The LDAP server is unavailable after installing KB2868725

Question

After installing the KB2868725 Windows Update, a strange LDAPs connection problem occur.
Context : we have a C# web site (.NET 4.0) that perform an LDAPs Bind operation over LDAPs. The web server is not on the same domain (bind operations are perform again multiple LDAPs Server), and the code work like a charm more than a year.
So after installing the KB2868725 Windows Update we get a “System.DirectoryServices.Protocols.LdapException: The LDAP server is unavailable.” exception from the same application. When we uninstall the update, the error stop.
The problem is present ONLY over a SECURE connection.
We have multiple web server in production and every server where the KB2868725 Windows Update is not installed are working perfectly.
We build a test application with this simple code, work fine on “non-KB2868725 updated server”:
void BindLDAP()
LdapDirectoryIdentifier ldi = new LdapDirectoryIdentifier("example.com", 636, true, false);
LdapConnection ldapCnn = new LdapConnection(ldi, new NetworkCredential("myUsername", "myPassword"), AuthType.Basic);
ldapCnn.SessionOptions.VerifyServerCertificate = new VerifyServerCertificateCallback(Validate);
ldapCnn.Bind();
private static bool Validate(LdapConnection connection, X509Certificate certificate) { return true; }
Stack trace:
System.DirectoryServices.Protocols.LdapException: The LDAP server is unavailable.
at System.DirectoryServices.Protocols.LdapConnection.Connect()
at System.DirectoryServices.Protocols.LdapConnection.BindHelper(NetworkCredential newCredential, Boolean needSetCredential)
Server: Windows Server 2008 R2 Standard, Service Pack 1 (64-bit)
We tried to change every connections settings, change .NET version (2.0, 3.5 and 4.0), build the test application directly on the server and nothing work.
If we use others LDAP tool (like http://technet.microsoft.com/en-us/sysinternals/bb963907.aspx) the problem also occur : “The server is not operational.”
Moreover, if we installed these updates the problem also occur: KB2574819, KB2830477, KB2871997, KB2592687.
We can’t install any Windows Updates, that’s a problem. We would like to find a solution, please help us ;-)

Answer 1

Hi,
The server is configure to get the Windows Update from a WSUS server. Those updates are downloaded from Microsoft. 
I follow these steps:
1. Uninstall Windows Update : KB2574819, KB2830477 (KB2857650) and KB2913751;
2. Perform a LDAP connection test : work perfectly;
3. Install Update KB2574819;
4. Perform a LDAP connection test : not working (The LDAP server is unavailable.);
5. Install Update KB2830477 (KB2857650 is include in KB2830477 update);
6. Perform a LDAP connection test : not working (The LDAP server is unavailable.);
7. Install Update KB2913751;
8. Perform a LDAP connection test : not working (The LDAP server is unavailable.);
The problem here is we can’t install KB2574819, KB2830477 (KB2857650) and KB2913751 on our productions servers because of the connections problems (install process work fine, is the effects of these Windows Updates).
Philippe Bernier