jotowaty

This is what worked for me.

How do I install licenses (without internet access)?

If you do not have internet access from the machine running Houdini, you will need to use a second machine with internet access to acquire your licenses.

Start the Houdini License Administrator from the Start Menu if using Windows or from the Applications folder in Finder if using Mac. If using Linux, run hkey after sourcing the houdini environment (source houdini_setup or houdini_setup_bash if using the bash shell)
Click on the Server Information tab and record the license server host and the server code.
From the machine with internet access, go to https://www.sidefx.com/services/non-commercial-license/ [www.sidefx.com] . Enter the server name and server code and select the Houdini product to activate.
Cut and paste the SERVER and LICENSE keys and and save them to a file on a disk.
On the machine running Houdini, select File -> Manually Enter Keys…. Paste each key into a text box using Ctrl+V and press OK.
You can now run the Houdini product.
If installing licenses in local licensing mode, you may need to set the read-write permissions on the license directory (C:\Windows\keys or /usr/lib/sesi or /Library/Preferences/sesi/) so that the License Administrator utility can create the “licenses.local” file. Otherwise you may get grayed out fields in the License Administrator dialog box.