Automatic Client Sign-in

Although the sample DNS configurations just shown can be used to meet the minimum requirements for Lync, many organizations rely on the Lync client’s capability to automatically find the Lync pool and sign in the user, an optional but very useful feature. To provide automatic client sign-in, an SRV record is required for _sipinternaltls._tcp.<domain> over port 5061 that maps to the fully qualified name of the pool. For example, Figure 11.4 shows the configuration of the SRV record that would be added to the sample DNS configuration shown previously to provide automatic client sign-in for the companyabc.com Lync deployment.

Figure 11.4. SRV record used for automatic client sign-in.

Note that SRV records hold information that is not used with other types of DNS records, such as priority, weight, and port number. In addition to specifying the location of the service, this information provides a means to influence how the incoming traffic load will be shared or directed.