A useful feature in Lync Server 2013 is the concept of draining a server when preparing it for maintenance. This enables an administrator to prepare a server for maintenance without immediately affecting users. Existing sessions on the server are ended immediately and users are transferred to a different server within the pool.
To prepare a server for maintenance, follow these steps:
1. Open the Lync Server Control Panel.
2. Click Topology.
3. Highlight the server to be modified.
4. Click Action and select Prevent New Connections for All Services.
5. Alternatively, double-click the server to drill down further and manage the individual services.
Preventing new connections is a feature that only works with DNS load balancing ...