Network and directory server requirements for Exchange 2016

Component	Requirement
Domain controllers	All domain controllers in the forest need to be running one of the following: Windows Server 2012 R2 Standard or Datacenter Windows Server 2012 Standard or Datacenter Windows Server 2008 R2 Standard or Enterprise Windows Server 2008 R2 Datacenter RTM or later Windows Server 2008 Standard, Enterprise, or Datacenter
Active Directory forest	The Active Directory forest functionality level needs to be at Windows Server 2008 or higher.
DNS namespace support	Exchange 2016 supports the following domain name system (DNS) namespaces: Contiguous Noncontiguous Single label domains Disjoint For more information about DNS namespaces supported by Exchange, see Microsoft Knowledge Base article 2269838, Microsoft Exchange compatibility with Single Label Domains, Disjoined Namespaces, and Discontiguous Namespaces.
IPv6 support	In Exchange 2016, IPv6 is supported only when IPv4 is also installed and enabled. If Exchange 2016 is deployed in this configuration, and the network supports IPv4 and IPv6, all Exchange servers can send data to and receive data from devices, servers, and clients that use IPv6 addresses. For more information, see IPv6 support in Exchange 2013.