Skype and LabVIEW WebServer

[hfettig]

Howdy Folks,

Just thought I'd share this little experience that cost me a few hours today. :headbang:

I wanted to try out the new web services in LabVIEW 8.6. So I started by turning on the LabVIEW web server.

When I tried out my first deployed web service I just got a blank page in Firefox. Interestingly enough in Internet Explorer I got a file not found error.

So after some searching I found the error.log file for the web server here: C:\Program Files\National Instruments\LabVIEW 8.6\resource\webserver\logs\error.log

In here I found out that LabVIEW was unable to create a connection on port 80 and therefore could not start the service. Good to know but why did this take this long to find out? Why is there no status LED on the Web Server panel in the Options dialog?

Next I tried to start the web server in LabVIEW 8.5.1. I thought that maybe there was a problem with the 8.6 web server (which is new) and VISTA. However, the 8.5.1 web server was unable to start as well, but at least I got a pop-up that told me this.

As a work-around I was able to turn on the web server in 8.6 on port 8080 with no problems.

Now the hard part was to find who was hogging port 80. After googling through a gazillion pages I found that in VISTA you can use the command NETSTAT -a -b -o -p TCP to find all active processes using TCP ports. And voila: Skype.exe was listed as listening on port 80.

After exiting skype LabVIEW WebServer started without problems on port 80 in both LV 8.5.1 and 8.6

Interestingly enough I was able to start skype after the LV WebServer was up and running. And I could thereafter shutdown and restart the LV WebServer without problems. However, if LV WebServer is not running and I restart Skype, then I run into the same problem all over again.

Now I found a setting in Skype under Options -> Advanced -> Connection called 'Use port 80 and 443 as alternatives for incoming connections'. After unchecking this Skype does not seem to block port 80 anymore. And I still seem to be able to receive calls (Thanks to Jim :thumbup: the test caller). This way I seem to be able to run Skype and LV WebServer at the same time.

So if you are having problems starting the LV web server, check your skype settings.

Cheers,

Heiko

[crelf]

I'm not sure if it was your intent, but your post kind-of sounds like you think that Skype using port 80 is a bad thing? I'm not sure it is. It's a chicken and egg problem: if you use Skype first then try to use something else that wants that port then it can be seen as a Skype problem...

[LAVA 1.0 Content]

QUOTE (hfettig @ Sep 12 2008, 04:09 PM)

...So if you are having problems starting the LV web server, ...

Cheers,

Heiko

Thank you Heiko! I learned a trick or three in that report!

Ben

[hfettig]

QUOTE (crelf @ Sep 15 2008, 10:35 AM)

I'm not sure if it was your intent, but your post kind-of sounds like you think that Skype using port 80 is a bad thing? I'm not sure it is. It's a chicken and egg problem: if you use Skype first then try to use something else that wants that port then it can be seen as a Skype problem...

I completely agree that this is more of a Skype problem than a LabVIEW problem. I just wanted to point out that this default Skype behaviour can lead to problems with LabVIEW and that it can be turned off.

[crelf]

QUOTE (hfettig @ Sep 15 2008, 02:38 PM)

I completely agree that this is more of a Skype problem than a LabVIEW problem.

That's not what I'm saying at all - I'm saying that it's a problem between the two, not necessarily due to one or the other.

[nhollenback]

Found this to be useful:

http://www.iana.org/assignments/port-numbers

Check out port 3363 :thumbup: