Full Version: Registry Key for Network Speed
I am the network administrator of a LAN. All of my machines' NICs are currently set to 100Mbps/Full-Duplex. I need to set all of them back to "Auto Detect". I want to connect to each machine remotely from my machine, using Registry Editor. Does anyone know the registry location for the link speed and duplex settings? Thanks! --Mark
I'm a network admin of a LAN, too! It's great fun, except when its not. 
Try this: Open Network and Dial-up Connections, right-click and go to the properties of the target NIC (also note what appears in the 'device name' field for that NIC)
- Click on 'configure' on the General Tab
- Go to the 'driver' tab
- click on 'driver details'. Note the driver file name (i.e. something.sys)
- Now, do a file search on the OS drive for .inf files, and look for one with the same name as the driver file. The idea is that you're trying to find the .inf file associated with the driver that is used to control your NIC - this file will contain a 'map' of the different registry settings controlling things like duplex and line speed and also shows where they're located in the registry for that particular driver.
- once the .inf file is found, open that file in Notepad.
- Look for the ClassGUID 'variable' in the top section of the file. This is what all of the NIC settings will be stored under in the registry.
- Now go to HKLM\System\CurrentControlSet\Control\Class\ClassGUID - where ClassGUID is the value found a few steps earlier.
- Here you'll find an index for each of the different NICs installed on your system. Go through each looking at the DriverDesc key until you find the one that matches the 'device name' field from Network and DialUp Connections. If only 1 NIC per box, it's that much easier.
- Now you've found where everything is located, the next step is figuring out what key lists the speed and duplex setting. This information will be contained within the .inf file, probably towards the bottom. You know how to read the .inf file, I'd suggest saving the registry key you're in to a text file, then making a change to the speed and duplex of the NIC, and then saving the registry key again. Then use a diff utility to discover what changed in the registry settings. Then you'll have the actual key name used and then you can do a find in the .inf file for that key name and it will lead you to a section that (hopefully) tells you what all of the possible values are and what they mean. If every workstation on your LAN has the same OS / same NIC, you're in luck - your job just became easier.
Most of the above was stolen from elsewhere, but it works - and without more info on exactly what you've got equipment-wise, it should do the trick for you.
Try this: Open Network and Dial-up Connections, right-click and go to the properties of the target NIC (also note what appears in the 'device name' field for that NIC)
- Click on 'configure' on the General Tab
- Go to the 'driver' tab
- click on 'driver details'. Note the driver file name (i.e. something.sys)
- Now, do a file search on the OS drive for .inf files, and look for one with the same name as the driver file. The idea is that you're trying to find the .inf file associated with the driver that is used to control your NIC - this file will contain a 'map' of the different registry settings controlling things like duplex and line speed and also shows where they're located in the registry for that particular driver.
- once the .inf file is found, open that file in Notepad.
- Look for the ClassGUID 'variable' in the top section of the file. This is what all of the NIC settings will be stored under in the registry.
- Now go to HKLM\System\CurrentControlSet\Control\Class\ClassGUID - where ClassGUID is the value found a few steps earlier.
- Here you'll find an index for each of the different NICs installed on your system. Go through each looking at the DriverDesc key until you find the one that matches the 'device name' field from Network and DialUp Connections. If only 1 NIC per box, it's that much easier.
- Now you've found where everything is located, the next step is figuring out what key lists the speed and duplex setting. This information will be contained within the .inf file, probably towards the bottom. You know how to read the .inf file, I'd suggest saving the registry key you're in to a text file, then making a change to the speed and duplex of the NIC, and then saving the registry key again. Then use a diff utility to discover what changed in the registry settings. Then you'll have the actual key name used and then you can do a find in the .inf file for that key name and it will lead you to a section that (hopefully) tells you what all of the possible values are and what they mean. If every workstation on your LAN has the same OS / same NIC, you're in luck - your job just became easier.
Most of the above was stolen from elsewhere, but it works - and without more info on exactly what you've got equipment-wise, it should do the trick for you.
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