Currently, there's little help from the threads I've read on this subject.

I have a Mandrake box with two cards, and a Windows box. Connected by crossover cable, all fine. When the Mandrake computer is booted into Windows, Internet sharing goes fine. Not so when running Mandrake.

The Mandrake box:
eth1, connected to Internet through a gateway, static IP, properly configured.
eth0, 192.168.1.26, connection to the Windows comp

Windows comp:
192.168.1.2, and does have 192.168.1.26 as its gateway setting. As said, net here works when the first comp is booted into Windows.

I updated Shorewall (heard that the one Mandrake 10 ships with is buggy), and I set up iptables - when booting, I get the "Starting IPv4 packet forwarding" message. Pings travel fine between the two computers both ways. However, the Windows comp can't access the Internet. It does resolve names to IP addresses, but it doesn't go any farther than that. A traceroute to any site stops after succesfully reaching the Mandrake box.

I assume there's something wrong in either my iptables or shorewall config that doesn't let the Windows computer's packets be passed on to the Internet, and that prehaps routing only works one way - from Mandrake comp to Windows comp, but not the other way around. Any ideas or areas where I need to elaborate?

Much appreciated!

What's in your /etc/resolv.conf?

Here:

nameserver 193.111.244.10
nameserver 193.111.244.3
nameserver 127.0.0.1
# nameserver 192.168.1.126

# ppp temp entry

The first two are my ISP DNS servers. Should I outcomment the last line?

However, I think that DNS works. When I load up IE on Windows box, it says there, connecting to somesite.com, then connecting to xx.xx.xx.xx, where that IP is IP of the site. Also a tracert on somesite.com shows it able to resolve that to an IP.