Unable to use external proxy in c# HttpWebRequest

Question

i am hitting this url:

http://www.google.co.uk/search?q=online stores uk&hl=en&cr=countryUK%7CcountryGB&as_qdr=all&tbs=ctr:countryUK

Basically i get the ppcUrls, it works perfect without any proxy.

But when i try to use a proxy which are available on the internet:

http://proxy-list.org/en/index.php?pp=3128&pt=any&pc=any&ps=any&submit=Filter+Proxy

The above link wont open in any way :|, i did check the ipz with the internet explorer and it opened , but here in HTTPWEBREQUEST , sometime i get 503 Server unavailable, or Too Many redirections

The link wont open with any ip .

Any suggestion ? Below is my getting HTML function:

   public string getHtml(string url, string proxytmp)
    {
        string responseData = "";
        try
        {


            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            request.Accept = "*/*";
            request.AllowAutoRedirect = true;
            request.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.2; .NET CLR 1.0.3705;)";
            request.Timeout = 60000;
            request.Method = "GET";

            if (proxies.Count > 0)
            {
                try
                {
                    int customIP = 0;
                    int port = 0;
                    string ip = string.Empty;

                    string[] splitter = proxytmp.Split(':');
                    if (splitter.Length > 0)
                    {

                        ip = splitter[0].ToString();
                        port = Convert.ToInt32(splitter[1].ToString());
                    }

                    WebProxy proxy = new WebProxy(ip, port);
                    request.Proxy = proxy;

                }
                catch (Exception exp)
                {

                }
            }

            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            if (response.StatusCode == HttpStatusCode.OK)
            {
                Stream responseStream = response.GetResponseStream();
                StreamReader myStreamReader = new StreamReader(responseStream);
                responseData = myStreamReader.ReadToEnd();
            }
            response.Close();


        }
          catch (System.Exception e)
        {
            responseData = e.ToString();
        }

        return responseData;

    }

UPDATE

The Url opens when i use the same proxy with Internet explorer so there must be a way.But i cannot figure it out.

Thank you

Answer 1

My guess is that the proxy blocks incoming connections of a certain nature and that is why you are running into various issues and these checks might be complex in nature or it might be as simple as setting the User-Agent to a valid browser.. I am not sure what other things a proxy can check, I would suggest you take a look at the request object created (something like Referrer, Port etc ) when you use your browser to make the request and make changes accordingly in your C# code..

Good luck, let me know how it works out for you.