Which are the top three free open source active directory alternatives for Microsoft Active Directory? Are there any substitutions for Microsoft Active directory for free?

Can I send an email using Office 365 SMTP relay or Exchange online? What are the requirements and limitations of using the Office 365 SMTP relay?

What are the various Office 365 nonprofit pricing products? Why should one pay for the Office nonprofit packages when there are free or donation packages also?

How can I use the Exchange admin center for the Office 365 litigation hold? What is the procedure to place Office 365 on litigation hold?

What is the procedure to add more people contact information to the Office 365 global address list? How to manage and update the global address list?

What is the procedure to back up the emails in the computer? Can anyone help me make Microsoft Office 365 email backup to my local PC?

I am receiving errors missing AAAA record at DNS server while executing dcdiag /test:dns. How can I resolve this issue? How to disable the IPv6 on Windows completely?

How can I migrate exchange 2010 to 2013 server? Can I keep both the exchange 2010 and 2013 forever? Can I directly update exchange 2003 to 2013?

Should I start using any other anti-virus rather than the recommended Microsoft Security Essentials? Can anyone give me the genuine Microsoft Security Essentials Review 2014?

What are the minimum system requirements to install the Microsoft Report Viewer 2008 sp1 Redistributable? What is included in the redistributable package of the Microsoft Report Viewer?