TCP error 60 on W7

[Dave_Thomson]

I have a LV 2010 program that implements a simple FTP client.  I build it on W7.  It worked for months.  Then, on my W7 machine, I started getting error 60 (LabVIEW:  The specified network address is currently in use.) every time the FTP Open Session.vi runs, from the TCP Open Connection function.  I get error 60 no matter what IP address I use.  If I use the same IP address in a regular commercial FTP client, it is fine.  (Yes, I close the FTP client and everything else when I run my LV program.)  I've tried turning off my firewall.  No luck.  The program still works as an executable on other machines.  Until today - another W7 machine started exhibiting the same symptom.  Any ideas what W7 setting could be getting set (maybe with auto-updates) that could cause LV to fail a TCP-IP connection, but Filezilla and other FTP programs still work?

Thanks in advance,

   DaveT

[Brian-G]

Hi Dave,

Error 60 occurs when the port on the local or remote machine is already being used. Here are a couple of things to try:

1. Try to reopen LabVIEW or restart your computer to make sure no previous instances of the program are still using the port.

2. Configuring your client and server to use a different port on your machine. You can check which ports are being used by running Windows cmd and typing in "netstat -an" without quotes.

3. Test the connection on your local machine by using the examples "Named Service TCP Server.vi" and "Named Service TCP Client.vi" from "Help->Example Finder->Networking->TCP & UDP". This will setup a simple TCP/IP client/server setup on localhost. The example's default configuration is to allow Windows to automatically find an open port for you.

If these options don't resolve your issue, the following information would be helpful:

1. How are these machines connected? Directly via crossover cable, over a hub, or on a local network? Has this connection changed recently?

2. Are you opening and closing TCP connections repeatedly in your VI? Sometimes it takes a little while for programs to release the port from use.

3. Is your network equipment dynamically changing your the IP addresses of your machines? Although I doubt this would be the issue because you should get a different error.

Good luck!

[Dave_Thomson]

   Although Error 60 claims that the IP address is already in use, it turns out that this problem was due to the local port already being in use.  I had wired a value to the Local Port input of the TCP-IP Open Session function.  At one time, the port was available and things worked fine.  At some point, some other program on my computer decided to use that port.  Deleting that input (which apparently tells it to automatically find an available port) resolved the issue.

DaveT

[PhillipBrooks]

Helpful for determining the cause of port conflicts:

http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers

[Brian-G]

Hi Dave,

I'm glad you were able to get the program working on a different port.  Sorry for the misinformation in the error code, and thank you for bringing it to our attention.  I have submitted a Corrective Action Request to the development team to correct the dialog in the error message to include the "port at the requested network address is in use".

Brian