Bypassing an Anti-Router Network Connection

This topic is only indirectly related to Game Development, but I thought by sharing this you may be able to overcome some frustrating network difficulties and get back to game development.

Let me state first that I worked for a University IT department for almost seven years, so understand that my criticism is not directed at the individuals who implement the technology, but instead at those who make the near-sighted policies. (Even if the IT drones themselves are too spineless to stand up against said policy makers.) But I digress.

The problem is that the new trend with University internet connections is that the IT departments (in their infinite wisdom) have decided to prevent you from placing a router between their network connection and your computer. The reasoning is that they do not want you setting up or paying for only one connection, and then sharing that connection with other people.

The old way of accomplishing this was to restrict the connection to the MAC address of your computer. Of course, the easy way around this is to use a router with software that fakes the MAC address.

Oh, but now they are so much more clever. They have some fancy software at the University that detects routers, and shuts off the connection automatically if finds one (I’ve experience this first hand). But before I discuss how easy it is to get around this, let me present a few honest reasons for wanting to have a router.

  • You’re having a study session. Your classmates bring their laptops and want to research online. (After all, that’s where the University is putting all their resources these days!!)
  • You use your router to connect to various external devices (printer, external hard drive, etc)
  • You have more than one computer! Which is really not that unusual anymore, especially for computer programmer students.
  • You use your router for networking to video consoles (PS2, PSP, PSP, Xbox, Xbox360)

  1. In my case, my course work requires that I program on the PS2, which needs a wired network connection. Not only do I need to telnet to my PS2, I also need to use Samba to access the filesystem.
  2. I have an external hard drive that is connected to my router.
  3. I want to purchase a single wireless network printer that I can share with my flatmates.
  4. And finally, I really wanted my friends to be able to connect to the internet when we are working on group projects … I don’t want to be the guy who has to look everything up and then transfer it by USB stick.

A few notes about my solution:

  • My PC has to be turned on and connected for this to work. My PC is the DHCP server, and without it the connections are lost. You could manually enter the IP addresses for all the devices that want to connect and this would allow you to have intra-network connection (but not internet) while the main PC is off or disconnected.
  • If you are wanting to do network gaming, there still may be blocked ports … which you’ll have to address separately.

So without further delay, here is my solution:
ICS-setupThis is the one time when I really am impressed with Microsoft… Internet Connection Sharing (ICS) works great for this. I connect my computer to the University’s network via Ethernet cable, then I share my Ethernet connection with my wireless connection. (Click on the image to see the settings.)

This works with both Vista and XP. I know, because I have a dual boot … and everything works fine no matter which OS I’m booted into.

Now this is where it gets a little crazy. I replaced the software on my Linksys Wireless-G Router (WRT54G) with DD-WRT. I then connect my computer to my router with the WiFi connection. The Router is set only as a “Gateway” (only the significant settings are listed):

Basic Setup
Internet Connection Type: Disabled
Local IP Address: 192.168.0.100 (With ICS, your computer’s shared connection is 192.168.0.1 by default)
DHCP Server: Disabled

Advanced Routing
Operating Mode: Gateway

Wireless – MAC filter
I use the MAC filters for the wireless connection. This is a personal preference but I feel it meets my balance of convenient with security.

Then my friends can connect directly to the wireless router.

MyCrazyNetwork
My Crazy Network


Thats it. I hope it helps you, because it certainly has helped me.

You might also note that in order to get the PS2-DevKit Samba working on Vista there are a few settings that you need to modify in Vista. And if you don’t want to bother with Samba, you can always just FTP files back and forth from your PS2.

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