I have been running my network off a cheap Linksys Router for a few months, and now with the long weekend I had some time to setup my own router/nat box.
The OS for the router/nat box is OpenBSD 3.7 with two network cards installed. I was able to get both installed and running but I am having trouble "getting out" from the workstations when the Linksys router is removed.
When I have the setup going from the Cable Modem -> External NIC on the OpenBSD box (dc0), then from the Internal NIC (dc1) -> Switch -> Workstations, I can not ping the dc1 IP from any workstation. I can SSH into that IP though (don't understand why). The workstations can ping each other too.
When I change the setup to include the Linksys Router inbetween the Cable Modem and the dc0 NIC on the BSD box, it all works? I can ping anything internal and on the web. In this setup, ifconfig shows the default IP scheme used by the Linksys Router for the dc0 NIC, which is "192.168.1.100".
In both cases, I have the workstations pointing to the BSD box for the default gateway. Manually entering the DNS numbers provided by the ISP (comcast.net in this case). Also, in both cases the OpenBSD box can ping all the workstations, and ping outside the network as well.
My pf.conf log has the following line in it:
nat on dc0 from dc1:network to any -> (dc0)
...which from my understanding, should allow everything to pass (just want to get it all working before I even try to "lock it down").
I am giving up on it tonight and will try some more tomorrow. Am I setting some of this up incorrectly perhaps (ok Im sure that I am, haha). Any configurations that would help I can post, and any clarification needed just ask.