The following information is from http://www.xilinx.com/tools/faq.htm.
Before using the daemon process of floating license, make sure to kill the existing one on the server.
How can I start a Floating License Server?
To start the license server system invoke the license server manager (lmgrd) on the server machine.
Certificate-based Servers: "lmgrd -c <filename.lic>" for a single license file or "lmgrd -c- <Directory name> to have lmgrd processes all files with the .lic extension in the license-directory and start all vendor daemons referred to in those files.
Activation–based Servers: If you are starting a license server system for an activation-based server license, the trusted storage area containing the license authorization must be on the same machine running the lmgrd executable. With activation licenses, the "lmgrd -c " command will cause the executable to automatically look in the server's trusted storage area and serve all license authorizations found there.
In the case where both a Xilinx certificate based license and an activation-based license are going to be served from the same license server, lmgrd will use the host name, daemon and port specified in the license file (.lic) for both the Xilinx licenses in the file and the Xilinx licenses in the server's trusted storage area.
If there are no Xilinx licenses that will be served, a basic server .lic file is still required in order to define the host name, port and Xilinx daemon so that the licenses in the server's trusted storage area may be served.
To create a basic license file:
From a command shell containing a path to the Xilinx server tools run lmutil lmhostid Choose one of the host id's produced by the previous command and create a file, perhaps called "Xilinx_Server.lic", which contains the following text: SERVER <host_name> <host_id> <port>
USE_SERVER
VENDOR xilinxd
For port number, Xilinx's default is 2100, although any unique port number may be used. The command to serve the activation licenses in this example, would be:
lmgrd –c Xilinx_Server.lic
The –l switch can be used when invoking lmgrd to specify a log file to record license daemon status and actions (e.g. "lmgrd -c /usrfiles/licenses/server1.lic –l /usrfiles/licenses/startup/my_log.txt").
For clients to point to a Floating License key either the XILINXD_LICENSE_FILE variable (preferred) or the LM_LICENSE_FILE variable must point to the port@server location.
Run the Xilinx License Configuration Manager (XLCM)or Vivado License Manager (VLM).
From the "Acquire a License" screen of the XLCM, click on the "Manage Xilinx Licenses" tab. From VLM, choose the "License Search Locations" screen from the list on the left.
On the Manage Xilinx Licenses_tab,or "License Search Locations" screen, enter the network path to the license server in the port@server format into the XILINXD_LICENSE_FILE field and press the Set button next to it. The default Xilinx port number is 2100.
Note: For Linux operating systems, licensing environment variables cannot be set using the Xilinx License Configuration Manager (XLCM). The environment variable fields are read only, therefore they are grayed out and there are no "Set" buttons. The environment variable must be set using the appropriate shell and commands.