The default gateway address does need to be your roommates computer interface ( The one you connect to or that connects to the LAN. ) You can check this with the route command:
ex: /sbin/route. the last line should look like:
default 192.168.0.1 0.0.0.0 UG 0 0 0 eth0
Does ifcofig show that the NIC interface has an IP address? If so, then either you set it up manually or you have access to a DHCP server through your roommates computer. You can run "/usr/sbin/ifconfig eth0" to check if it does.
The first two lines of output should look similar to this:
Code:
eth0 Link encap:Ethernet HWaddr 00:17:31:AB:78:A9
inet addr:192.168.1.102 Bcast:192.168.1.127 Mask:255.255.255.128
Now I'm not certain how windows does network sharing. What is your roommates WAN side IP address? If it is someting like 192.168.0.xxx then there may be a problem because his two interfaces may be in the same subnet. I did something similar once where my desktop didn't have a wireless interface but my laptop did. So I used ip forwarding to gain access to the internet. Both computers were running SuSE Linux. I had the wireless device in the 192.168.1.0/255.255.255.128 subnet and my desktop, and printer were on the 192.168.128.0/255.255.255.0 subnet. If your roommate has an interface with an internet address ( not a private one like 192.168.xxx.xxx or 10.xxx.xxx.xxx, etc ) then there probably isn't a problem.
Another thing to look for is the nameserver addresses. If you are configuring your interface manually, then you may need to get those addresses from you roommate. ( He can get them in the device properties configuration, or by entering "ipconfig /all". These address are needed in /etc/resolv.conf. Take a look at your /etc/resolv.conf file and see if they are there. Using dhcp this will be filled in. One trick is to set up your computer first for dhcp and record your ISP's nameserver addresses. Then add those address to /etc/resolv.conf when you configure it for static addressing. Sometimes, if you want your computer to function as a server you will want a static address.