NIPXISM port conflict

[TucsonDave]

NIPXISM.EXE seems to grab ports starting at a certain number and sometimes grabs a port I need for other purposes.  Can I tell it to not grab a particular port or start grabbing a different series?

[Wild_man]

Using NetStat -b in windows command prompt I found the following 9 ports associated with NIPXISM.exe

31075
31076
31077
32191
32192
32975
32976
63104
63105

31075 appears to communicate with Device Monitor and nimxs.exe (MAX) while the other 8 appear to communicate to each other in pairs. Given that this is internal to the application I suspect they are not configurable, but I have not verified this yet.

Which ports are conflicting with other programs and is it possible to configure the other programs?

[TucsonDave]

Port 49185 is my conflict. 

We have also used netstat to determine the cuplrit of our conflict. 

It seems that NIPXISM and other NI apps/services may choose different ports on startup.  This makes the problem intermittent, which made it hard to track down.

The conflicting port is on a customer device (embedded software on a unit), so it would be difficult to ask them to change.

Is there a list of ports that your apps use?  If we have to ask our customer to change, it would be helpful to have a list of ports to avoid.

[Wild_man]

Dave,

I don't believe that we have a published list of ports used within the application, only the ports that actually communicate over the network and require firewall configuration.

Could you provide a little more information about your application? Are you working with a PXI system such that NIPXISM is a necessary service or would it be possible to disable it to prevent it from utilizing ports you need for other purposes?

[TucsonDave]

Yes, we have a PXI system, therefore it doesn't seem like I can disable the service.

It appears that I need to go back to my customer and tell him that he needs to change his port.  However, I need to give him a safe port he can use.  It would really help if I had some idea of what ports NI's applications use.  I can infer some of the ports from my netstat logs, but I do not want to trip across another conflict later.

Can you provide me a list of the ports that your applications may use?  Is it possible to configure the apps to use other ports?

[Wild_man]

As a note, I have also found the ports to change after a reboot of my system. There still appears to be 9 ports in total.

[Wild_man]

I spoke with a Product Support Engineer who verified with one of the developers that our software makes no specific request for port 41985, rather we are just using the Windows (Winsock) API to give us ports. 

If you can reserve this port before our software then there should be no conflict, either by starting your program before nipxism.exe on startup or by programatically stopping the service, reserving the port, and restarting the service.

It also looks as though it may be possible to reserve a port or range of ports for your other application using the Windows API although I am not familiar with this.

https://msdn.microsoft.com/en-us/library/windows/desktop/gg696068(v=vs.85).aspx

[Wild_man · Accepted solution]

You may also be able to limit the range of the computer's dynamic ports such that the computer cannot assign port 41985 as a random port. It looks as though 41985 is inside the default Windows dynamic port range, which also gives you an answer about what port numbers to avoid if you choose to modify the third party device.

https://support.microsoft.com/en-us/kb/929851

[TucsonDave]

Unfortunately, the nature of our system will not allow us to start the app before the service (long story).

I think we can use one of the suggestions you have made.  In fact, I think it would help us manage our systems better.

Thanks for your help and suggestions.

[TucsonDave]

SUMMARY:

Let me try to summarize for others who may encounter the same or similar problem.

NI has many services that may run on a system.  Some of these services connect to servers.  While the server may have a fixed port, the client often does not.  In those cases,the operating system assigns a port from a range of values.  It is this range that is referred to by WildMan.  These ports are referred to as dynamic or ephemeral.  Most importantly, they are chosen at random from that range.  In my case, it randomly chose a port my customer wanted to use and we had a conflict.

You may change the range from which the OS chooses a dynamic port.  WildMan supplied links to articles that describe the command (netsh) to do this.  Note that the command does not make those ports completely unavailable: they are still available for general use, just not as dynamic ports.  Therefore, you can effectively protect yourself from conflicting with dynamic ports by using the command to narrow the range and choosing a port outside that range.