(LMS1) Opening the communication port for license requests

Technical Note 29096






10/31/2019 1:51 PM

Note: - This applies to legacy versions of IAR Embedded Workbench (2013 and older) which used License Management System version 1 (LMS1).


This technical note gives you suggestions how to manually open the correct communication port for license requests.


Note that you cannot use PING for testing communication between Client and Server. The reason for that is that PING uses ICMP for communication.

The communication requirement is that UDP (User Datagram Protocol) port 5093 is open on:

  • the Server that runs the IAR License Server application
  • the Client PC
  • routers/bridges between subnets in the network

How you open UDP port 5093 depends on the kind of OS on the computer. It also depends on the application you use for administration of the routers/bridges.

Note that a restart might be mandatory for the change to be performed, that is, in some of the mentioned kinds of hardware. For example, the License Server typically needs to be restarted.


Port UDP 5093 must be open on the Client, the Server and between subnets. If problems persist you can contact IAR Systems support.

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