Using VPN to get license from License Server

Technical Note 88251



9/7/2015 4:17 PM


There is no license fetched over the VPN connection.

Applies to

This Technical Note applies to IAR System products that uses License Management System version 2 (LMS2).


  • IAR doesn't support the VPN connection itself, that is, when it comes to problems using/setting up VPN involve the IT Department and/or the VPN provider.
  • Present versions will accept VPN connections.
  • Please note that fetching a licenses over VPN must comply to the terms in the Software License Agreement for IAR Embedded Workbench.
  • Older versions of IAR products (using License Management System version 1 (LMS1)) will NOT accept to fetch a license using VPN connections.

Possible actions

Having all the above said, it is still possible to give some generic suggestions on troubleshooting:

  • Check that the port UDP 5093 is open all the way from the Client Computer through VPN, firewall(s), router(s) etc. to the License Server Computer. 
  • Ask the VPN expert at the IT department to examine size of the VPN packets - IAR Systems has seen cases where the VPN packet, that reaches the Client Computer is truncated, and thus the license isn't valid.
    • The VPN expert can try to reduce the MTU size on the server.
    • An MTU size of 1359 (on the server computer) made one VPN connection to work.
    • The VPN expert can try to make an VPN-rule to "enable fragmented packages"...
    • ...and also make a Firewall-rule to "enable fragmented packages".
  • If the VPN connection can't be established - Then you may consider the use of a commuting license. Details in:
  • <installation directory>\common\doc\
    Checking out a product for commuter authorization

Applies to versions

This Technical Note applies if using one of the following product(s), with the mentioned versions (or later).

Product Version Product Version Product Version Product Version
8051 8.11 V850 3.81 RL78 1.20 RX 2.40
430 5.51 R32C 1.40 78K 4.80 ARM 6.50
AVR 6.20 STM8 1.40 RH850 1.10 CR16C 3.20
M16C 3.60 AVR32 4.20 SH 2.30 visualSTATE 7.2
HCS12 4.10            

All product names are trademarks or registered trademarks of their respective owners.

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