Develop Reference

Get name of network that a network interface is connected to

In Windows Control Panel, you can find a list of network interfaces/connections which displays the following:
In the .NET framework these are represented in the NetworkInterface class (and found via NetworkInterface.GetAllNetworkInterfaces).
For reference, say I'm reading properties from the Ethernet interface - the NetworkInterface.Name property returns "Ethernet", the NetworkInterface.Description property returns "Realtek PCIe FE Family Controller".
However, nothing in the class seems to be able to get me the name of the network it's connected to (in this case "BELL024"). How would I go about getting that string? I have to know what network the interface is associated with, not just a list of the networks that exist.

It turns out information about each network is stored as a 'network profile' by Windows, storing it's name and other info like whether it's public or not. The name can be changed by users in the control panel, but in my situation that's not a problem.
The Windows API Code Pack from Microsoft contains the APIs necessary to get the collection of network profiles. As it contains a lot of bloat that I don't need, the bare minimum code to wrap the Windows API can be found here.
A collection of the network profiles can then be found like so:
//Get the networks that are currently connected to
var networks = NetworkListManager.GetNetworks(NetworkConnectivityLevels.Connected);
Each object in the collection represents a network profile and contains a collection of NetworkConnection objects. Each NetworkConnection object appears to be info about an interface's connection to the base network.
foreach(Network network in networks)
{
//Name property corresponds to the name I originally asked about
Console.WriteLine("[" + network.Name + "]");
Console.WriteLine("\t[NetworkConnections]");
foreach(NetworkConnection conn in network.Connections)
{
//Print network interface's GUID
Console.WriteLine("\t\t" + conn.AdapterId.ToString());
}
}
The NetworkConnection.AdapterId property is the same network interface GUID that the NetworkInterface.Id property knows.
So, you can determine what network an interface is connected to, by checking if one of the network's connections have the same ID as the interface. Note that they're represented differently, so you'll have to do a bit more work:
Both my Wi-Fi and Ethernet interfaces are connected to the BELL024 network in the above example.

On Windows 8 and Windows 2012 and higher you can query WMI class MSFT_NetConnectionProfile from root/StandardCimv2 namespace.
It shouldn't be too hard to convert this to C#.
Get-WmiObject -Namespace root/StandardCimv2 -Class MSFT_NetConnectionProfile | Format-Table InterfaceAlias, Name

You can use WMI to query for your network name. You can use this code as a sample:
ManagementScope oMs = new ManagementScope();
ObjectQuery oQuery =
new ObjectQuery("Select * From Win32_NetworkAdapter");
ManagementObjectSearcher oSearcher = new ManagementObjectSearcher(oMs, oQuery);
ManagementObjectCollection oReturnCollection = oSearcher.Get();
foreach (ManagementObject oReturn in oReturnCollection)
{
if (oReturn.Properties["NetConnectionID"].Value != null)
{
Console.WriteLine("Name : " + oReturn.Properties["NetConnectionID"].Value);
}
}

How do I uniquely identify only network connections that are *not* VPN connections?

I'm trying to track all current network connections at run time, but I want to exclude VPN connections.
I need to be able to identify the network(s) being connected to, as well, so I'm using NetworkListManagerClass() to build a list of current connections:
var manager = new NetworkListManagerClass();
var connectedNetworks = manager.GetNetworks(NLM_ENUM_NETWORK.NLM_ENUM_NETWORK_CONNECTED).Cast<INetwork>();
I believe I can determine if a connection adapter is for a VPN by examining the NetworkInterfaceType of the NetworkInterface class:
NetworkInterface[] interfaces = NetworkInterface.GetAllNetworkInterfaces().Where(n => n.OperationalStatus == OperationalStatus.Up).ToArray();
foreach (NetworkInterface n in interfaces)
{
if (n.NetworkInterfaceType == NetworkInterfaceType.Tunnel || n.NetworkInterfaceType == NetworkInterfaceType.PPP)
{
}
}
However, it isn't enough for me to just know that an interface is or is not a VPN. I need to be able to track details about the network that the non-VPN interfaces are connected to.
For example:
We'll call my work network "officenetwork". We'll call my home network "homenetwork".
If I'm at work, I can see I'm connected to officenetwork by examining NetworkListManagerClass based off the NLM_ENUM_NETWORK_CONNECTED status. My application should know that officenetwork is my current local network, and will store and reference settings specific to that network.
Similarly, if I'm at home, I should be able to see homenetwork, and store and reference a different set of settings specific to that network.
However, if I'm at home, and I use a VPN to connect to officenetwork, examining NetworkListManagerClass based off the NLM_ENUM_NETWORK_CONNECTED status will show both homenetwork and officenetwork. Since the connection to officenetwork is a VPN, I need to ignore it, and only store and reference the settings for homenetwork.
This software will be for users who will connect to networks I know nothing about, so I cannot assume connection data for specific VPN's or networks.
How can I check current network connections and identify only networks that are not VPN connections, so I can store custom settings for that network?

From an INetwork instance, you can get the list of connections (INetworkConnections instances) using the GetNetworkConnections method.
Then, using the INetworkConnection::GetAdapterId method, you can get a Guid that represent the adapter Id. The adapter Id in fact matches the NetworkInterface.Id Property (it's a string, but you can convert it to a Guid).
Here is a sample console app that dumps all network and their connections, and interface properties (type, name, etc.):
class Program
{
static void Main(string[] args)
{
var mgr = new NetworkListManager();
foreach (INetwork network in mgr.GetNetworks(NLM_ENUM_NETWORK.NLM_ENUM_NETWORK_ALL))
{
Console.WriteLine("Network: " + network.GetName());
foreach (INetworkConnection conn in network.GetNetworkConnections())
{
Console.WriteLine(" Adapter Id: " + conn.GetAdapterId());
var ni = NetworkInterface.GetAllNetworkInterfaces().FirstOrDefault(i => new Guid(i.Id) == conn.GetAdapterId());
Console.WriteLine(" Interface: " + ni.Name);
Console.WriteLine(" Type: " + ni.NetworkInterfaceType);
}
}
}
}

Is there really any way to uniquely identify any computer at all

I know there are a number of similar questions in stackoverflow such as the followings:
What's a good way to uniquely identify a computer?
What is a good unique PC identifier?
Unique computer id C#
WIN32_Processor::Is ProcessorId Unique for all computers
How to uniquely identify computer using C#?
... and dozens more and I have studied them all.
The problem is that some of the accepted answers have suggested MAC address as an unique identifier which is entirely incorrect. Some other answers have suggested to use a combination of various components which seems more logical. However, in case of using a combination it should be considered which component is naturally unlikely to be changed frequently. A few days ago we developed a key generator for a software licensing issue where we used the combination of CPUID and MAC to identify a windows pc uniquely and till practical testing we thought our approach was good enough. Ironically when we went testing it we found three computers returning the same id with our key generator!
So, is there really any way to uniquely identify any computer at all? Right now we just need to make our key generator to work on windows pc. Some way (if possible at all) using c# would be great as our system is developed on .net.
Update:
Sorry for creating some confusions and an apparently false alarm. We found out some incorrectness in our method of retrieving HW info. Primarily I thought of deleting this question as now my own confusion has gone and I do believe that a combination of two or more components is good enough to identify a computer. However, then I decided to keep it because I think I should clarify what was causing the problem as the same thing might hurt some other guy in future.
This is what we were doing (excluding other codes):
We were using a getManagementInfo function to retrieve MAC and Processor ID
private String getManagementInfo(String StrKey_String, String strIndex)
{
String strHwInfo = null;
try
{
ManagementObjectSearcher searcher = new ManagementObjectSearcher("select * from " + StrKey_String);
foreach (ManagementObject share in searcher.Get())
{
strHwInfo += share[strIndex];
}
}
catch (Exception ex)
{
// show some error message
}
return strHwInfo;
}
Then where needed we used that function to retrieve MAC Address
string strMAC = getManagementInfo("Win32_NetworkAdapterConfiguration", "MacAddress");
and to retrieve ProcessorID
string strProcessorId = getManagementInfo("Win32_Processor", "ProcessorId");
At this point, strMAC would contain more than one MAC address if there are more than one. To take only one we just took the first 17 characters (12 MAC digits and 5 colons in between).
strMAC = strMAC.Length > 17 ? strMAC.Remove(17) : strMAC;
This is where we made the mistake. Because getManagementInfo("Win32_NetworkAdapterConfiguration", "MacAddress") was returning a number of extra MAC addresses that were really in use. For example, when we searched for MAC addresses in the command prompt by getmac command then it showed one or two MAC addresses for each pc which were all different. But getManagementInfo("Win32_NetworkAdapterConfiguration", "MacAddress") returned four to five MAC addresses some of which were identical for all computers. As we just took the first MAC address that our function returned instead of checking anything else, the identical MAC addresses were taken in strMAC incidently.
The following code by Sowkot Osman does the trick by returning only the first active/ enabled MAC address:
private static string macId()
{
return identifier("Win32_NetworkAdapterConfiguration", "MACAddress", "IPEnabled");
}
private static string identifier(string wmiClass, string wmiProperty, string wmiMustBeTrue)
{
string result = "";
System.Management.ManagementClass mc = new System.Management.ManagementClass(wmiClass);
System.Management.ManagementObjectCollection moc = mc.GetInstances();
foreach (System.Management.ManagementObject mo in moc)
{
if (mo[wmiMustBeTrue].ToString() == "True")
{
//Only get the first one
if (result == "")
{
try
{
result = mo[wmiProperty].ToString();
break;
}
catch
{
}
}
}
}
return result;
}
//Return a hardware identifier
private static string identifier(string wmiClass, string wmiProperty)
{
string result = "";
System.Management.ManagementClass mc = new System.Management.ManagementClass(wmiClass);
System.Management.ManagementObjectCollection moc = mc.GetInstances();
foreach (System.Management.ManagementObject mo in moc)
{
//Only get the first one
if (result == "")
{
try
{
result = mo[wmiProperty].ToString();
break;
}
catch
{
}
}
}
return result;
}
However, I was absolutely right about the identical Processor ID issue. All three returned the same Processor ID when we put wmic cpu get ProcessorId command in their command prompts.
Now we have decided to use Motherboard serial number instead of Processor ID to make a combination with MAC address. I think our purpose will be served with this way and if it doesn't in some cases then we should let it go in those few cases.

How about adding motherboard serial number as well e.g.:
using System.management;
//Code for retrieving motherboard's serial number
ManagementObjectSearcher MOS = new ManagementObjectSearcher("Select * From Win32_BaseBoard");
foreach (ManagementObject getserial in MOS.Get())
{
textBox1.Text = getserial["SerialNumber"].ToString();
}
//Code for retrieving Processor's Identity
MOS = new ManagementObjectSearcher("Select * From Win32_processor");
foreach (ManagementObject getPID in MOS.Get())
{
textBox2.Text = getPID["ProcessorID"].ToString();
}
//Code for retrieving Network Adapter Configuration
MOS = new ManagementObjectSearcher("Select * From Win32_NetworkAdapterConfiguration");
foreach (ManagementObject mac in MOS.Get())
{
textBox3.Text = mac["MACAddress"].ToString();
}

The fact in getting a globally unique ID is, only MAC address is the ID that will not change if you set up your system all over. IF you are generating a key for a specific product, the best way to do it is assigning unique IDs for products and combining the product ID with MAC address. Hope it helps.

I Completely agree with just the above comment.
For Software licensening, you can use:
Computer MAC Address (Take all if multiple NIC Card) + Your software Product Code
Most of the renowned telecom vendor is using this technique.

However, I was absolutely right about the identical Processor ID
issue. All three returned the same Processor ID when we put wmic cpu
get ProcessorId command in their command prompts.
Processor ID will be same if all the systems are running as virtual machines on the same hypervisor.
MAC ID seems fine. Only thing is users must be provided the option to reset the application, in case the MAC changes.

It looks like custom kitchen is the way for that.
SMBIOS UUID (motherboard serial) is not robust, but works fine in 99% cases. However some brands will set the same UUID for multiple computers (same production batch maybe). Getting it requires WMI access for the user (if he's not administrator), you can solve that by starting an external process asking administrator priviledges (check codeproject.com/Articles/15848/WMI-Namespace-Security)
Windows Product ID might be good, but I read it could be identical in some circumstances (https://www.nextofwindows.com/the-best-way-to-uniquely-identify-a-windows-machine)
Could someone clarify if the same Product ID (not product key) might be present on multiple computers ?
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\MachineGuid seems interesting. It's generated when installing Windows and if changed, it requires to reactivate Windows.
Mac Addresses are interresting but you can only take the first one or your unique ID will change when the interface is disabled, or when another network interface is added and appears first etc.
Hard Drive serial number is nice but when installing a ghost, it might also override the serial number from the original drive... And the HD serial is very easy to change.
The best might be to generate an ID with a combination of those machine identifiers and decide if the machine is the same by comparing those identifiers (ie if at least one Mac address + either SMBIOS UUID or Product ID is ok, accept)

NetAddresses always null in Win32_NetworkAdapter query

I am trying to get the active network adapter's IP address, so that I avoid virtual and other VPN adapters that are not connected at present.
On my current laptop the following code returns 3 IP V4 addresses, and I don't know how to get the "real", in use IP address from that list.
IPAddress[] ipV4Addresses = Array.FindAll(
Dns.GetHostEntry(String.Empty).AddressList,
a => a.AddressFamily == AddressFamily.InterNetwork);
Looking at MSDN doc here, I thought maybe I was on the right track. Has anyone obtained the list of IP addresses per adapter successfully? If so, please share your wisdom. Thanks!
This is all prototype at this point. I have this code (thanks to SO!), and the string[] netAddresses is always null, even with the computer connected to a network and with a functioning IP address.
string wmiQuery = "SELECT * FROM Win32_NetworkAdapter WHERE NetConnectionId != NULL";
ManagementObjectSearcher moSearch = new ManagementObjectSearcher(wmiQuery);
ManagementObjectCollection moCollection = moSearch.Get();
foreach (ManagementObject mo in moCollection)
{
Console.WriteLine("{0} is {1}", mo["Name"], mo["NetConnectionStatus"]);
string[] netAddresses = (string[])mo["NetworkAddresses"];
if (netAddresses != null)
{
foreach (string netAddress in netAddresses)
{
Console.WriteLine("\tnet addresses:");
Console.WriteLine("\t\t{0}", netAddress);
}
}
}

from MS docs: http://msdn.microsoft.com/en-us/library/windows/desktop/aa394216%28v=vs.85%29.aspx
NetworkAddresses
Data type: string array
Access type: Read-only
Array of network addresses for an adapter. This property is inherited from CIM_NetworkAdapter.
This property has not been implemented yet. It returns a NULL value by default.

There's no such thing as a "real" IP address. Each packet you send is routed to its destination based on the metric of the adapter and the available routing paths. You can guess which IP is primarily being used for internet traffic by doing the following:
Order your adapters by metric, lowest first.
Prioritise WAN IPs, then 192.168.x.x, then 10.x.x.x, and totally ignore loopback addresses.
This will give you a guess as to the "preferred" address, though it's hardly definitive.

Look at WIn32_NetworkAdapterConfiguration, by using the InterfaceIndex from Win32_NetworkAdapter you should be able to get the configuration you need with the ipaddresses assigned to that nic.

How do i set the dns search suffix for a network adapter in .net?

I've written a command line utility that detects which network interface is connected, and sets the staitc ip address and dns servers for it (by calling netsh). However, I can't seem to figure out how to set the dns search suffixes. netsh doesnt appear capable of doing that. How do I do that otherwise (WMI perhaps)?

I think you have to set the value(s) you want in the DNSDomainSuffixSearchOrder property of the Win32_NetworkAdapterConfiguration WMI object.
Here's and example of setting values in WMI, if you need it:
Modifying Objects & Running Methods

The dns search suffixes are valid for the whole machine, not for a single network adapter. You can also get them from registry:
string searchList = "";
try
{
using (var reg = Microsoft.Win32.Registry.LocalMachine.OpenSubKey(tcpSettingsSubKey))
{
searchList = (reg.GetValue("SearchList") as string);
}
}
catch(Exception ex)
{
// something went wrong
}
(This is not the default dns suffix when the machine is an AD member)