P2P Testbed Information

Ian Fung (if26) and I (dsc29) had finished the testbed is setup in Rm 330 of the CSUG Lab. The diagram below illustrates its topology. The design was mostly done so that there is least amount of re-wiring of the existing workstations. So as a result, our private/inside network is actually implemented over the existing CSUG LAN, except it uses the internal address space of 192.168.0.x and must go through the NAT boxes to contact any machine out of this internal subnet.

Some info about testbed

With two NAT boxes, we could emulate having two internal networks. We do this by partitioning the 192.168.0.x address space into two equally big subnets. The NAT boxes' private (inside) addresses are static and are 192.168.0.1 and 192.168.0.129 for each subnet. Their global addresses (or outside addresses) are also static.
To configure a client to be on the Subnet 1, choose an address in from 192.168.0.2 to 192.168.0.126. For Subnet 2, choose from 192.168.0.130 to 192.168.0.254. The corrsponding subnet mask for both subnets is 255.255.255.128.
These boxes do NAT by the Routing and Remote Access functions within Windows 2000 Server. You can read about it in this MS Knowledge Base support article . We have not setup any port mappings and do not know if the nature of this NAT (i.e. full cone, symmetric, etc?). When we find out we will update this page.
The STUN servers have the static CSUG LAN addresses and port numbers as indicated in the picture. They are configured to use each other as alternate servers.
In general, when we have any new info about the testbed we will update this page.

Steps to setup a P2P client

1. Pick one of the CSUG PCs in the room and login.
2. Run ipconfig /all and note down the DNS servers' IP addresses.
3. Now modify this machine's network settings. As you know, to modify do this you could go to Control Panel -> Network Connections -> [The Ethernet connection that you want] -> Properties; OR you could right click on My Network Places (on desktop) -> Properties -> [The Ethernet connection that you want] -> Properties. Then you would see this dialog below.

Scroll down to Internet Protocol (TCP/IP) and click properties. And you would see this dialog box.

4. Now choose a Subnet that you would like this host to be on. For Subnet 1, set the IP address of this machine to an address from 192.168.0.2 to 192.168.0.126. For Subnet 2, set it to an address from 192.168.0.130 to 192.168.0.254. Note that if the address you picked is already taken, when you press OK, Windows would tell you so.
5. Set the Subnet mask to 255.255.255.128.
6. Set the Default gateway to the IP address of the NAT boxes corresponding to your Subnet, i.e. either 192.168.0.1 or 192.168.0.129.
7. Set the DNS server addresses to the first two that appeared when you ran ipconfig /all above in step 2. These are the DNS servers on the CSUG LAN and usually don't change, so you chould usually safely put the two address shown in picture above.
8. Press OK and OK again. The machine shouldn't need to be restarted.

Note that after you restart the machine, it would be reverted to the preset CSUG PC settings.

Last update: 03/18/02. By Doug.