How can I set up a floating license through a firewall?

Problem description: 

I have installed concurrent licenses of PLECS on my FlexNet license server. As long as I'm connected directly to the server I can check out licenses from client computers using the the following file 'network.lic':

SERVER <licenseserver> ANY

However, if I am behind the firewall, I cannot check out any license.


The communication with the license server requires two TCP ports. For a firewall configuration, both ports need to be explicitly assigned in the license file so they can be opened on the firewall; the server port number (port1) is specified on the server line of the license file, and the return port (port2) on the vendor daemon line.

The server license file 'plexim.lic' syntax is:

SERVER <licenseserver> <hostid> <port1>
VENDOR plexim PORT=<port2>

The corresponding client license file 'network.lic' would look like this:

SERVER <licenseserver> ANY <port1>