Adding IP address like host header in IIS 8 shows UI validation error, this worked fine in IIS 7.5 and earlier

There are situations where we have the site specified like below in several configurations, for example like in GPO we specify the location of the Automatic Proxy Configuration script to be at location:, so to make this not depending on the availability of DNS resolving.

In IIS7, we could register the IP address as hostname. If we do this in IIS8, I get the failure message:

Edit Site Binding
The specified host name is incorrect. The host name must use a valid host name format and cannot contain the following characters: "/\[]:|<>+=;,?*$%#@{}^`. Example:


This is by design in IIS 8 UI. Hence we wont be able to skip this from UI. Though as a workaround you can directly edit applicationhost.config from  %SystemRoot%\system32\inetsrv\config folder. Please do take a back up of this file before directly editing. Once backed up, open applicationhost.config file in notepad. Try finding the bindings something like and add it manually:

 <site name="mstest" id="4" serverAutoStart="true">
                <application path="/" applicationPool="mstest">
                    <virtualDirectory path="/" physicalPath="C:\inetpub\wwwroot" />

                    <binding protocol="http" bindingInformation="*:80:mydomainnamedotcom" />
                    <binding protocol="http" bindingInformation="*:80:" />

 This seems to work in my black box testing. Let me know if any comments or suggestions.


~ Devendra Asane