Mandrake 10.0 network problem

Hi, yes, I'm NewB to Linux, but not to cimputer. I'm trying to configure both network card, to share my internet connection. I can configure the NET card (the card used to go on internet) but, when I configure the other card (I'll call it LAN) I loose connection to Internet, but I STILL have my IP adress. I tried a few thing, but it never work, and sometime after setting the LAN card, the system decome extremly slow (It can take up to 5 minute to open a console) *PS: I'm on a P4 2.6Ghz* But it doesn't append everytime. I made a route -n BEFORE and AFTER setting the lan card, to see if there is any trouble, I'll past the result here
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Destination||||||Passerelle||||||||Genmask|||||||| Indic|||||Metric||||||Ref||||Use||||||Iface
66.131.219.0|||||||0.0.0.0||||||255.255.255.0||||| ||U||||||||||||0||||||||||||0|||||||||0|||||||||et h1
127.0.0.0||||||||||||||0.0.0.0||||||||||||255.0.0. 0|||||||||||U||||||||||||0||||||||||||0|||||||||0| ||||||||lo
0.0.0.0|||||||||||||66.131.219.1|||||||||0.0.0.0|| |||||||||UG|||||||||||0||||||||||||0|||||||||0|||| |||eth1


AFTER
Table de routage IP du noyau
Destination|||||||Passerelle|||||||Genmask|||||||I ndic|||Metric||Ref||||Use||||Iface
66.131.219.0|||||0.0.0.0||||||||255.255.255.0||||| U||||||||||0||||||||0|||||||||0||||eth1
192.168.0.0||||||||0.0.0.0||||||||255.255.255.0||| ||U||||||||||0||||||||0||||||||0||||eth0
127.0.0.0||||||||||||0.0.0.0|||||||||255.0.0.0|||| ||||||||||U|||||||||||0|||||||0||||||||0||||||lo
0.0.0.0|||||||||||||||192.168.0.1|||||0.0.0.0||||| |||||||||UG|||||||||0|||||||0||||||||0||||eth0

Sorry for those ||||||| it seem that I can use more than 1 "space"
Please help me
thank you!
Alex

I'd suggest instead of using pure iptables, you use a front end like FireStarter or Shorewall. If you use the internet sharing wizard in the MCC, then you'll be setup to use Shorewall with a transparent proxy through Squid. That can be a bit daunting to maintain or even understand and is definitely intended for use in a large environmet. Firestarter is nice for a small home network, and there are Mandrake RPM's available. Firewall is very easy to setup, configure, learn and maintain.

Hope that helps!
Jeremy