Microsoft DirectAccess is purely based on IPV6 and Lync 2013 is fully supporting IPV6 and Lync 2013 clients using DirectAccess should work without any problem.
If any one encountered problems making Lync calls or connecting to Lync on a DirectAccess Computer then you need to ensure that IPV6 is enabled on the Lync 2013 Server as per the below image.
This can be achieved as follows:
- Open the Lync 2013 Topology Builder from an old file or download the topology
- Edit the properties of the Lync server and in the General Properties ensure that IPV6 is enabled.
- These settings need to be published from the Action Menu - Topology - Publish
Now you can enjoy Lync 2013 over DirectAccess Connection.