Question

I want to block access to a url from everything except for iis usr that requests the image.

So I have: www.myurl.com/somedirectory/myfile.ashx

I want only my requests from code behind to be able to access this file not users/bots/non-clients who can manually visit the file by going to the url.

Need to take into account that servers are load-balanced I am unsure if this will cause an issue.

How would I go about doing this.

Requested serverside:

HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create(imageUrl);
httpRequest.Method = "GET";
httpRequest.UserAgent = "MobileQ.NET";
httpRequest.ContentType = "image/png";
response = httpRequest.GetResponse().GetResponseStream();

Answer 1

You can check in your myfile.ashx if the request is from localhost:

string client = HttpContext.Current.Request.ServerVariables["REMOTE_ADDR"];
if(client == "localhost" || client == "127.0.0.1" || client == "::1")
    //DoWork
else
{
    HttpContext.Current.Response.StatusCode = (int)HttpStatusCode.Forbidden;
    return;
}