UPDD TCP IP port utilisation
UPDD utilizes TCP/IP for inter-process communication. The user mode driver component (tbupddwu) listens on port 4141 and other programs (including custom programs utilizing the UPDD API) communicate with this port. The driver requires access to TCP/IP port 4141 for internal computer processing only. This is bound to the loopback adapter only, i.e. it is available only to processes running on the local machine.
With UPDD version pre 4.1.10 and depending on your system configuration, particularly firewall settings, you may be asked to accept incoming connections when you install the driver. It may also be desirable to disable logging of this port to avoid recurring firewall messages.
However, starting with UPDD version 4.1.10 this port can be bound either to the local loopback address only, or all addresses. In most cases the default option (local loopback) is used and there should be no firewall issues. In a rare case that a firewall program reports an issue in this configuration if can be safely accepted as only local processes can open this port.
When specialist UPDD I/P features are to be used (to provide distributed touch facilities) then all addresses are bound, allowing the port to be opened from any network node with the appropriate access and this access should be managed using firewall rules. Binding to all addresses is enabled by setting the updd option:
If local processes are blocked from accessing this port then a UPDD API based program cannot communicate with the driver.
Most importantly you would not be able to calibrate.
The behaviour in the event that port 4141 cannot be opened for incoming connections is that the connection will be retried 120 times and then the driver will load and work normally, apart from not being able to accept API connections.