[Linux] DirectoryServices.Protocols does not connect to AD-Server

[Serinoxu]

Hello dear Developers

Im made a Microservice, which should update/insert User data in the AD.

To be able to do this, I need to establish a connection. You can see my code below (it works successfully on windows, but fails on linux docker container):

private void EstablishAdConnection()
 {

     try
     {
         Console.WriteLine("Start des Verbindungsversuchs zum LDAP Server. Adresse:" + settings.Adress + " on Port:" + settings.LdapSecurePort);
         Console.WriteLine("Mit dem Benutzernamen: " + settings.FullUsername);
         var identifier = new LdapDirectoryIdentifier(settings.Adress, settings.LdapSecurePort, true, false);
         LdapConnection Ldap;
         Ldap = new LdapConnection(identifier,
             new System.Net.NetworkCredential(settings.FullUsername, settings.Password))
         {
             AuthType = AuthType.Basic
         };
         
         Ldap.SessionOptions.ProtocolVersion = 3;
         Ldap.SessionOptions.ReferralChasing = ReferralChasingOptions.None;
         Ldap.Timeout = TimeSpan.FromMinutes(0.5);
         Ldap.SessionOptions.SecureSocketLayer = true;
         Ldap.Bind();
         ProtokollAccess.GetInstance().GetServiceProtokoll().ConnectionInfo = Ldap.SessionOptions.SslInformation.AlgorithmIdentifier.ToString();
         AdRequests.SetConnection(Ldap);
     }
     catch (Exception ex)
     {
         throw;
     }

 }

csproj:

<Project Sdk="Microsoft.NET.Sdk">
	<PropertyGroup>
		<TargetFramework>net6.0</TargetFramework>
		<CopyLocalLockFileAssemblies>true</CopyLocalLockFileAssemblies>
		<Version>1.2.1</Version>
		<OutputType>Library</OutputType>
		<Nullable>enable</Nullable>
		<IsPackable>true</IsPackable>
	</PropertyGroup>

	<ItemGroup>
		<PackageReference Include="..." Version="1.14.0" />
		<PackageReference Include="MicroserviceCommonData" Version="0.0.5" />
		<PackageReference Include="System.DirectoryServices.Protocols" Version="6.0.27" />
	</ItemGroup>
</Project>

The Microservice should run in a Linux container with Ubuntu 22.04 (mcr.microsoft.com/dotnet/aspnet:6.0-jammy).
I have used 6.0.27 DirectoryService.Protocols cause it was one of a few version which are not throwing an Error that it couldn´t find the Version.

I applied many known workarounds for the linux problem.
For example:

• ReferralChasingOptions.None = Should solve the problem with Linux Container according to Why System.DirectoryServices.Protocols not working on linux? #64900

or applied the workaround from https://stackoverflow.com/questions/77109472/c-sharp-how-to-connect-to-ldap-ad-dc-server-using-ssl-or-tls-from-linux-ubuntu
which states that you should:

• use AuthType.Basic or Negotiate
• install libldap-2.5.so.0 as libldap-2.4.so.2 cause of an constant reference from the directoryService.Protocols Package to the lower version.

When my code execution hits LdapDirectoryIdentifier then the following error will be thrown:
"System.DirectoryServices.Protocols is not supported on this platfrom"

Overview:
DirectoryService.Protocols Version: 6.0.27
.Net Framework Version: net6.0
Ubuntu: 22.04

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[ericstj]

I'm not sure where you're getting DirectoryService.Protocols Version: 6.0.27 -- that doesn't exist: https://www.nuget.org/packages/System.DirectoryServices.Protocols/

When my code execution hits LdapDirectoryIdentifier then the following error will be thrown:
"System.DirectoryServices.Protocols is not supported on this platfrom"

It sounds to me like you're using the wrong binary on linux. The package contains runtime-specific implementations. It's important that your application loads the linux specific assembly. This should happen when building the application with a deps file and running normally. It may not work if you're doing something unusual with application deployment.

Double check your repro to ensure you've deployed the app correctly and are referencing an actual supported package version. If you are, then share more information from the failure - like the full callstack of the exception - the file version of the loaded binary -- and you can inspect that binary to determine what it was built for. Here's an example:

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