Basically, you need to install the License Manager, and send the almhostid of the machine to keys@scitools.com.

We will send you back a license.dat file to install, and then you start the license server service/daemon.

If you would like more information on tracking licenses or releasing an Understand license, please see the Licensing section on our Support Page.

Choose Your Host

The license server can be any Linux, Mac OSX, or Windows(Vista or newer) system which is accessible from the client that will be running Understand software. You can mix and match operating systems, for example you can run a client on Windows and use a Linux system as the license server. The license server software is extemely light weight and only uses a few Mb or RAM when running, so it can be hosted on a workstation or Virtual Machine without any issues.

Download Floating License Manager

Download the latest License Manager package from https://scitools.com/download/licensemanager/

Each Understand installation kit also contains the needed license manager software. So if you intend to also run Understand on the server install the full Understand package instead of the above package.

Install license server

Windows Install

Run the installer.

Linux Install

To install, extract the kit in the location that you want it. The SciTools directory will be created automatically.

tar -xvzf LicenseManager-4.0.853-Linux-x86.tgz

NOTE: It is CRITICAL that the license kit be extracted in a manner that retains its original directory structure. Once extracted the SciTools directory containing the tools can be moved around, but the entire structure must be moved together.

Mac Install

Drag the Understand App bundle into the Application folder


Determine the Almhostid of the server

The almhostid is a unique identifier that allows us to identify your machine in our licensing database. It is in this form:


Where the first eight characters are the unique identifier and the machine name is after the slash. We need that almhostid to generate the custom license file for that machine.

Windows/Linux GUI Install

Find and run licenseserver. It is located in c:\Program Files\SciTools\bin\pc-win64\


Choose one of the options under the AlmHostId section to view the Almhostid

Windows/Linux Command Line Install

Open a Command/Terminal Window and run:


Mac Install

Open Terminal and run the following commands:

cd /Applications/Understand.app/Contents/MacOS

Request License File

Email the complete AlmHostId  to keys@scitools.com. Once we have this information we will send you a license.dat file for your system.

If the request is made during our working hours (8 – 5 MST), you should get the file back within one hour (usually much quicker).

Install the license file

Windows/Linux Install

Place the license.dat file that we send back into the <InstallDir>/SciTools/conf/license/ subdirectory. Verify that UDP port 9000 is open on the server.

Mac Install

Save the license file to /Applications/Understand.app/Contents/Resources/conf/license/license.dat. Verify that UDP port 9000 is open on the server

Start the license server

Windows/Linux GUI


In the License Server dialog, Browse to the location of the license.dat file. The file MUST be in the same location as the Licensing window shows.

Select “Start” in the upper right.


The Server Status should show that it is running.


If you minimize or close this application it will shrink to a small magnifying glass icon in the system tray.

Windows Command Line Install

Run almdNTconfig with the -c option to install and start the license manager as a Windows service. Use the -l option to specify the location of the license file.

almdNTconfig -c -l "c:\program files\SciTools\conf\license\license.dat"

To see other options use almdNTconfig -h

Linux Command Line Install

Run almd to start the license server daemon, and specify the location of the license file with the -l option.

./almd -l /usr/bin/scitools/conf/license/license.dat

To see other options use almd -h

In order for the License Server to start after a reboot of the machine, you will need to add licenseserver to your Start Up. The instructions for this may vary for each Linux distribution.

Mac Install

Run almd to start the license server daemon, and specify the location of the license file with the -l option.

./almd -l /Applications/Understand.app/Contents/Resources/conf/license/license.dat

A script can be used to start the License Server after a reboot of the machine.
Create a file called: com.scitools.almd.plist in /Library/LaunchDaemons with these contents:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN"
<plist version="1.0">

Replace /path/to/SciTools/bin/macosx/almd and /path/to/license.dat with the actual paths to where the daemon and license.dat are installed. Now the daemon should start at boot.

Verify the License Server Is Running

The Almstatus command will show the current state of the license server, whether or not it is running, and how many licenses are being served.

Windows GUI Install

Click the “View Status” link in the upper right corner.

Windows Command Line Install

almstatus -l "c:\program files\SciTools\conf\license\license.dat"

Linux Command Line Install

./almstatus -l /usr/bin/scitools/conf/license/license.dat

Mac Install

./almstatus -l /Applications/Understand.app/Contents/Resources/conf/license/license.dat

Test with a client app (optional)

As long as the license server is running, you will be able to run Understand from another client. When Understand prompts for a server name, either the IP address, or the name of the server that the License Manager is running on will work.

If you want to check on the license server status from a client machine, run almstatus from the command line. It will show how many licenses are available and who has licenses checked out.


Below are some of the most common problems encountered when hosting a license server.

Unsupported Operating System

The license server can be any Linux, Mac OSX, or Windows(Vista or newer) system which is accessible from the client that will be running Understand software. Windows XP and Windows Server 2003 are no longer supported. You can mix and match operating systems, for example you can run a client on Windows and use a Linux system as the license server.

Older Versions

Understand 4.0 requires that the license server be upgraded to at least build 772. You can see the license server build number in the upper left section of the GUI or from the command line by running almd -h You can get the latest version from https://scitools.com/floating/

You will also need an updated license file, you can tell the newer license files because they have a “maintenance” column with the date that the maintenance expires. You can get an updated license file from keys@scitools.com as long as your maintenance is up to date.

Firewall Ports

Understand uses UDP port 9000 to communicate with the License Server. If there are problems, ensure that this port is open on both the client and server.

Almhostid Changed

The license file is built targeting the Almhostid of the specific server. If a hardware change causes the almhostid to change, a new license will need to be generated. Send the new almhostid to keys@scitools.com and we will rebuild the license file.

DNS Resolution Problems

Sometimes the client where Understand is installed has problems finding the server. Verify that you can ping the server, or trying specifying the IP address instead of name of the server in both the license file and in the client.

Service Won’t Start

Sometimes some servers are setup in such a manner that users cannot create services from the command line. This seems to happen mostly on Windows Server 2008. The license manager may appear to start, but a check in the services list does not show the “SciTools License Manager” Service. The work around for this is to create a scheduled task to launch the License Manager at machine startup instead of using services. More details here (https://scitools.com/support/windows_no_service/)

Delete Licenses on Client

Sometimes the client can hold on to an invalid license. In the client, try hitting the “Delete All Licenses” button in the licensing dialog, and then re-entering the name of the license server.

Still Not Working?

If none of those options are successful the next step is to simulate a connection and send us the log files.

Server Logging Setup

On the server side run this command to setup the logging:
almd -d 3 -f path/to/serverlog.txt -l path/to/license.dat

Client Logging Setup

On the client side first create a file with the server connection information in the Understand Installation folder (i.e. SciTools\conf\license\license.dat)
It needs to have this line in it (replacing ServerIP with the actual IP address of the license server)
Server: ServerIP 00000000 8998

Next run this command from the command line to simulate a connection to the license server.
almtest -d 3 -f path/to/clientlog.txt

Then send the serverlog.txt and clientlog.txt files to support@scitools.com

Hopefully analyzing the communication between the two will help us determine what is wrong.