On Thu, 23 May 2002 18:01:03 EDT, "Steven J. Sobol" said:
The box I want to build is passing packets between the rest of my network (and the public Internet) and one server that will hold sensitive data. It'll be a Linux box with the TCP/IP stack running in bridged mode, with two ethernet adapters installed. The box just needs to boot up and run. It doesn't need to log anything.
I've heard tell that a good way to secure a Linux box that's doing this is to have it boot, set up the interfaces, set up iptables, and then do a quick /sbin/halt - if you fail to 'ifconfig down' the interfaces on the way down, the kernel will happily forward the packets while being immune to exploits (since there's no processes running anymore). I haven't tried it, so I dont know if it works. Maybe there ARE cases where setting the default runlevel to 0 or 6 make sense. ;)