![Active Directory: LDAPs(636) and MSFT-GC-SSL(3269) Service - TechNet Articles - United States (English) - TechNet Wiki Active Directory: LDAPs(636) and MSFT-GC-SSL(3269) Service - TechNet Articles - United States (English) - TechNet Wiki](http://social.technet.microsoft.com/wiki/cfs-file.ashx/__key/communityserver-wikis-components-files/00-00-00-00-05/38087.1.png)
Active Directory: LDAPs(636) and MSFT-GC-SSL(3269) Service - TechNet Articles - United States (English) - TechNet Wiki
Sophos Email Appliance: Configure AD/LDAP authentication over SSL/TLS according to Microsoft's recommendation
![ldp.exe LDAPS Cannot open connection Error 81 | vGeek - Tales from real IT system Administration environment ldp.exe LDAPS Cannot open connection Error 81 | vGeek - Tales from real IT system Administration environment](http://vcloud-lab.com/files/resized/664213/500;254;10984c20f28a7be2a1ed5cccdda4bacde1ed9296.png)
ldp.exe LDAPS Cannot open connection Error 81 | vGeek - Tales from real IT system Administration environment
![Active Directory: LDAPs(636) and MSFT-GC-SSL(3269) Service - TechNet Articles - United States (English) - TechNet Wiki Active Directory: LDAPs(636) and MSFT-GC-SSL(3269) Service - TechNet Articles - United States (English) - TechNet Wiki](http://social.technet.microsoft.com/wiki/cfs-file.ashx/__key/communityserver-wikis-components-files/00-00-00-00-05/7220.reg.png)
Active Directory: LDAPs(636) and MSFT-GC-SSL(3269) Service - TechNet Articles - United States (English) - TechNet Wiki
![How to figure out which open ports or services are insecure? - Well known and registered ports and their corresponding applications How to figure out which open ports or services are insecure? - Well known and registered ports and their corresponding applications](https://i0.wp.com/docs.microsoft.com/answers/storage/attachments/17636-11.png)