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Documentation / Mathematica / Getting Started / Network SysAdmin Guide / The Mathematica License Manager /

5.6 Troubleshooting with MathLM

The machine that you choose as a license server should have the following features.

  • The machine should be stable and have a reliable TCP connection to the clients you want to serve. This is important because if the license server crashes, the serving of licenses to all client machines on the network will be disrupted.

  • The license server does not need to have Mathematica installed on it. Although a MathLM license server can also serve as its own client, this is not recommended. By having a dedicated license server, you can ensure that there are not too many demands on its resources.

  • Ideally, there should not be any intervening firewalls between the license server and the clients. If there is an intervening firewall, you will need to configure the network to allow traffic to an appropriate port through the firewall.

The following errors can arise when running Mathematica with a network license.

The client cannot connect to the license server when Mathematica is first launched.

If this happens, the following dialog box appears to notify you of an error.

You can choose one of three options:

Enter Password—brings up the front end password dialog box.

Quit—exits Mathematica. You are given the option of saving your work.

Retry server—attempts to reconnect to the server.

The client can connect to the license server but is denied a license because the process limit has been reached.

If this happens, the following dialog box appears to notify you of an error.

You can choose one of three options:

Enter Password—brings up the front end password dialog box.

Quit—exits Mathematica. You are given the option of saving your work.

Retry server—attempts to reconnect to the server.

The connection to the license server is lost after the client is connected to it.

Once Mathematica is running, the client contacts the license server every two minutes to refresh its license. If three successive attempts to contact the license server are unsuccessful, a dialog box will appear informing you that the license server could not be contacted. This happens six to eight minutes after the connection to the license server is lost.

If you are running the front end, the following dialog box appears.

You can choose one of three options:

Enter Password—brings up the front end password dialog box.

Quit—exits Mathematica. You are given the option of saving your work.

Retry server—attempts to reconnect to the server.

If you are running the kernel only, you will receive the following prompt to indicate that the connection has been lost.

Lost connection to server>

You may attempt to connect to the license server again, or you may exit Mathematica.

Your options are:

    retry (or r) to retry server

    exit (or quit) to exit Mathematica

If mathlm quits it will have to be restarted. If more than eight minutes have elapsed since it quit, you must also restart all copies of Mathematica on client machines connected to that license server.

Using the option -verbose, you can start mathlm and have information sent to a terminal in real time to see how requests are handled by mathlm. This can be very useful when debugging problems with machines on the network that cannot connect to the license server.