7200emu.hacki.at

[kwiggins]

First let me say thank you to all of the people who have worked so hard to put all this information together. After taking and taking and taking, I am finally able to give something back to the community. The issue of using your wireless adapter to bridge to the real world is one that has seemed to stump quite a few people. All the while, the answer was right under our nose.

Hopefully I am not duplicating information that is already posted somewhere else. If I am, maybe this will make the info easier to find. I know I searched through the site quite a bit, and could not find the answer I needed.

Some would ask why not just use the Ethernet NIC on your PC, but if you are like me, sometimes you’d rather sit out on the deck while working on your sims instead of being chained to a desk, especially now that Spring is here and is so nice to sit outside.

The main reason I started down this path is that I wanted to run a TACACS+ server on one of my home PCs, and have my sim routers authenticate to the servers. The only way to really get to know how something works is to dive in and get as realistic as possible, and right now I’m studying TACACS+. I was successful in authenticating to my TACACS+ server using my Ethernet NIC, but as I stated earlier, I wanted to do this, and not have to sit inside, so I dived into making the wireless bridge work with GNS3.

The root of the problem is Winpcap as many people have alluded to. Winpcap states right on its website that it does not work with wireless adapters. Yet they also tell how to fix the problem. The answer to the problem is a little known feature in Windows XP of all places. All that’s needed is a bridge for the bridge, and you are on your way to communicating through you sim to the real world all the while you are soaking up some sun outside in the “real world.”

These are the steps to follow to be able to bridge your simulation to the real world using your wireless adapter.

1) Set up a Loopback adapter on your PC. There are many tutorials throughout this site that tell how to do this. Blindhog.net has an excellent video on how to setup a Loopback adapter. - http://www.blindhog.net/cisco-dynamips-with-microsoft-Loopback-interface-video-tutorial/

2) The next phase is to bridge the Loopback adapter with your wireless adapter. This is the key to making it all work.
a. Open your Network Connections
b. Use the <Ctrl> to select both the Loopback adapter you just created and your wireless adapter.
c. Right Click and the select Bridge Connections. Windows will then set up a new adapter called Network Bridge (MAC Bridge Miniport). All of the IP settings for your wireless adapter will now show up under the Network Bridge.
d. Once Windows has finished doing its thing, you are ready to connect to the real world using the wireless adapter.

3) At this point follow the instructions in the GNS3 documentation on Communicating with Real Networks. When you have the option to choose your network adapter, choose the Loopback adapter you created.
a. Be sure to give the interface on the router that connects to your cloud an IP address that is on the same subnet as your wireless network.

That's it. You should now be able to connect from your router sim to the real world using your wireless adapter.

You can also use this method to capture traffic that goes across the wireless adapter using Wireshark. To do so, just select the MAC Bridge as the interface to monitor.

For more detailed information on bridging using Windows XP, see the link below to WindowsNetworking.Com

http://www.windowsnetworking.com/articles_tutorials/wxpbrdge.html

Hopefully this will help someone "cut the cord," and use their PC the way it was intended, without wires.

[Seanlv]

Thanks a lot. I see your post from http://7200emu.hacki.at/viewtopic.php?p=21776#21776. Actully I tested this method several days ago, but without success. Today I tested again, also failed.

The problem when I bridged my wireless NIC and LOOPBACK NIC, I could not access internet and home-work resource connected via wireless card. After checking the packet in/out from my network interface, I found my wireless nic did not sent out any packets, but can receive packets from my home-work, however the received packets did not handled by Bridging NIC that I created. pls see the attachment for your reference.

[kwiggins]

Seanlv

How is the bridge configured - are you using DHCP or static for your ip address? I would recommend DHCP because it will pull an IP address through the wireless connection.

Your diagram indicated the Bridge is trying to pull information from the Loopback adapter. It shows 10M as speed where it should read as 11M (54M for wireless g) if it were functioning properly.

It is normal to see sent only packets on the Loopback interface unless you are using it to connect to the simulator. As a matter of fact, you can disable the loopback adapter and you should still be able to access your local network.

[Seanlv]

kwiggins

I configurated the bridge group as follow
1, Ctrl click the 2 NIC (wireless and loopback)
2, then choose bridge connection.

I did not configurate bridge NIC as DHCP client, beacuse it can not get a vaild IP since wireless NIC did not help bridge NIC to sent out DHCP request packets.

Yes, I agree with you. Bridge NIC did not pull information from my wireless NIC. How to say.... I think may be there is a priority list in bridge NIC's properties? And LOOPBACK NIC now have the higher priority?

I try to disable loopback NIC after creating the bridge NIC, but it's no help, the wireless NIC could not aceess my home/local network at all.


Thanks for your reply.

[Seanlv]

by the way, My wireless NIC is USB interface Netgear WG111 v2. And I tried to bridge Wire-ed NIC (Broadcom NetXtreme 57xx Gigabit Controller) with LOOPBACK NIC several days ago. It works just as your description in first post.

[daedalus01]

I know what worked for me, was cloning the physical MAC address of the wireless card to whatever router interface you've bridged to it.

so wireless NIC with MAC 01-02-03-04-05-06,

int fa0/0
mac-address 0102.0304.0506
end

then I could choose any unused IP address valid for the wireless network, and communication worked just fine.

I actually got this same thing to work bridging the router to the Cisco VPN adapter, but that one took a lot more work...

[joeh018]

In regards to the issue some are having with bridging your loopback and wireless NIC. I had the same problem bridging my wireless nic to my loopback. What was causing the issue for me was MAC security on my router. The bridge is created under a new MAC and the router would not let it associate. as soon as i plugged in the MAC of the bridge to my router the bridge came up fine.

-Joe

[rwfnetworking]

Guys,

I used the below to get my Bridge Working. Apparently with certain Wireless cards not supporting Promiscuous mode your created bridge between your Loopback Adapter and your Wireless card will no longer connect to the Internet after the Bridge is connected. The below steps will attempt to force Promiscuous mode.

1. Click Start, click Run, type cmd, and then click OK.

2. In the command window, type "netsh bridge show adapter"

3. Note the number assigned to the wireless adapter and type "netsh bridge set adapter 1 e" where you substitute the number displayed in the previous step for the number 1 in this step.

4. To double check the wireless card is correctly set with Force Compatibility Mode enabled, type the "netsh bridge show adapter" command again.


You can read about this at: (Commands in WinXP Sp3 slightly differ from this article)

http://www.microsoft.com/windowsxp/using/networking/expert/crawford_02april22.mspx


Note: The attached screen shot was my adapters after I applied the above steps. Before that the status on both "ForceCompatibilityMode" was listed as "unknown". I would appreciate hearing back from anyone that uses this as a fix to see how many this helps.



Robert