Below is an example of a website that when requested from my local dev environment returns ok but when requested from the production server, the request times out after 15 seconds. The request headers are exactly t开发者_StackOverflow中文版he same. Any ideas?

http://www.dealsdirect.com.au/p/wall-mounted-fish-tank-30cm/

Here's one thing that I wanna point beside what other stuff I've already provided. When you call GetResponse the object that's returned has to be disposed of ASAP. Otherwise stalling will occur, or rather the next call will block and possibly time out because there's a limit to the number of requests that can go through the HTTP request engine concurrently in System.Net.

// The request doesn't matter, it's not holding on to any critical resources
var request = (HttpWebRequest)WebRequest.Create(url);

// The response however is, these will eventually be reclaimed by the GC
// but you'll run into problems similar to deadlocks if you don't dispose them yourself
// when you have many of them
using (var response = request.GetResponse())
{
    // Do stuff with `response` here
}

This is my old answer

This question is really hard to answer without knowing more about the specifics. There's no reason why the IIS would behave like this which leads me to conclude that the problem has to do with something you app is doing but I know nothing about it. If you can reproduce the problem with a debugger attached you might be able to track down where the problem is occuring but if you cannot do this first then there's little I can do to help.

Are you using the ASP.NET Development Server or IIS Express in development?

If this is an issue with proxies here's a factory method I use to setup HTTP requests that require where the proxy requires some authentication (though, I don't believe I ever received a time out):

HttpWebRequest CreateRequest(Uri url)
{
    var request = (HttpWebRequest)WebRequest.Create(url);
    request.Timeout = 120 * 1000;
    request.CookieContainer = _cookieContainer;
    if (UseSystemWebProxy)
    {
        var proxy = WebRequest.GetSystemWebProxy();
        if (UseDefaultCredentials)
        {
            proxy.Credentials = CredentialCache.DefaultCredentials;
        }
        if (UseNetworkCredentials != null
            && UseNetworkCredentials.Length > 0)
        {
            var networkCredential = new NetworkCredential();
            networkCredential.UserName = UseNetworkCredentials[0];
            if (UseNetworkCredentials.Length > 1)
            {
                networkCredential.Password = UseNetworkCredentials[1];
            }
            if (UseNetworkCredentials.Length > 2)
            {
                networkCredential.Domain = UseNetworkCredentials[2];
            }
            proxy.Credentials = networkCredential;
        }
        request.Proxy = proxy;
    }
    return request;
}

Try this out Adrian and let me know how it goes.