Enable reverse dns resolution for cti

Solution
http://support.microsoft.com/kb/297795

IIS 4.0

1.  Open a command prompt.
2.  Change the folder to %systemroot%\Inetsrv\Adminsamples.
3.  Type adsutil set w3svc/EnableReverseDNS TRUE, and then press ENTER.

IIS 5.0 and Later

1.  Open a command prompt.
2.  Change the folder to C:\Inetpub\Adminscripts.
3.  Type adsutil set w3svc/EnableReverseDNS TRUE, and then press ENTER.