Submitted by: Graham Cobb , Project Manager at PTG, a Microsoft Tier 3 Cloud Champion, Cloud Accelerate partner and Cloud deployment partner providing technology solutions including Office 365, Dynamics CRM, Private Cloud, and IT Infrastructure to businesses and enterprises nationally.

If you are using Lync inside Office 365, it is very easy to enable your users to communicate with other Office 365 users as well as Skype users.  You need to be an Office 365 administrator to perform this function.  Log into the Office 365 admin center and navigate to the Lync administration section.  Once you are there, choose the Organization tab, and then set the value in the drop down to your preferred setting.  You have three options: