IIS Express – HTTP Error 400. The request hostname is invalid.

November 2, 2013 / Kannan / 6 Comments

The following is the fix for the error “HTTP Error 400. The request hostname is invalid” when trying to browse an IIS Express site using a different host name or IP address.

1. Exit the IIS Express instant currently running.

2. Open IIS Express’s applicationhost.config located at the following path C:\Users\<user>\Documents\IISExpress\config\applicationhost.config

3. Find the entry for a particular site (e.g “Test” running in port 6306) which you are developing.

e.g.

<site name="FlickrTest" id="10">
    <application path="/" applicationPool="Clr4IntegratedAppPool">
        <virtualDirectory path="/" physicalPath="E:\Projects\BB Apps\FlickrTest" />
    </application>
    <bindings>
        <binding protocol="http" bindingInformation="*:6306:localhost" />
    </bindings>
</site>

4. Replace the following

bindingInformation=”*:6306:localhost” with bindingInformation=”*:6306:*”

5. Save the file.

6. Start a command prompt in administrator mode and run the following command.

netsh http add urlacl url=http://*:6306/ user=Everyone

7. Now debug the site again and you should be able to access the url using IP address or host name.