What Are Distribution Groups in Exchange Server 2013?

           Distribution groups in Exchange Server are mail enabled groups. When you mail-enable a group, Exchange Server 2013 assigns an email address to the group, and the group by default is added to the GAL. You can use mail-enabled groups to allow users to send email to multiple recipients.
           Mail-enabled security groups also allow you to assign permissions simultaneously to multiple users for Exchange Server objects, such as shared mailboxes and public folders.
           In Exchange Server 2013, you can create two types of mail-enabled groups:
• Universal security groups. Universal security groups in AD DS are used to assign permissions to
network resources, and are used as an Exchange Server 2013 distribution group.
• Universal distribution groups. Universal distribution groups in AD DS can only be used to group email recipients; they cannot be used to assign permissions to network resources.