NetCore IPV6 socket connection fails on linux-arm - sockets

Question

I am trying to establish an IPV6 socket connection with net-core 3.0 on a linux-arm platform (raspberry pi).
At the time when I try to bind the socket to the local ethernet adapter an Exception ((22): Invalid argument [fe80::211c:bf90:fbbf:9800]:5400) is thrown.
When i try the same on my windows development machine (with a different link-local ip), everything works fine.
IPV4 socket connection is also possible on both, my windows development machine and on the target linux-arm platform.
To the source code:
I used the socket example of microsoft as a base and changed the IPV4 into an IPV6 address.
The exception is thrown after the "Bind" method.
Here is the client side code:
//definet the target endpoint
IPAddress ipAddress;
IPAddress.TryParse("fe80::211c:bf90:fbbf:9800", out ipAddress);
IPEndPoint remoteEP = new IPEndPoint(ipAddress, 5400);
// Create a TCP/IP socket.
Socket sender = new Socket(ipAddress.AddressFamily ,SocketType.Stream, ProtocolType.Tcp);
//bind to the local network interface
IPAddress localIp;
IPAddress.TryParse("fe80::833:e68b:32ee:4c39", out localIp);
EndPoint localEndPoint = new IPEndPoint(IPAddress.IPv6Any, 0);
sender.Bind(localEndPoint);
// Connect the socket to the remote endpoint. Catch any errors.
try
{
sender.Connect(remoteEP);
Console.WriteLine("Socket connected to {0}",
sender.RemoteEndPoint.ToString());

Answer 1

The input of Ron was in fact the missing part. Hence the target endpoint IpAddress has to provided with the ScopeId (NIC Nr).
//definet the target endpoint
IPAddress ipAddress;
IPAddress.TryParse("fe80::211c:bf90:fbbf:9800", out ipAddress);
ipAddress.ScopeId = scopeId;
IPEndPoint remoteEP = new IPEndPoint(ipAddress, 5400);
To the scope ID of the first link local address for example this code can be used:
private static long GetScopeIdForHostLinkLocal()
{
IPAddress firstLinkLocal = null;
var info = NetworkInterface.GetAllNetworkInterfaces();
foreach (NetworkInterface nic in info)
{
var ipProps = nic.GetIPProperties();
var uniAddresses = ipProps.UnicastAddresses;
foreach (UnicastIPAddressInformation addressInfo in uniAddresses)
{
if (addressInfo.Address.IsIPv6LinkLocal)
{
firstLinkLocal = addressInfo.Address;
break;
}
}
if (firstLinkLocal != null)
{
break;
}
}
if (firstLinkLocal != null)
{
return firstLinkLocal.ScopeId;
}
else
{
return -1;
}
}