Hello, I have a very annoying problem regarding a small network i made using my laptop and another old machine. First of all i can assure you that there is nothing wrong with both LAN cards, they work perfectly. Now the thing is, I have Windows XP SP2 on my laptop, and Ubuntu Server Edition on the old machine (this ubuntu version has command line only). I connected both machines on my ADSL2+ modem (Model: Zyxel P-660HW-D1) so i can use the old machine as a server but here is a were them problem comes. At first both machines had the same IP Address (88.112.24.233) but the internet worked on both machines (I used a 16-bit browser called lynx to check WhatIsMyIp.com on the linux machine) then i went into my zyxel modem configuration page to check whats going wrong (using 192.168.1.1) then i saw that DHCP was turned on, and NAT is working and both machines are obtaining an IP quite normally. I then notice that the zyxel help page said if i have more than one public WAN IP, i need to turn NAT into "Full Feature" mode instead of "SUA only", since i did have 2 machines i did so but then windows informed me that there has been an IP Conflict and after that the internet did not work at all. What i'm trying to do is simply fix this IP Conflict but i haven't been able to for a week! Here is some info i took from my modem configuration page just incase you might need it (Pictures): http://i23.tinypic.com/2nal5e8.jpg http://i23.tinypic.com/2mmwbox.jpg http://i20.tinypic.com/4g24w4.jpg

I recommend investing in a router. This will make your life much easier, and more secure. They are very cheap at Staples. "Computer security." — Oxymoron

Well i have an ADSL2+ Modem, why would i need a router? I'm not sure if this modem acts like one but it would be much more of a hassle... I'm sure there's a simple solution for this problem but i can't seem to find it.

You can't have two machines with the same ip address. Its a prime rule of tcp/ip. My guess is you used a web site to check your ip and thought it was the workstations when in fact it was the routers wan ip. This is because your pcs are hidden from public view via your router. You don't have two wan ips from what you write so set back to sua [single user address]only. Are you ready for where Microsoft wants you to go today?

ADSL2+ has nothing to do with what a soho router is or can do to help. Hassle maybe, security improvement yes if setup correctly. How are you able to connnect two devices to that modem? Why not use ipconfig and ifconfig to tell what the lan ip is? It could be that if you turn them on and off in the right order and some other settings occur then one machine may not release the IP address. (this assumes that your wan ip is at the machines). Could be as above that you are seeing the modem's extenal ip. Not knowing enough about ADSL2+, I guess that there could be some oddity of the design. Dunno how they exactly get twice the speed. For it to work correctly it should not have two exact ip address on the same segment. I read it wrong and answer it wrong too. So get off my case you peanut.

You diagnosed the problem yourself: "I then notice that the zyxel help page said if i have more than one public WAN IP, i need to turn NAT into "Full Feature" mode instead of "SUA only", since i did have 2 machines i did so but then windows informed me that there has been an IP Conflict and after that the internet did not work at all." Your connection was working before you made the change, you made the change, the connection stopped working. Your provider only supplies 1 IP Address. Duh! Your ADSL2+ modem has an internal router that prevents collisions between the packets from each client. If it had 2 WAN side channels it would split the routing between these, effectively doubling your potential throughput. However unless you d/l a lot of binary files on both machines simultaneously you wouldn't really notice the difference. Either buy a 2nd IP address (usually around $5/mo extra) or revert your settings and don't worry about it.