System.DirectoryServices.Protocols
名前空間を使用して、次のようなことを試してください。
//Define your connection
LdapConnection ldapConnection = new LdapConnection("123.456.789.10:389");
try
{
//Authenticate the username and password
using (ldapConnection)
{
//Pass in the network creds, and the domain.
var networkCredential = new NetworkCredential(Username, Password, Domain);
//Since we're using unsecured port 389, set to false. If using port 636 over SSL, set this to true.
ldapConnection.SessionOptions.SecureSocketLayer = false;
ldapConnection.SessionOptions.VerifyServerCertificate += delegate { return true; };
//To force NTLM\Kerberos use AuthType.Negotiate, for non-TLS and unsecured, use AuthType.Basic
ldapConnection.AuthType = AuthType.Basic;
ldapConnection.Bind(networkCredential);
}
catch (LdapException ldapException)
{
//Authentication failed, exception will dictate why
}
}