No Internet Connection after uninstalling Network Bridge

Delete the bridge, reboot to the Windows Safe mode (F8 while Windows starts), delete and uninstall any bridge entries, the TCP/IP protocol, your NIC entry, then reboot and let it be found again.  Avoid letting a bridge be installed - do not use the Windows Network Wizard.

Thanks John. I deleted and uninstalled the bridge and the NIC......still not working.

I couldn't uninstall the TCP/IP protocol. As far as I know, in XP that is not possible, is it?

Xavier. 

I've only experience with 2000, not XP.  I go to the NIC properties, hilight the TCP/IP protocol in the box of loaded options, delete it, then reboot and add a protocol (obviously TCP/IP) back in.  XP?; dunno.

With XP, TCP can be reset, but not uninstalled.  This Microsoft article explains how to do that.

The essential step is this. In a cmd.exe window (Start/Run cmd.exe), enter this:

netsh int ip reset c:\resetlog.txt

The log file containing the results will be c:\resetlog.txt.

Jim

Thanks johnallg and jimw!

 

I inadvertently installed a bridge on my new Iinspiron 9100 and your posts were essential to resetting my network connections.  You guys keep these boards running!

 

Regards,

ReedZ

 

Inspiron 9100 P4 3.2 WUXGA

Message Edited by ReedZ on 04-27-2004 09:44 AM

Thanks Jim.

It didn't work. Here is what I did: In safe mode, I uninstalled the Bridge and the NIC. Then I restarted and the NIC was recognized and automatically its driver was installed. Then I ran netsh int ip reset c:\resetlog.txt.

I've been trying to use a network in which the IP address is obtained automatically, and as I said in my original message, the problem is that I have internet access as long as I have a bridge installed. However, if I plug my computer in a different network in which I can specify an IP address, it works without the bridge. Any idea?

Xavier.

Can you post the output from ipconfig /all? The way to do that is to open a cmd.exe window (Start/Run cmd.exe), and in the window that opens, type ipconfig /all > c:\ipconfig.txt. Then open the file c:\ipconfig.txt with Notepad, select all (Ctrl-A), copy it (Ctrl-C), and paste it (Ctrl-V) into a reply.

Maybe if we see what XP created in the way of network interfaces, we can figure out which ones are needed to make things work.

Jim

Message Edited by jimw on 04-27-2004 09:59 PM

Here is the output from ipconfig /all:

Windows IP Configuration

 

        Host Name . . . . . . . . . . . . : Inspiron

        Primary Dns Suffix  . . . . . . . :

        Node Type . . . . . . . . . . . . : Hybrid

        IP Routing Enabled. . . . . . . . : No

        WINS Proxy Enabled. . . . . . . . : No

 

Ethernet adapter Local Area Connection 8:

 

        Connection-specific DNS Suffix  . : gradstudents.utoronto.ca

        Description . . . . . . . . . . . : 3Com 3C920 Integrated Fast Ethernet Controller (3C905C-TX Compatible)

        Physical Address. . . . . . . . . : 00-08-74-E9-02-31

        Dhcp Enabled. . . . . . . . . . . : Yes

        Autoconfiguration Enabled . . . . : Yes

        IP Address. . . . . . . . . . . . : 142.151.170.131

        Subnet Mask . . . . . . . . . . . : 255.255.254.0

        Default Gateway . . . . . . . . . : 142.151.170.1

        DHCP Server . . . . . . . . . . . : 128.100.100.129

        DNS Servers . . . . . . . . . . . : 128.100.100.128

                                            128.100.102.201

        Lease Obtained. . . . . . . . . . : April 28, 2004 10:39:00 PM

        Lease Expires . . . . . . . . . . : April 29, 2004 10:39:00 PM

 

Thanks,

Xavier.

Hmmm...no sign of the bridge! If it were there, I'd have expected to see an entry like this:

Ethernet adapter Network Bridge (Network Bridge)

but there isn't one!

While I can "tracert" to your gateway (142.151.170.1), I can't "tracert" to the IP address listed (142.151.170.131) for your connection. That's likely reasonable - UToronto probably has it firewalled. But other than that last hop, everything looks OK.

Is the ipconfig output you posted from a working or non-working setup? If that's the working setup, where's the bridge? Very odd! It looks like it should work!

What happens if you try tracert 209.123.109.175 from the non-working setup? That's the IP address of dslreports.com. If you can't "tracert" to it, can you "ping" it ( ping 209.123.109.175)?

If that doesn't work, can you "tracert" to 38.112.2.34? That's UToronto's connection to their ISP, cogentco.com.

(Note that the "ping"s and "tracert"s should be done in an open cmd.exe window.)

Jim

Hi Jim,

Sorry, the ipconfig output I posted was from the non-working setup. Here is the one from the working setup (you can see the bridge there):

Windows IP Configuration

 

        Host Name . . . . . . . . . . . . : Inspiron

        Primary Dns Suffix  . . . . . . . :

        Node Type . . . . . . . . . . . . : Hybrid

        IP Routing Enabled. . . . . . . . : No

        WINS Proxy Enabled. . . . . . . . : No

 

Ethernet adapter Network Bridge (Network Bridge):

 

        Connection-specific DNS Suffix  . : gradstudents.utoronto.ca

        Description . . . . . . . . . . . : MAC Bridge Miniport

        Physical Address. . . . . . . . . : 02-08-74-E9-02-31

        Dhcp Enabled. . . . . . . . . . . : Yes

        Autoconfiguration Enabled . . . . : Yes

        IP Address. . . . . . . . . . . . : 142.151.171.90

        Subnet Mask . . . . . . . . . . . : 255.255.254.0

        Default Gateway . . . . . . . . . : 142.151.170.1

        DHCP Server . . . . . . . . . . . : 128.100.100.129

        DNS Servers . . . . . . . . . . . : 128.100.100.128

                                            128.100.102.201

        Lease Obtained. . . . . . . . . . : April 30, 2004 12:15:29 AM

        Lease Expires . . . . . . . . . . : May 1, 2004 12:15:29 AM

 

I couldn't tracert to 209.123.109.175 or 38.112.2.34 from the non-working setup. I also tried to ping them, but I couldn't.

Xavier.

 

XT,

I'm stumped! The two sets of "ipconfig" output are similar in all respects except for what the listed interface is.

The two interfaces are clearly related:

Description . . . . . . . . . . . : MAC Bridge Miniport
Physical Address. . . . . . . . . : 02-08-74-E9-02-31

Description . . . . . . . . . . . : 3Com 3C920 Integrated Fast Ethernet Controller (3C905C-TX Compatible)
Physical Address. . . . . . . . . : 00-08-74-E9-02-31

They differ by exactly one binary digit.

Interestingly, the MAC address range "00-08-74" is registered to Dell. I haven't been able to locate the registration for "02-08-74".

(edit) OK, I found this: "A MAC address that starts with 02, meaning the second bit being a 1, is a LAA, a Locally Assigned Address. Someone (or some application program or operating system) has deliberately changed the MAC address of the ethernet interface, from the UAA Universally Assigned Address (globally unique) burned-in address to a self-defined mac address." So the MAC address of the bridge is locally assigned, based on the underlying 3C920's MAC address.

Different IP addresses were obtained from the DHCP server, but they're on the same network.

The only time a network bridge is needed in XP is when there are two physical interfaces that might be able to transport TCP/IP traffic between different kinds of network media, such as Bluetooth and Ethernet, or wireless and Ethernet. If a machine has only one physical interface, no bridge should be created or needed.

This article from the US University of Pennsylvania discusses the problem, and references a Microsoft Knowledge Base article about the problems associated with XP bridges. I wonder whether the UToronto Help Desk folks can give you a hand. They may be aware of problems that aren't evident outside the campus network.

(edit #2) The bottom line about XP bridges is that there have to be two physical devices capable of carrying TCP/IP traffic before a bridge will be installed by XP! See this "How-To" from HomeNetHelp.com about setting up a bridge. What's not known is what the other device besides the 3C920 is. It takes two to make a bridge.

The only additional output I can think of that might shed more light on the problem is the machine's routing table. That can be obtained by posting the output of the netstat -r. Since the non-working "netstat" output looks like it should work, can you post the output from both the working (bridge) and non-working configurations?

Jim

Message Edited by jimw on 04-30-2004 09:57 AM

Message Edited by jimw on 04-30-2004 10:42 AM

Hi Jim,

I have a 1394 device, and therefore the bridge is created between this device and the 3C920, even though the 1394 device is disabled. I tried to fix the connection doing what is suggested in the MS Knowledge Base article referenced by the University of Pennsylvania, in order to prevent the Network Setup Wizard from creating a bridge, but I lost my connection again.

Anyway, here is the output from the netstat -r:

WORKING CONFIGURATION:

===========================================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x10003 ...02 08 74 e9 02 31 ...... MAC Bridge Miniport
===========================================================================
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0    142.151.170.1  142.151.171.90   20
        127.0.0.0        255.0.0.0        127.0.0.1       127.0.0.1   1
    142.151.170.0    255.255.254.0   142.151.171.90  142.151.171.90   20
   142.151.171.90  255.255.255.255        127.0.0.1       127.0.0.1   20
  142.151.255.255  255.255.255.255   142.151.171.90  142.151.171.90   20
        224.0.0.0        240.0.0.0   142.151.171.90  142.151.171.90   20
  255.255.255.255  255.255.255.255   142.151.171.90  142.151.171.90   1
Default Gateway:     142.151.170.1
===========================================================================
Persistent Routes:
  None

Route Table

 

NON-WORKING CONFIGURATION:

===========================================================================
Interface List
0x1 ........................... MS TCP Loopback interface
0x10004 ...00 08 74 e9 02 31 ...... 3Com 3C920 Integrated Fast Ethernet Controller (3C905C-TX Compatible)
===========================================================================
===========================================================================
Active Routes:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0    142.151.170.1  142.151.170.131   20
        127.0.0.0        255.0.0.0        127.0.0.1       127.0.0.1   1
    142.151.170.0    255.255.254.0  142.151.170.131  142.151.170.131   20
  142.151.170.131  255.255.255.255        127.0.0.1       127.0.0.1   20
  142.151.255.255  255.255.255.255  142.151.170.131  142.151.170.131   20
        224.0.0.0        240.0.0.0  142.151.170.131  142.151.170.131   20
  255.255.255.255  255.255.255.255  142.151.170.131  142.151.170.131   1
Default Gateway:     142.151.170.1
===========================================================================
Persistent Routes:
  None

Route Table

Thanks,

Xavier.

I have a 1394 device, and therefore the bridge is created between this device and the 3C920, even though the 1394 device is disabled.

OK, that explains XP's interest in the bridge. Bluetooth is capable of handling TCP/IP traffic.

I'm beginning to wonder if it's time to call the U of T help desk. Note that the bridge always receives the same IP address (142.151.171.90/subnet mask 255.255.254.0), and the 3C920 always receives a different one (142.151.170.131/subnet mask 255.255.254.0). Both those are valid for the listed gateway, 142.151.170.1. Can you ping the gateway (142.151.170.1) from the non-working configuration?

I wonder if the University has some sort of "network registration" system based on MAC addresses, and that system latched on to the "bridge" MAC address (02:08:74:e9:02:31) and is disallowing traffic from the 3C920's MAC address, 00:08:74:e9:02:31, because it's not properly registered.

Both routing tables look fine, as does almost everything else I've seen. It's time to look for an external cause for this behavior.

Jim

Jim,

I don't know what happened, but I just deleted the bridge, just the same way I had been doing it for two weeks, in order to see if I could ping the gateway, and I realized that my internet connection was working. This is really strange. Thank you for all your help.

Xavier.

Glad it's working! That's the setup that should have worked all along! Makes you wonder if the U of T network help desk folks read the Dell Forums!

Jim

Message Edited by jimw on 05-03-2004 09:58 PM