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Archived: Using Lookout, LabVIEW DSC and Network-Published Shared Variables with Firewalls

This document has been archived and is no longer updated by National Instruments

Hardware: PXI/CompactPCI>>Controllers

I have Windows firewall or another firewall hardware/software enabled on my computer. How can I use Lookout, the LabVIEW Datalogging and Supervisory Control (DSC) Module and network-published shared variables successfully?

The underlying foundation for NI networking is called Logos. The Shared Variable uses the National Instruments Publish-Subscribe-Protocol (NI-PSP), which is built on Logos. Similarly, communications between remote machines and between software and databases is based on Logos in Lookout 6.0.x and LabVIEW DSC 7.x and greater. In order for these technologies to work in conjunction with security-enhancing firewalls, some settings need to be adjusted from the default installation settings.

Prior to LabVIEW 8.5, these NI networking technologies used UDP communication. With the release of LabVIEW 8.5, the NI Variable Engine now supports a more efficient TCP-based implementation of the NI-PSP protocol.  Both the TCP-based (LabVIEW 8.5 and later) and UDP-based (LabVIEW versions prior to 8.5) versions of NI-PSP add layers such as error checking.  Firewalls often block some or all TCP and UDP ports.

If you are using LabVIEW 8.5 or later, please see Configuring Software and Hardware Firewalls to Support National Instruments Products as well as the LabVIEW Help.

If you are using a version of LabVIEW prior to 8.5, please determine the version of Logos in use on your machine:
  1. Navigate to WINDOWS\System32\lksock.dll.
  2. Right-click on the DLL and choose Properties.
  3. Determine the version of the DLL (steps will vary by version of Windows).
In all versions of Logos, UDP port 2343 is used for the directory service to allow NI software to determine which ports specific software components need to communicate on.

Logos 4.5 and previous
UDP ports for communication are assigned randomly in a range from 1024 up to the maximum of 65535. NI software will first connect to port 2343, ask which port the requested service is currently residing on and then find that port in the range of 1024 - 65535. Unblock UDP ports 1024 to 65535 to allow the software to work correctly.

Logos 4.6 and greater:
In these versions of Logos, ports are assigned incrementally rather than randomly. UDP port 2343 is still used for the directory service. Clients will attempt to connect to a given host at UDP port 5000. They will then increment upwards until they find an available port. Server ports will be used by each service (NI-PSP, LabVIEW DSC, or Lookout) running on your machine. These start at UDP port 6000, and increment upward until available ports are found. Open a minimum of 20 server and 20 client ports as a starting point along with UDP port 2343. If communication problems persist, open up more ports of each until the problems are resolved.

Related Links:
KnowledgeBase 3HUD6PUW: Configuring LabVIEW, LabVIEW DSC and Lookout to Work With the Windows Firewall
White Paper: Configuring Software and Hardware Firewalls to Support National Instruments Products
LabVIEW Help: Changing the Default Ports for TCP-Based NI-PSP (NI Linux Real-Time, Windows)


Report Date: 01/10/2006
Last Updated: 08/14/2014
Document ID: 3T9B75XL

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