Most web servers are smart enough to realize that there is no CGI by that name.
This reverse lookup means that the web server must ask the name server what the domain name for 206.117.169.69 is. Essentially, this is incurring two hits on the web server instead of one. Mal-formed link to Yahoo Not using trailing slashes can sometimes result in exposing the virtual hosting. Watch the location bar and you will see an example when you click the link below. When advertising a URL in print, you should use this format.