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Unix domain socket: A socket operation encountered a dead network

I'm using Unix Domain Socket for the first time,
I have created the following console application using .NET 5.0 to learn about Unix Domain Sockets.
I found the code here (https://medium.com/codex/unix-domain-sockets-in-net-6-basics-and-real-world-examples-8982898ab293)
My expectation is that similar to TCP/IP socket connection, i will be able to talk between the client and server but using Unix Domain sockets instead.
Following is the code:
class Program
{
static void Main(string[] args)
{
const string Hostname = "localhost";
const string UnixSocketPath = "/tmp/foo.sock";
using var socket = new Socket(AddressFamily.Unix, SocketType.Stream, ProtocolType.IP);
var endpoint = new UnixDomainSocketEndPoint(UnixSocketPath);
socket.Connect(endpoint);
var requestBytes = System.Text.Encoding.UTF8.GetBytes($"GET / HTTP/1.0\r\nHost: {Hostname}\r\nAccept: */*\r\n\r\n");
socket.Send(requestBytes);
byte[] receivedBytes = new byte[1024];
socket.Receive(receivedBytes, 1024, SocketFlags.None);
Console.WriteLine(System.Text.Encoding.UTF8.GetString(receivedBytes));
}
}
I get the following error when i try to run my application:
"A socket operation encountered a dead network" at socket.Connect(endpoint) line.
I have the following questions:
Is it expected for the above console application to run in a windows system?
After reading couple of articles i understand that the "UnixSocketPath" is the file based path which is followed in a Unix machine. What does it refer to in case of a Windows machine? Or is it just a temporary file created in the output directory of the application.
I tried the following to resolve the error "A socket operation encountered a dead network" after reading up a bit on this:
Try to run the application in admin mode - does not work, same error
Switch to .net core 3.0 (even though i was not facing any compile time errors with .net 5.0)
does not work, same error.
Tried to change the "UnixSocketPath" to a local path (Eg: C:/Test/foo.sock ) - does not work, error : "No connection could be made because the target machine actively refused it. C:/Test/foo.sock"
Excuse me for these noob level questions, the entire socket level programming is new to me and i'm quite confused now .
Any suggestions are appreciated. Thanks

From your posted link:
To run the example on Windows-based systems, I can recommend WSL 2. Visual Studio and Visual Studio Code come with excellent remote integrations so you can run the code directly from the development environment.
WSL is "Windows subsystems for linux", i.e. a linux virtual machine that has some integrations with the windows host.
So you would need to run your program in this WSL environment, and have this configured correctly. See Debug .NET Apps in WSL with Visual Studio
However, if you just want your server and client to talk to each other I would consider if this really is the right approach. While unix domain sockets might have some performance advantages, you require both applications to be run on the same computer. I would just use some message based protocol and instead try to minimize the number and size of messages.

С# WSAEINVAL (10022) Invalid argument on socket create

I'm trying to create a chat on C# with WinSock (System.Net.Sockets) for the institute. On my computer everything works fine. On the ones in the institute it throws an exception on the line:
socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
SocketException: WSAEINVAL (10022) Invalid argument on socket create.
All arguments are absolutely following the guidelines.
I managed to find this thread (seems like my kind of problem).
Microsoft even created a patch to this one.
Institute computer runs on Windows7. I got no administator rights neither I am allowed to show chat on my notebook. So, it seems that I cannot edit windows registry or install an update. Are there any ways for me to fix or avoid this problem?

'No connection could be made because the target machine actively refused it'

I am working on a 'Smart Device Project' using .Net Framework 3.5. I am trying to connect to some Java SOAP services on a remote server.
In order to do that, I added 'Web References' to my project.
When I try to call my web service I get a WebException 'Unable to connect to the remote server' with the inner exception being 'No connection could be made because the target machine actively refused it'.
I searched quite a lot on the Web and StackOverflow and found a lot of ASP configuration and 'Unavaliable port' answers, but as I have another application using the exact same Service successfully, I can't get why the new one isn't getting through (It did sometimes through my tests so I suppose my client implementation isn't that bad)
I tried to look if there was some connection issue on the port by using some TcpClient:
System.Net.Sockets.TcpClient client = new System.Net.Sockets.TcpClient();
try
{
client.Connect("myServerName", 8087);
MessageBox.Show("Success");
} catch (Exception ex)
{
MessageBox.Show("Failure");
}
finally
{
client.Close();
}
This connection succeed.
Here is a sample on how I call my WebService:
WSServiceExtended srv = new WSServiceExtended();
srv.Proxy = new System.Net.WebProxy();
ServeurWSI wsi = new ServeurWSI();
srv.Url = "http://myServerName:8087/myServerApp/services/myService";
wsr = srv.login(wsi);
The service is called 'Extended' because I overrided the auto-generated one in order to add Cookie managment since I am using the Compact Framework. Following the sample in this thread:
https://social.msdn.microsoft.com/Forums/en-US/34d88228-0b68-4fda-a8cd-58efe6b47958/no-cookies-sessionstate-in-compact-framework?forum=vssmartdevicesvbcs
EDIT:
I made some new tests with the Web references and got it to work.
When I add the Web Reference, I have to put some Url to the Web Service. When I set it with the actual hostname instead of the 'localhost' everything is fine.
But then, since I set it manually to the real address just before the call, it shouldn't matter
srv.Url = "http://myServerName:8087/myServerApp/services/myService";
EDIT2:
I might have forgotten some specifics about my environnement.
The Web Services are exposed on my computer on some Tomcat Server.
The application I am working on is also developped on this computer (That's why I can add Web References by putting 'localhost' in the address)
The application is then deployed on a distant device (Windows CE) that will make calls the Web Services through WIFI (There, localhost wouldn't work then)
I tried calling the Web services from other computers successfully.
I'm beginning to think that there might be some differential between the called Url and the one that is set, otherwise, how would I have a difference in behaviour such as the one described in the first edit?
EDIT3:
Well..Seems like it's not a network issue but a .Net compact framework (usage?) issue...
The Url property of the Web Service implementation is simply ignored and the one in the Reference.cs is used in place.
If someone had some idea on how I could troubleshot this, I would really appreciate it.

That error means that you reached a server and the server said "no way". So you're either hitting the wrong server or the wrong port.
I find the telnet client is useful for testing stuff like this. From the command line, you can do:
telnet [servername] [port]
So something like:
telnet myServerName 8087
If it goes to a blank screen, then it connected successfully. If it does not connect, it'll tell you.
The telnet client is no longer installed by default in Windows 7+, so you'll have to install it. See here for instructions: https://technet.microsoft.com/en-ca/library/cc771275
If the connection does open, you could paste in an actual HTTP request to see what happens. A simple GET would look something like this:
GET /myServerApp/services/myService HTTP/1.1
Host: myServerName:8087

One reason for this error can be that the service binds to only a certain IP address. It could well be that the service only listens on the IP that is assigned to the host name, but not on the localhost IP (127.0.0.1).
For example:
If the host myServerName has the public IP 192.168.0.1, your service can choose to listen on all IPs assigned to the host (sometimes specifying 0.0.0.0), or it can specifically listen on 192.168.0.1 only. In that case you will not be able to connect through 127.0.0.1, because the service simply doesn't listen on that IP.
You can "use" this inverse of this feature to make a service accessible only to local clients, not on the public IP-Address, by listening on 127.0.0.1 only, but not on the public IP. This is sometimes used on Linux for example to make MySQL only accessible on the host itself.

I was starting to forget this post but I finally found the problem that was messing things up and it has nothing to do with programmation.
I was doing the calls while the device was connected to the computer via the 'Windows Mobile Device Center' allowing to access the device from Windows.
While connected, the host provided is ignored and all calls on the specified port are handled by the connected computer.
Disconnecting the device allows to communicate properly...

What is diffrence between win form application and class library app when using SSL connection

I have a Class library application in which I'm trying to use SSL connection.
but when i tried to get Authenticate As a Client to server i got the following error message:
ssl.AuthenticateAsClient("TargetHost");
"Unable to find an entry point named 'EnumerateSecurityPackagesW' in DLL 'security.dll'."
i have done this scenario in windows application and it works fine.
have any body experience about this?
SslStream ssl = null;
TcpClient client = new TcpClient();
client.Connect("127.0.0.1", 9988);
NetworkStream _NetworkStream = client.GetStream();
IPAddress ipAdd = IPAddress.Parse("127.0.0.1");
IPEndPoint remoteEP = new IPEndPoint(ipAdd, 9988);
ssl = new SslStream(_NetworkStream,
false,new RemoteCertificateValidationCallback(CertificateValidationCallback));
ssl.AuthenticateAsClient("TargetHost");

Could you check that the security.dll library file is available to the application using your class library?
Your first app seems to require this native library. Check if it's included along the application executable.
The second app references your custom class library, which apparently cannot load the security.dll native dll
"Unable to find an entry point named 'EnumerateSecurityPackagesW' in DLL 'security.dll'."
You should compare the directory containing the two apps, and maybe include in the second app the absent dll.

TCP Socket.Connect is generating false positives

I'm experiencing really weird behavior with the Socket.Connect method in C#. I am attempting a TCP Socket.Connect to a valid IP but closed port and the method is continuing as if I have successfully connected. When I packet sniffed what was going on I saw that the app was receiving RST packets from the remote machine. Yet from the tracing that is in place it is clear that the connect method is not throwing an exception. Any ideas what might be causing this?
The code that is running is basically this
IPEndPoint iep =
new IPEndPoint(System.Net.IPAddress.Parse(m_ipAddress), m_port);
Socket tcpSocket = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
tcpSocket.Connect(iep);
To add to the mystery... when running this code in a stand alone console application, the result is as expected – the connect method throws an exception. However, when running it in the Windows Service deployment we have the connect method does not throw an exception.
Edit in response to Mystere Man's answer
How would the exception be swallowed? I have a Trace.WriteLine right above the .Connect method and a Trace.WriteLine right under it (not shown in the code sample for readability). I know that both traces are running. I also have a try catch around the whole thing which also does a Trace.Writeline and I don't see that in the log files anywhere. I have also enabled the internal socket tracing as you suggested. I don't see any exceptions. I see what appears to be successful connections.
I am trying to identify differences between the windows service app and the diagnostic console app I made. I am running out of ideas though
End edit
Thanks

Are you sure the exception isn't being caught and swallowed in the service, but not in the console app?
My first step would be to isolate the differences between the two implementations. You mention tracing, but you don't say whether this is Network tracing (part of the BCL) or your own tracing. If you're not using network tracing, then enable that.

see AppDomain.CurrentDomain.UnhandledException

I have never observed this again. It seems to me that something was corrupt somewhere. Either the OS on which the app was installed or the .NET framework.