Lync 2013 and IPv6

Microsoft Lync Server 2013 supports the use of IPv6 addressing. To use IPv6 addresses, you must also provide support for IPv6 DNS and configure DNS host AAAA (known as “quad-A”) records. In deployments where both IPv4 and IPv6 are being used, it is best to configure and maintain both host A records for IPv4 and host AAAA for IPv6. Even if your deployment has transitioned fully to IPv6, IPv4 DNS host records may still be required when external users are still using IPv4.