Server communication

Please find below in quick reference format details of client-server communication for GWB floating licenses. To see related topics, please see our Floating license installation page.

Server components

The components making up the server, and their functions are:

  • lmgrd.exe – The license manager daemon, which is responsible for connecting clients to the correct vendor daemon.
  • hydrokey.exe – GWB's vendor daemon, responsible for providing licensed features to clients and tracking how many licenses are in use.

Communication sequence

The communication between a client asking to check out a seat and the server responding to the request can be summarized:

  • client → LMGRD — Contact LMGRD at specified port, or at 27000-27010
  • client → LMGRD — Where is the vendor daemon for HYDROKEY?
  • LMGRD → client — HYDROKEY is at port@hostname
  • client → HYDROKEY — Request to check out a feature
  • HYDROKEY → client — Accept or decline request


Any firewall positioned between the clients and the server needs to allow lmgrd.exe and hydrokey.exe to communicate over TCP. Depending on the type of firewall, you need to allow either both applications or the ports assigned to them to traverse the firewall. If you allow by port, you should explicitly assign a port to each application (see Server ports).

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