Just got my first Mac. It is a powerbook with OSX 10.3 on it. Im trying to make the ip_forward function work just like ive been able to do with my other laptops and any version of linux i've ran. I soon found out that the command to enable the ip fowarding feature is "sudo sysctl -w net.inet.ip.forwarding=1" but it doesn't seem to work like im used to. I have the laptop (192.168.1.107) connected to my network with a linksys router (192.168.1.1) and a XP desktop (192.168.1.100). I set the default gateway of the desktop to the ip of the laptop and am trying to get the laptop to farward any packet it receives that isn't for itself to be farwarded to the router....i think that makes sence...if not i'll try to re-word it.

what am i missing...is a firewall blocking it? i have the firewall disabled in the gui. And this is a fresh install.

How are you connecting the desktop and laptop? If they're all connected to the same switch, the Mac laptop is probably just issuing ICMP redirect packets back to the PC desktop since it can reach the gateway on it's own. If you have an additional network card, then how did you set that up?

All the systems are connected through the same switch. There is only one nic in the mac. Is there a way around the ICMP redirect packets, this was so easy to do with linux, i can't imagin that it cant be done. The PC could access the gateway on its own, but i want to route the info through the mac so that i can play with tools like snort without having to have a hub between, or haveing two nics. I can't install linux on the PC because of work related programs that need windows. anyway to do this with a mac?