在C＃中使用FtpWebRequest时设置端口号

I keep getting a exception when I try to FTP to my Win 2008 Server from C# code using VS2008 as debugger.

当我尝试使用VS2008作为调试器从C#代码FTP到我的Win 2008服务器时,我一直遇到异常。

My test class looks like this:

我的测试类看起来像这样:

public class FTP
{
    private string ftpServerIP = "192.168.10.35:21";
    private string ftpUserID = "Administrator";
    private string ftpPassword = "XXXXXXXX";
    private string uploadToFolder = "uploadtest";

    public void Upload(string filename)
    {
        FileInfo fileInf = new FileInfo(filename);
        string uri = "ftp://" + ftpServerIP + "/" + uploadToFolder + "/" + fileInf.Name;
        FtpWebRequest reqFTP;

        reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
        reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
        reqFTP.KeepAlive = false;
        reqFTP.Method = WebRequestMethods.Ftp.UploadFile;
        reqFTP.UseBinary = true;
        reqFTP.ContentLength = fileInf.Length;

        int buffLength = 2048;
        byte[] buff = new byte[buffLength];
        int contentLen;

        FileStream fs = fileInf.OpenRead();
        try
        {
            Stream strm = reqFTP.GetRequestStream();
            contentLen = fs.Read(buff, 0, buffLength);

            while (contentLen != 0)
            {
                strm.Write(buff, 0, contentLen);
                contentLen = fs.Read(buff, 0, buffLength);
            }

            strm.Close();
            fs.Close();
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
    }
}

When I execute the code I get a Connection Failed with FTP error 227 in the GetRequestStream() call. In the exception I can see the connection fails to: 192.168.10.35:52184

当我执行代码时,我在GetRequestStream()调用中遇到FTP错误227的连接失败。在异常中我可以看到连接失败:192.168.10.35:52184

I have no idea how it comes up with port 52184. I specify in the ftpServerIP that it should be port 21.

我不知道如何使用端口52184.我在ftpServerIP中指定它应该是端口21。

I have found a few persons with the same issues on google but I haven't found a good example on how this is solved and I still don't understand why it happens.

我在谷歌上发现了一些有相同问题的人,但是我没有找到一个关于如何解决这个问题的好例子,我仍然不明白为什么会这样。

Anyone know how to handle this issue??

谁知道如何处理这个问题?

UPDATE:

I have tried to connect to a different FTP account and there it all works fine. Therefore I tested my 192.168.10.35:21 FTP but it works fine in CuteFTP Pro and the likes. This just makes it even more strange..

我曾尝试连接到不同的FTP帐户,并且一切正常。因此,我测试了我的192.168.10.35:21 FTP,但它在CuteFTP Pro和其他类似的工作正常。这让它变得更加奇怪..

3 个解决方案

#1

My guess would be Windows firewall issues, FTP uses other ports than just port 21 - sometimes changing the FTP mode from active to passive helps to get things working.

我的猜测是Windows防火墙问题,FTP使用的不仅仅是端口21的其他端口 - 有时将FTP模式从主动更改为被动有助于使事情正常工作。

reqFTP.UsePassive = false;

Look at this good article on FTP: Active FTP vs. Passive FTP, a Definitive Explanation

看看这篇关于FTP的好文章:主动FTP与被动FTP,一个明确的解释

#2

Thies got it right, it had to do with passive mode

他们做对了,它与被动模式有关

The fix in the code is so insanely simple :)

代码中的修复非常简单:)

reqFTP.UsePassive = false;

And it worked fast and without errors!

它工作得很快,没有错误!

#3

It is important to differentiate the COMMAND port and the DATA port. The connection protocol will also change depending if you are in ACTIVE or PASSIVE mode.

区分COMMAND端口和DATA端口很重要。如果您处于ACTIVE或PASSIVE模式,连接协议也会发生变化。

ACTIVE MODE :

活动模式:

1) The client initiate a connection from a random unspecified COMMAND port (N > 1023) to the default server COMMAND port (21). The client will specify his DATA port (N+1) and start listening on this port.

1)客户端发起从随机未指定的COMMAND端口(N> 1023)到默认服务器COMMAND端口(21)的连接。客户端将指定其DATA端口(N + 1)并开始侦听此端口。

2) The server initiate a connection from his default DATA port (20) to specified client DATA port (N+1).

2)服务器启动从其默认DATA端口(20)到指定客户端DATA端口(N + 1)的连接。

PASSIVE MODE :

被动模式:

1) The client initiate a connection from a random unspecified COMMAND port (N > 1023) to the default server COMMAND port (21) with the PASSIVE command. The server open a random DATA port (P > 1023) and send it to the client.

1)客户端使用PASSIVE命令从随机未指定的COMMAND端口(N> 1023)启动到默认服务器COMMAND端口(21)的连接。服务器打开一个随机的DATA端口(P> 1023)并将其发送到客户端。

2) The client initiate a connection from his DATA port (N+1) to the specified server DATA port (P > 1023).

2)客户端启动从其DATA端口(N + 1)到指定服务器DATA端口的连接(P> 1023)。

If you use ACTIVE mode, you will most likely need to let your client's firewall accept the connection from the server to your port (N+1 > 1024).

如果使用ACTIVE模式,则很可能需要让客户端的防火墙接受从服务器到端口的连接(N + 1> 1024)。

In your example, you were in ACTIVE mode. Your client initiated a connection from his COMMAND port (52183) to the server's default COMMAND port (21) and specified its DATA port (52184 = 52183 + 1). Then the server initiated a connection from its default DATA port (20) to the client's DATA port (52184) which was most likely rejected by the client's firewall.

在您的示例中,您处于ACTIVE模式。您的客户端从其COMMAND端口(52183)启动了到服务器的默认COMMAND端口(21)的连接,并指定了其DATA端口(52184 = 52183 + 1)。然后,服务器启动从其默认DATA端口(20)到客户端的DATA端口(52184)的连接,该端口很可能被客户端的防火墙拒绝。

I hope this helps you solve your problem!

我希望这可以帮助您解决问题!

#1