Ipfilter trouble

Hello I need some help with ipfilter. I don’t know much about NAT and I am trying to set it up for some windows and unix clients on my home lan to connect to the internet sharing the same registered ip.
The main problem seems to be that when I try to enable ip-forwarding with the command “io-net -p tcpip forward”, the network interface (en0) disappears.
Beside that, some manpages seem to state that I need to create another interface (en1), for the internal network, but I have no idea how to do that.
Also, I am not sure how to configure the windows2000 clients for nat. I gave them an ip address from the range I specified in nat.conf, and put the en0 internet ip of the NAT box as default gateway. What about the netmask?
Any help on this would be greatly appreciated.

First of all, you need a “gateway” in you home lan, which means, you need a machine have 2 network cards, one for the
internal network, one for the internet connection.

The proper command is to bring up the io-net like “io-net -d -d -p tcpip forward”, please note in a
common installation, io-net is ALREADY started for you before you see a login prompt, so you want to kill it first by
“slay io-net”.

Then you need to config your 2 interfaces, the one connected to “the world” is depends on what is your ISP says.

After that, we are now into the IPFilter loading, NAT/Filter config business.

For you last question, your w2k machine on “internal” lan, could either manually configured to on your internal
sub-net (cause NAT will handle any node on a subnet); or, if you wish, you can config/start dhcpd on your
gateway QNX box, to allow all internal box be dhcp.

Thanks that was a great reply. Helped alot. I’ll set it up in a few days I’ll let you know how it goes.
The the QNX gateway connects to the provider’s dhcp, do I need to start my own dhcp server for the internal lan, or do I just map the internal ips to the address given by the provider’s dhcp?

Since your ISP do dhcp, so you need to start dhcp.client on the QNX gateway to config the outside ether interface.
(en0 or en1), do a “use dhcp.client” to see how to specify an interface to dhcp.

For you internal network, you need to manage it yourself. The easiest is manully set every one if you
don’t have too much on LAN. Set your gateway’s internal interface 10.1, and then 10.2, 10.3 … on LAN.
Every internal box need to have a default route to 10.1 (your gateway box), and they need to have a
DNS point to what ever come from your ISP. Once the manual stuff works, you can consider to move
to a dhcp server to allow all internal box works on dhcp.client

I installed two network cards, but it looks like qnx is switching one off at boot. They are both using the same ne2000 driver (one is via-rhine, but only works with ne2000), and I think that’s the problem because when I try to start io-net or mount the second network interface it tells me that the device is already started. Maybe I am using the wrong syntax?
#slay io-net
#io-net -dne2000 -dne2000 -ptcpip forward
I have also tried
#mount -Tio-net /lib/dll/devn-ne2000.so /dev/io-net/en0
#mount -Tio-net /lib/dll/devn-ne2000.so /dev/io-net/en1

Thanks again for your help.