Chapter 5. Printer Features
be able to use printers based on the location of their terminals, when the Printer Access Control
feature is enabled.
5.5.1. Theory of Operation
Each time a user requests a new session or reconnects to an existing session, the hardware (MAC)
address of the terminal is sent along with the request from the ThinLinc client. Using the same database
as the nearest printer feature used to find which printer is closest to the user, the printer access control
feature calculates which printers the user is allowed to use, and then configures the access control of the
printing system (CUPS).
This way, the user is presented with a list of printers that only contains the printers relevant for the
location where the terminal the user is currently using is located. In a situation where a user has multiple
sessions running from multiple clients, all printers associated with the different terminals will be made
available.
5.5.2. Requirements
• CUPS v1.2 or higher.
5.5.3. Activating the Printer Access Control Feature
First, make sure you have configured the printers in your ThinLinc cluster as documented in Section 5.2.
For the Printer Access Control Feature, a central CUPS daemon on the VSM Server host is required, and
all agent hosts must have a correctly configured /etc/cups/client.conf.
To activate the printer access feature, create two symlinks on the host running VSM Server, as follows:
ln -s /opt/thinlinc/sbin/tl-limit-printers /opt/thinlinc/etc/sessionstartup.d
ln -s /opt/thinlinc/sbin/tl-limit-printers /opt/thinlinc/etc/sessionreconnect.d
The first symlink makes sure tl-limit-printers is run when sessions are started. The second makes sure it
is run at reconnects to existing sessions. More details about the session startup can be found in Section
14.4.
Note: With the above configuration (symlinking tl-limit-printers into sessionstartup.d and
sessionreconnect.d), the client will not get an answer back from the server until
tl-limit-printers has finished its execution. This is the desired behaviour if it is strictly
neccessary that printer access rights are correct when the user connects to the session. In
environments where it is acceptable that the final list of printers shown to the user may not be
finished when the user connects to the session, place the execution of tl-limit-printers in the
background, as detailed in Section 14.4.1.1, as that will decrease the time the user has to wait for the
session to appear on his client.
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