Welcome back to our two-part series on how to enable secure LDAP (LDAPS) communications between client/server applications on Windows Server 2008/2012 domain controllers. In part one, I went over what you should know about LDAPS, your options, and prerequisites. After we understood the concepts of why, where and when we should be looking to use LDAPS, let’s move on to the actual configuration.
1. Create the right certificate template to issue
First, we need to make sure that your CA is allowed to issue the correct types of certificates. Remember, these must contain the Server Authentication OID 184.108.40.206.220.127.116.11.1.
I’ve described the steps you need to take in order to create such a template in my Creating a Digital Certificate Template for the purpose of Server Authentication in Windows Server 2008/R2/2012 article.
2. Request a certificate for server authentication
To request a certificate from your LDAPS server, do the following on each DC that requires LDAPS connections:
Note: If you plan to have more than one digital certificate for that DC, and if you are using Windows Server 2008/R2/2012, please read this following article BEFORE you proceed: The issue with Active Directory Domain Services (NTDS\Personal) certificate store
If you only plan to have one digital certificate on that DC, please proceed to the next step.
In Certificate Enrollment, click Next.
In the Select Certificate Enrollment Policy, choose Active Directory Enrollment Policy (default) and click Next.
Click the Details tab. In the Field column, go ahead and select Enhanced Key Usage. You’ll want to confirm that the Server Authentication (18.104.22.168.22.214.171.124.1) is listed.
To test if LDAP over TLS works properly, use the ldp.exe tool.
Note: If ldp.exe is not available on your system, you will need to install the Active Directory Directory Services (AD-DS) management tools from the Windows Remote Server Administration Kit (RSAT):
After the procedure, note that “Host supports SSL, SSL cipher strength = 128 bits”.
Note: If you try to connect to the right DC but do not use the same FQDN as was listed inside the issued certificate (for example, using the IP address instead), you will not be able to connect using LDAPS.
The command output should display the user name and domain name that you used for binding, if LDAPS is configured properly. You can start browsing through the AD tree.
If you use the command: netstat -no | find “:636”, you will find the connection to the DC.