Problem: Licenses are not released after closing an ArcGIS session
After closing an ArcGIS session, the license is not returned to the pool of available licenses. This is known as a hung license.
This is typically caused by inconsistencies or errors in network communication. Devices on the network such as switches, routers or firewalls that interfere with the communication between ArcGIS and the license manager, can also cause this problem.
Solution or Workaround
The license manager initiates two TCP connections to check a license in or out; one which defaults to TCP port 27005 (8.x and earlier) or 27004 (9.0 and later), and one on a random TCP port. This dynamic/random second port can be blocked by routers, switches, or firewalls on the network between the license server and the client. To alleviate this problem, set the license manager to run on a static second port, and then open this port on all intervening network devices.
Use a text editor to edit the license files to reflect the static second port. These files are located in C:\Program Files\ESRI\License directory for Windows and ArcGIS 8.x, and in C:\Program Files\ESRI\License\Arcgis9x for Windows and 9.x. They are in $ARCHOME/sysgen for UNIX. Add a PORT=#### to the VENDOR line in each .lic or .dat file as below:
VENDOR ESRI PORT=####
ArcGIS 9.x users will appear as follows:
VENDOR ARCGIS PORT=####
For Windows license managers, each of the *.lic files must be edited identically.