Fiddler無法捕獲HttpWebRequest請求，且請求失敗

用C# HttpWebRequest模擬請求時，如果打開Fiddler則請求超時且Fiddler無法捕獲，而把Fiddler關閉就可以正常訪問。

 

答案為：HttpWebRequest 請求頭的Host頭不要設置任何內容，注釋即可訪問，而非設置代理問題

 

 

HttpWebRequest req = (HttpWebRequest)WebRequest.Create(urlToCrawl);
            req.Method = "GET";
            req.UserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.117 Safari/537.36";
            //req.Host = host;
            req.Referer = referer;
            req.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8";
            req.Headers.Add("Accept-Encoding", "gzip,deflate,sdch;");
            //req.Proxy = WebProxy.GetDefaultProxy();
            //req.Proxy = new WebProxy("127.0.0.1:8888", true);

            HttpWebResponse resp = (HttpWebResponse)req.GetResponse();
            string htmlCharset = "GBK";
            Encoding htmlEncoding = Encoding.GetEncoding(htmlCharset);
            //StreamReader sr = new StreamReader(new GZipStream(resp.GetResponseStream(), CompressionMode.Decompress), htmlEncoding);
            StreamReader sr = new StreamReader(resp.GetResponseStream(), htmlEncoding);
            string respHtml = sr.ReadToEnd();