How to enable online archive in Hybrid Exchange

https://social.technet.microsoft.com/wiki/contents/articles/51966.office-365-hybrid-enabling-in-place-archive-with-powershell.aspx

Sharepoint search error The item could not be indexed successfully because the item failed in the indexing subsystem.

https://docs.microsoft.com/en-us/archive/blogs/sp/clear-sharepoint-config-cache-with-powershell

http://bresleveloper.blogspot.com/2016/01/solved-item-could-not-be-indexed.html

in general

https://docs.microsoft.com/en-us/archive/blogs/sp/
https://blogs.msdn.microsoft.com/sharepoint_strategery/2014/12/04/sp2013-understanding-storage-locations-for-files-gathered-by-the-crawl-component/

is a good Knowledge base to keep in mind!

a tool to check Web site security from Mozilla

https://observatory.mozilla.org/

script to for TLS hardening in Windows servers

https://www.hass.de/content/setup-microsoft-windows-or-iis-ssl-perfect-forward-secrecy-and-tls-12