HOWTO: Use an Externally Hosted License

Many software packages require a license.  These licenses are usually made available via a license server, which allows software to check out necessary licenses.  In this document external refers to a license server that is not hosted inside OSC.

If you have such a software license server set up using a license manager, such as FlexNet, this guide will instruct you on the necessary steps to connect to and use the licenses at OSC.

Users who wish to host their software licenses inside OSC should consult OSC Help.


You are responsible for ensuring you are following your software license terms.  Please ensure your terms allow you to use the license at OSC before beginning this process!


Broadly speaking, there are two different ways in which the external license server's network may be configured.  These differ by whether the license server is directly externally reachable or if it sits behind a private internal network with a port forwarding firewall.  

If your license server sits behind a private internal network with a port forwarding firewall you will need to take additional steps to allow the connection from our systems to the license server to be properly routed. 

License Server is Directly Externally Reachable

Figure depicting a License Server with firewall connected to the internet, and an outbound compute node whose traffic is routed through NAT to the internet

License Server is Behind Port Forwarding Firewall

Figure depicting a License Server with a Full Port Forwarding Firefall inside a Private Internal Nework connected to the internet, and an outbound compute node whose traffic is routed through NAT to the internet


If you are unsure about which category your situation falls under contact your local IT administrator.

Configure Remote Firewall

 OSC changed NAT IP addresses on December 14, 2021. Please update the IP addresses of license server configured for the firewall to allow the connections from ( to 

In order for connections from OSC to reach the license server, the license server's firewall will need to be configured.  All outbound network traffic from all of OSC's compute nodes are routed through a network address translation host (NAT).

The license server should be configured to allow connections from including the following IP addresses to the SERVER:PORT where the license server is running:


A typical FlexNet-based license server uses two ports: one is server port and the other is daemon port, and the firewall should be configured for the both ports. A typical license file looks, for example,

SERVER 0050XXXXX5C 28000
VENDOR {license name} port=28001

In this example, "28000" is the server port, and "28001" is the daemon port. The daemon port is not mandatory if you use it on a local network, however it becomes necessary if you want to use it outside of your local network. So, please make sure you declared the daemon port in the license file and configured the firewall for the port.

Confirm Configuration

The firewall settings should be verified by attempting to connect to the license server from the compute environment using telenet.

Get on to a compute node by requesting a short, small, interactive job and test the connection using telenet:

telnet <License Server IP Address> <Port#>

(Recommended) Restrict Access to IPs/Usernames

It is also recommended to restrict accessibility using the remote license server's access control mechanisms, such as limiting access to particular usernames in the options.dat file used with FlexNet-based license servers.

For FlexNet tools, you can add the following line to your options.dat file, one for each user.


If you have a large number of users to give access to you may want to define a group using GROUP within the options.dat file and give access to that whole group using INCLUDEALL GROUP <group name> .

Users who use other license managers should consult the license manager's documentation.

Modify Job Environment to Point at License Server

The software must now be told to contact the license server for it's licenses.  The exact method of doing so can vary between each software package, but most use an environment variable that specifies the license server IP address and port number to use.

For example LS DYNA uses the environment variable LSTC_LICENSE and LSTC_LICENSE_SERVER to know where to look for the license.  The following lines would be added to a job script to tell LS-DYNA to use licenses from port 2345 on server, if you use bash:

export LSTC_LICENSE=network

or, if you use csh:

setenv LSTC_LICENSE network

License Server is Behind Port Forwarding Firewall

If the license server is behind a port forwarding firewall, and has a different IP address from the IP address of the firewall, additional steps must be taken to allow connections to be properly routed within the license server's internal network.  

  1. Use the license server's fully qualified domain name in SERVER line in the license file instead of the IP address.
  2. Contact your IT team to have the firewall IP address mapped to the fully qualified domain name.


Software Specific Details

The following outlines details particular to a specific software package.  


Uses the following environment variables:


If your license server is behind a port forwarding firewall and you cannot use a fully qualified domain name in the license file, you can add ANSYSLI_EXTERNAL_IP={external IP address} to ansyslmd.ini on the license server.