Just to clear the air, let me first for-warn that this leans a little more heavily on the computer-related than the computer-science... Though I am currently working towards a degree in Computer Science, not that that holds much pull in regards to my post's validity!

That aside, I have a network configuration question/puzzle. Here's the layout. I've got a desktop computer running Windows XP, and a laptop running Windows Vista. the desktop has two ethernet ports (one built into the mobo and another seperate ethernet card), one of which is connecting the desktop to a greater network via a standard Cat-5, while the other has a Cat-5 crossover cable plugged into it, the other end of which is plugged into the laptop.

Now, I've manually configured both computer's connections to one another to have compatible IPs and subnet addresses (via IPv4). They can see eachother talk with one another, and share files and the like just fine. My dilemma is in that I wish for my laptop to connect to the internet through my desktop's other connection. The systems' connection to one another must be defined with IPs incompatible with the IP that my desktop receives from the broader network for, if the broader network receives any connections from unathorized IPs, things start getting real buggy real fast (please pardon my hazy description - I will happily answer any clarification questions that you might ask!).

So, in an effort to solve this issue, I went into the properties for the ethernet adapter on the desktop that managed the connection to the laptop, and enabled internet connection sharing. On my laptop, I entered the IP address of my desktop. I believed that this was all I needed to do, yet it seems to no avail - my laptop still is unable to connect to the internet. To better (hopefully better, anyway) illustrate my current configuration, here is an artist's MS Paint rendition:



So in essence, I need the internet traffic from my laptop to be funneled to the greater network through my desktop's IP.

Thanks in advance for your help!
~KuroTsuto

P.S. I did try "Bridging" the connections once before, but the greater network really didn't like that all that much.

Why not just buy a router for ten bucks, an extra length of cat5 for four and call it good? Hell buy a wireless router for twenty and be done with it?

You need to search for 'turning a pc into a router'.

INternet Connection Sharing has never been a really fun topic for me. I tried several configurations on my local network to try to do something similar but had nothing but headaches out of the whole mess.

One thing you might try.. there is an ICS Wizard in windows.. assuming you are running windows, you can run, it tries to configure the computer correctly automatically. You might give that a try if you haven't already.

Here is the official microsoft article on it:

http://support.microsoft.com/kb/306126

Aet

Hey guys,
thanks for the quick replies, and please pardon the tardiness of my own (midterms and such).

@modi: a supply of hardware has indeed been readily available. However, said hardware on hand conflicts with the configuration of the greater network, and I came to the assumption that it would be much easier to troubleshoot a simple connection between two computers where I have a large amount of control than to attempt to do the same in an environment with hardware over which I have little to no control.

I did go ahead an research the straightforward "turn comp into router," approach, but it really only returned with linux solutions, which I am not currently interested in.

@Aet: ICS is unquestionably something of a mess and really isn't all that well documented for how often it must come up, agreed!

I had given the wizard a try, but it seems to me as though M$ made the thing a little too user friendly, completely obscuring what it was actually doing and, in my scenario, actually proving to be slightly MORE confusing than manual configurations.


But in any scenario, I did a fair amount of research and came back knowing much more than what I started with. There are a few plausible solutions to my issue:
-Use NAT software on the desktop. ICS is actually a form of NAT that comes standard on Windows, but there are more user-friendly alternatives
-Use a proxy server on the desktop such as WinGate

I kept tinkering with my configurations, and eventually I must have accidentally un-done something I did earlier, for an option for Internet Connection Sharing reappeared for Adapter2 on the desktop. Enabling this set Adapter1's IP to 192.168.0.1 and further bound a NAT to Adapter1 so that every computer connecting through the adapter would be automatically assigned a 192.168.0.x address.

Thanks for you guys' help!
~KuroTsuto

Glad it worked!
I looked at the ICS documentation and was kind of wondering if your IP configuration was going to allow you to assign the required 192.168 IP's to the sharing computers. I thought you might have some pre determined business rules that required you to use the odd IP's I saw in your diagram.

Great job getting it sorted!
Aet