WS toolkit and Secuired Webservice

[Hiten]

I am working on this web service and came across an issue, and I thought,
someone might be able to throw some light.

The webservice is configured to allow Authenticated users only and deny all
Anonymous users in web.config. Also, I have enabled Impersonation in
config file and using Windows authentication.

On IIS, I have created virtual folder and in directory security, I have set
Anonymous and Integrated Windows authentication both enabled (checked).

Now when I use the HostName in URL (http://host1/test.asmx) to add
webservice reference in excel, it detects the service and adds the reference,
however, when I use box's IP address (http://10.1.10.1/test.asmx), it does
not detect the webservice at all.

To check,I used the same url in IE, on the first one it displays the
page,however, on the second url it asks me for login information (UserName
and Password), And if i provide valid login information, it displays WS
methods else it throws access denied error.

Can someone tell me what do i have to configure to get this reference from
excel web reference?

Thanks,
Hiten