問題描述
底層連接已關閉：接收時發生意外錯誤 (The underlying connection was closed: An unexpected error occurred on a receive)
When I try my program on my win2k8 machine it runs fine but on win 2k3 it gives me this error that error message
here's the code that' generating the error
WebClient wc = new WebClient();
wc.DownloadFile("ftp://ftp.website.com/sample.zip");
there's the weird part. if i disable the firewall on the server completely. the error goes away. but it still errors if i add the program to the exception list and turn on the firewall.
have search the web for days, couldn't find any solution.
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參考解法
方法 1:
You should try using passive mode for FTP. The WebClient class doesn't allow that, but FtpWebRequest does.
FtpWebRequest request = WebRequest.Create("ftp://ftp.website.com/sample.zip") as FtpWebRequest;
request.UsePassive = true;
FtpWebResponse response = request.GetResponse() as FtpWebResponse;
Stream ftpStream = response.GetResponse();
int bufferSize = 8192;
byte[] buffer = new byte[bufferSize];
using (FileStream fileStream = new FileStream("localfile.zip", FileMode.Create, FileAccess.Write))
{
int nBytes;
while((nBytes = ftpStream.Read(buffer, 0, bufferSize) > 0)
{
fileStream.Write(buffer, 0, nBytes);
}
}
方法 2:
Please post the complete exception, including any InnerException:
try
{
WebClient wc = new WebClient();
wc.DownloadFile("ftp://ftp.website.com/sample.zip");
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString()); // Or Debug.Trace, or whatever
throw; // As if the catch were not present
}
方法 3:
I had a similar issue (no ftp) and a different solution
The production server environment had been made so secure that the server could not reach the URL.
Quick test is to use a browser on the box and see if you can navigate to the url.
Hope this helps someone.
(by chat、Thomas Levesque、John Saunders、Tim Jarvis)