ASP.NET Core 2.0 LDAP Active Directory Authentication

Question

I have found a lot of information from the past saying that LDAP authentication isn\'t enabled yet but you can get around that using third party packages. However, it seems

Answer 1

According to #2089, it is only available in Windows Compatibility-Pack for .NET Core. I currently use Novell.Directory.Ldap.NETStandard.

public bool ValidateUser(string domainName, string username, string password)
{
   string userDn = $"{username}@{domainName}";
   try
   {
      using (var connection = new LdapConnection {SecureSocketLayer = false})
      {
         connection.Connect(domainName, LdapConnection.DEFAULT_PORT);
         connection.Bind(userDn, password);
         if (connection.Bound)
            return true;
      }
   }
   catch (LdapException ex)
   {
      // Log exception
   }
   return false;
}

For authentication and authorization, we can use Cookie Authentication Middleware with claims.

public void Configure(IApplicationBuilder app, IHostingEnvironment env, 
   ILoggerFactory loggerFactory)
{
   app.UseCookieAuthentication(new CookieAuthenticationOptions
   {                
      AuthenticationScheme = "AuthenticationScheme",
      LoginPath = new PathString("/Account/Login"),
      AccessDeniedPath = new PathString("/Common/AccessDenied"),
      AutomaticAuthenticate = true,
      AutomaticChallenge = true
   });
}

It has few moving pieces, so I created a working sample project at GitHub. There are two main pieces - LdapAuthenticationService and SignInManager.