How can I verify that the DNN was configured correctly in DNS?

Use the Resolve-DnsName PowerShell command to see that the DNN has been configured correctly in DNS. See the following result for a 3 node cluster, where the DNN name dnnlsnr resolves to the three nodes:

Resolve-DnsName -Name dnnlsnr

Name                                     Type   TTL   Section    IPAddress
----                                     ----   ---   -------    ---------
dnnlsnr.acme.com                         A      1200  Answer     10.10.0.21
dnnlsnr.acme.com                         A      1200  Answer     10.20.0.20
dnnlsnr.acme.com                         A      1200  Answer     172.16.0.21