authenticate user in LDAP

Dear mayankkarki,

I have same requirement to authenticate with LDAP Password. But I used different class instead of DirectoryEntry since it is not working (ie I have authenticate against Lotus Notes LDAP). I used different class(NetworkCredential, LdapConnection ,SearchRequest, SearchResponse and SearchResultEntryCollection) and able to get list of user but I don't know authentication.

If u solved kindly guide me.

Let me also know if I use directry entry class, it through error like protocol error etc.

If I'm reading your question correctly, you have a Windows network login and a password, and you want to validate the user. Do you have to use LDAP?

This is what we use:

Public Function ValidateWindowsCredentials(ByVal UserId As String, _
ByVal Password As String) As Boolean
    Dim Result As Boolean = False

    Try
        Dim PC As New PrincipalContext(ContextType.Domain, "OurDomain")
        'This is done twice: sometimes, the first check fails.
        Result = PC.ValidateCredentials(UserId, Password, ContextOptions.Negotiate)
        Result = PC.ValidateCredentials(UserId, Password, ContextOptions.Negotiate)
    Catch ex As Exception
        Throw ex
    End Try

    Return Result
End Function

My apologies for it being in VB, but you should be able to translate this to C# easily enough. PrincipalContext is part of the System.DirectoryServices.AccountManagement namespace, which was added to the 3.5 Framework (Visual Studio 2008) and, in my experience, it is significantly faster than older technique of trying to change the password to itself.

As far as obtaining a password from a user id, you cannot: the property is write-only. This is by design, to prevent a malicious user from writing code that could harvest network passwords out of the AD data store.

Hi,
I am describing the way I used to connect and authenticate user in ldap. I have to connect over SSL and I am getting some problem with DirectoryEntry So I used LdapConnection class.

LdapConnection connection = new LdapConnection(new LdapDirectoryIdentifier("SJTPNOC.com", 636));
connection.SessionOptions.VerifyServerCertificate = new VerifyServerCertificateCallback((con, cer) => true);
connection.SessionOptions.ProtocolVersion = 3;        
connection.AuthType = AuthType.Basic;       
connection.SessionOptions.SecureSocketLayer = true;
connection.Timeout = new TimeSpan(0, 0, 10);   
connection.Credential = new NetworkCredential(username, password);
using (connection){}

If this doesn't throw error then user is authorised otherwise not. Now you have to be careful with username you provide.It must be user full domain name.
CN=mayank/OU=Users/dc=SJTPNOC/dc=com.
Let me know if anybody needs help.