, when I did this first.) Seems it had to do with not turning on routing until the very end (instead of enabling it in /etc/sysctl.conf), relying on the out-of-the-box iptables rules in the interim (iptables still starts normally). This script overlays its rules, then turns on NAT and routing. -- Tim Evans | 5 Chestnut Court UNIX System Admin Consulting | Owings Mills, MD 21117 http://www.tkevans.com/ | 443-394-3864 http://www.come-here.com/News/ | tkevans at tkevans.com