Q:

Syncing AD Security Groups to Office 365 to use in SharePoint

The organization that I work for has about 2400 employees who we will want to allow access to a site collection. However, only about 150 of those will have Office 365 licenses.
We would like to set this up using our AD Security Groups, but not sure if this is possible considering each non-licensed user would have to create some sort of microsoft account to login.
Has anyone dealt with a situation similar to this with a large organization, and how did you automate the process to add and remove users as needed.

A:

AD Security groups can be synced to Office 365 and used in permissioning SharePoint sites. We do it all over the place. To handle changes, you have to update your on prem groups, allow them to replicate through out your domain and the changes will be synced up the next time Azure AD Connect runs.
Our IT Security team handles the management of these groups through service requests that are submitted. 
If the users don't have licenses, they won't have access however. If they somehow do have access without licenses, you'd most likely be in violation of licensing terms, but you'd want to speak with your Microsoft TAM about this.

