# Advanced topics

## Hardware address reporting

When the client connects to a server, it reports its hardware address. On Linux, the active interface with the smallest MAC address is used. On Windows, the address of the first interface (as listed in the Control Panel) is used.

## Client update notifications

The client includes a feature which can periodically check for new versions. This functionality is affected by the configuration parameters `UPDATE_ENABLED`, `UPDATE_INTERVAL`, `UPDATE_LASTCHECK`, `UPDATE_MANDATORY`, and, `UPDATE_URL`. These are described in Client configuration parameters. During an update check, the client retrieves the file specified by `UPDATE_URL`. An example follows:

    WINDOWSINSTALLER = https://www.cendio.com/downloads/clients/tl-latest-client-windows.exe
    LINUXINSTALLER = https://www.cendio.com/downloads/clients/thinlinc-client-latest.i686.rpm
    DEFAULTINSTALLER = https://www.cendio.com/thinlinc/download
    OKVERSIONS = 3.2.0 3.3.0

The `OKVERSIONS` parameter specifies a list of valid client versions. If the running client version is different, the client will notify the user. The `WINDOWSINSTALLER`, `LINUXINSTALLER`, and `DEFAULTINSTALLER` parameters specifies the updated client packages for Windows, Linux, and other platforms, respectively.

## Adding custom branding to the login window

It is possible to add a custom logo to the main ThinLinc client window, making it easily distinguishable from a generic client. The custom logo will be placed to the right of the input fields.

Adding the logo is easy. The new logo must be a PNG file with maximum width and height of 50 pixels. On Windows, just add the file `branding.png` in the same directory as the executable with the custom logo. On Linux, the file name is `/opt/thinlinc/lib/tlclient/branding.png`.

For custom branding of the Web Access login page, see Custom branding.

## XDM mode (Linux only)

When installing dedicated clients, for example old PCs or thin terminal boxes, it’s common to install the client to run in XDM mode. XDM is an acronym for X Display Manager and is the name of a small graphical program used for graphical logins in many Linux systems. By using the ThinLinc client in XDM mode you can make sure that the client appears automatically when the client hardware is started and that it reappears directly after a user logs out.

To run the client in XDM mode you need to start it with the `-x` option. When running in XDM mode the following changes will be made to the client interface.

- The Exit button is removed.

- Always use full screen on all monitors.