try to configure IIS to do a reverse DNS lookup, but it will affect the performance, seeHOW TO: Enable Reverse DNS Lookup for IIS
http://support.microsoft.com/?scid=kb;en-us;q297795
http://support.microsoft.com/?scid=kb;en-us;q297795
Open a command prompt.
Change the folder to %systemroot%\Inetsrv\Adminsamples.
Type adsutil set w3svc/EnableReverseDNS TRUE, and then press ENTER.
back to the top
IIS 5.0 and IIS 5.1
Open a command prompt.
Change the folder to C:\Inetpub\Adminscripts.
Type adsutil set w3svc/EnableReverseDNS TRUE, and then press ENTER.