Promotic

PROMOTIC system and Windows remote desktop (RDP)

This chapter describes the usage of the PROMOTIC system via the Windows remote desktop (by means the RDP protocol).
The Windows remote desktop allows to display the Windows desktop on remote computer.
This approach is suitable for both short term remote access and permanent operation of the remote computer.

The Windows remote desktop can be used for displaying the desktop of remote physical computer or remote desktop of a virtual Windows computer.

There are multiple ways of achieving that. Most commonly, the instruments integrated in Windows OS are being used.
The client program using RDP protocol, allowing to access remote desktop is built in all Windows OS.
Also some Windows OS versions (e.g. server) allow to offer the Windows desktop to remote clients.

Windows Remote Desktop (RDP) support for various licence carriers:

1. netkey - Network licence key

Windows Remote Desktop (RDP protocol) works without limitations, see netkey - Network licence key. The number of running applications is monitored by the remote licence server PmLicServer.

2. swkey - Software licence key (.swk) bound to specific components of the Windows operating system

Windows Remote Desktop (RDP protocol) works without limitations, see swkey - Software licence key (.swk) bound to specific components of the Windows operating system. PROMOTIC has direct access to the licence on this carrier. The number of running applications is monitored locally directly by the PROMOTIC system.

3. hwkey - Hardware (USB) licence key

a) For new HW Keys distributed since 1.5.2022 and for the PROMOTIC system since version Pm9.0.21 Windows Remote Desktop (RDP protocol) works without limitations, see hwkey - Hardware (USB) licence key.
The PROMOTIC system has direct access to the licence on this carrier. The number of running applications in RDP mode is monitored locally directly by the PROMOTIC system.

Information about RDP support for a particular licence key can be found:
- in the INFO system of the application runtime - SYSTEM/Licence/Licence medium result (rdp:1)
- in PmManager - Licences/Available hardware keys (hwk=rdp:1;)
- in the application log file on the licence number line (hwk=rdp:1;)


b) For older HW Keys distributed before 1.5.2022 and/or for the PROMOTIC system older than version Pm9.0.21 Windows Remote Desktop (RDP protocol) does not work.
PROMOTIC does not have direct access to the licence on this carrier. The licence can be read by the local licence server PmLicServer.
In the RDP mode, the number of running applications is monitored by the local licence server.

The main problem connected with operation of the PROMOTIC system via Windows remote desktop by the RDP protocol is the limitation of permissions of the program launched in user mode by the remote user.
The PROMOTIC application launched this way does not have access to the HW Key (USB) and therefore cannot read its licence. PROMOTIC behaves as there is no licence key present in the USB port of the computer (physical or virtual).
On the other hand, a program running as service, launched by the Windows remote desktop (remote user session), can access the HW Key. This can be used in order to solve the licece access problem of the PROMOTIC system via the Windows remote desktop.

PmLicServer licence server (included in the PROMOTIC installation) is usually running as a service thus having access to the HW Key even in Windows remote desktop mode (RDP).
This is important because PmLicServer itself is protected by its HW Key and this protection is functional even in remote desktop session. PmLicServer provides network licences to PROMOTIC applications via the network protocols HTTP or HTTPS.
The applications can be located on the same computer (localhost) or on other computers in the network.

The practical solution for licencing PROMOTIC application that are managed or operated via Windows remote desktop (RDP) is to run the PmLicServer licence server on the same computer with the specific PROMOTIC application.
This way it is possible to overcome the limitation of the PROMOTIC application problem on Windows remote desktop while all necessary software and hardware components are concentrated on a single computer.

This is a standard solution of licencing local PROMOTIC application by PmLicServer that provides the application with a licence either on hwkey - Hardware (USB) licence key or netkey - Network licence key.
This is a recommended solution for Windows remote desktop (RDP) limited access to the HW Key (older keys).

This solution requires the computer (service) to have access to the HW Key (USB). If this is a virtual computer, then it is necessary to let it have access to the HW Key in USB permanently.
This can be achieved by software means (accesing the USB on physical HOST of the computer as USB in virtual GUEST computer) or by means of another hardware device that allows to operate virtual USB ports via Ethernet.

Accessing licences contained in the HW Key via the local licence server:
PmLicServer.ini:
Configuration file PmLicServer.ini - PmLicServer licence server
[Config]
Medium=none
Application ini file:
[Licence]
Medium=hwkey:k1234

History:
Pm9.00.21: HW Key works directly under Windows remote desktop (RDP), without the need to use a local licence server.
PROMOTIC 9.0.21 SCADA system documentation - MICROSYS, spol. s r.o.

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