Error 56 occurred at TCP Wait On Listener

[Ashbaernon]

Hello all,

I'm trying to get FTP working from within labview using the FTP modules from the internet toolkit.

Here's my scenario:

I have an FTP server running on my local PC.
I have an FTP server running on my linux laptop.
I have access to my ISPs FTP server.

I am able to log into each of these using the correct port and address details from any FTP client.
I am able to use Labview to connect and get/put files from my local FTP server (localhost, 127.0.0.1).

But I am unable to get/put files from either the Linux FTP server laptop nor the ISP FTP server.

The Linux FTP server gives the following error message when trying to get the file:

Error 56 occurred at TCP Wait On Listener in FTP Open Data Connection.vi->FTP Data Receive.vi->FTP [RETR].vi->FTP Retrieve Multiple.vi->FTP Get Multiple Files and Buffers.vi->FTP Get File.vi->Untitled 2

The ISP FTP server gives a different error message:

Error 0 occurred at FTPOpen Data Connection:  Could not establish connection

I have made some attempts to look deeper into the FTP VIs and check the error clusters for the point where each error occurs but I'm a little lost at this point.

So are there any guru's here who can help me?

Cheers,

Ash.

ps: the paths are correctly configured using unix syntax for the server and dos syntax for the client.

[Ray.R]

Have you looked at this thread?

or this one?

Jaime proposes similar suggestions here

Summary:

"This is a timeout error normally, because of that probably are the settings of your TCP/IP or the communication which are wrong:

1. Ensure u got no antivirus/firewall working that can block the communication.

2. Review that u ar pointing to the DNS server properly on your TCP/IP configuration, if you want to be sure try changing the computer name for an IP address (that is instead of using dstp://ordenador-1/variable use dstp://192.39.39.45/variable for example).

3. Try increasing the timeout.

4. Be sure Datasocket server is working on the PC you got the variable

5. Try using DS examples on your PC (just one) introducing localhost or 127.0.0.1"

More suggesting a network timeout error.

[Ashbaernon]

Yeah I've got connectivity so firewall isn't the issue. I can do it all through filezilla, firefox, "insert FTP client here" without problems. It's only when using the VI the problem occurs.
DNS, not an issue. I'm using IPs and even if I was using hostnames my DNS is configured correctly.
Timeout not an issue. I'm running 100Mbps LAN to my laptop FTP. Using other FTP clients the file is transferred in fractions of a second.
I'm not using datasocket...should I be? I am able to connect to a local FTP no problem so I wouldn't have thought that an issue...

Perhaps this is the issue. I have some datasocket examples that I will check.

Otherwise I'm quite perplexed. I am running LV8.5 btw...

Thanks for the quick reply 🙂

Ash.

[Ashbaernon]

OK I looked into using datasocket. It's not needed for FTP using the internet toolkit.

I delved deeper into the VI "FTP Open Data Connection.vi" and enabled debugging and here's what I can tell you.

The TCP listener is receiving the listener ID generated by "TCP Create Arbitrary Listener.vi".
"TCP Create Arbitrary Listener.vi" is opening a free port.
The case structures are all true indicating that the connection is active.
I am seeing replies from the FTP server in the respective indicators.
"FTP Check Reply.vi" is matching to the specified "100 + prelim" class and giving the go ahead for a TCP connection to be established.

I'm stuck at this point.

Anyone here got any more ideas?

Cheers,

Ash.

[Ray.R]

Sorry, I should have removed items 4 & 5 from the summary list.  You are correct that you don't need datasockets.  I copy / pasted too fast. 

Reading your original post it looks like the root problem is actually at the Open Connection.

Error 56 occurred at TCP Wait On Listener in FTP Open Data Connection.vi->FTP Data Receive.vi->FTP [RETR].vi->FTP Retrieve Multiple.vi->FTP Get Multiple Files and Buffers.vi->FTP Get File.vi->Untitled 2

The ISP FTP server gives a different error message:

Error 0 occurred at FTPOpen Data Connection:  Could not establish connection

Have a look at JR's vi in this thread. http://forums.ni.com/ni/board/message?board.id=170&message.id=38517&query.id=96588#M38517

Something else to consider and you may want to start hers is: 

Are you using an active or inactive connection? Sometime one will work but not the other, so if you are using active try inactive or vice versa.

Apparently, FTP uses two ports: one to send commands, the other to send data.  The difference in active and inactive is who opens the data connection to transfer the file.