You can define your license servers by defining the path to one or more license files. However, this method is limited by architecture because the UNIX and Windows NT/2000 license files are a bit different. These differences cannot be reconciled functionally by a license manager of an opposing architecture.
See Also: How are Unix and NT license files different?
When defining one or more license files using the ESRI_LICENSE_FILE variable, you can state the absolute paths, the variable paths (UNIX only), or both.