Alphatronics, Inc.
Virtual Port Monitor 6.0
Automating print to file for over 20 years!
Now with TCP/IP printing, SNMP, IPP, MDNS, and application debug reporting.

Virtual Port Monitor acts as a multi-port print stream capture service. It can receive data using the most popular methods, and place the captured stream into the output folder you select.

Initially developed exclusively as a Windows printer port monitor, it has evolved to also include TCP/IP Socket, IPP, and AirPrint as endpoint options, as well as leveraging MDNS, DNS-SD, and SNMP for network discovery and configuration, enabling BYOD / driverless printing from Windows, Mac, iOS, Android, and Linux platforms.

Once the file has been written the the output folder, an executable, script, or batch program can be run with the name of the file automatically added to the end of the command line or at the position of %1. Other generated environment variables are also available for insertion into the command line.

The new Debug Reporting feature can be enabled to provide screen shots, Standard Output / Error messages, as well as security and environment information. Debug Reporting can be enabled per-port as either always enabled, disabled, or triggered upon error detection.

Dashboard screen shots:
Port dialog screen shots:
Key Features:
Platforms Supported:
What's New:


View and control the status of Virtual Port Monitor using a single application.

TCP/IP Printing

Capture printer output from network clients or loopback using a Standard TCP/IP Printer Port.

This allows the capture of Version 4 printer driver data as well.

IPP (Internet Printing Protocol)

Capture printer output from clients using Internet Printing Protocol, which is used by most portable devices.

SNMP (Simple Network Management Protocol)

Enables network clients to associate a printer port with a printer driver when using the Add Printer Wizard. Macintosh devices utilize SNMP for printer status when using TCP/IP Printer ports.

MDNS (Multicast Domain Name System)

Enables certain network clients to discover the network printing services of Virtual Port Monitor.

Apple AirPrint

Advertises IPP Printers to iOS clients, such as iPhones and iPads.

Raster Utility

Converts AirPrint raster streams to print, document, or image formats.


Simplifies the command line by using preconfigured applications for post-processing.

Debug Reporting

Per-port debug reporting can be enabled, disabled, or set to emit a report on detected error.

When enabled, it provides a detailed report of the execution environment, taking the guesswork out of troubleshooting.

Resizable dialogs

Resizing the Port Dialog and the Dashboard resizes the objects on the screen.

Dialog state

Dialogs now remember their size, position, and menu page.

Configuration information is now stored in a standard SQLite database

No more issues with backup, restore, deployment, and replication.

Simply make a copy of the files located in the "%ProgramData%\Alphatronics\Virtual Port Monitor" folder.

UTC or local time for timestamped filenames.

Use the option you prefer.


Internally, the Dashboard application and Port Dialog use JSON/Ajax for communications with the Alphatronics Virtual Port Monitor service.

Previous versions used SOAP.

Windows RPC thread isolation

Virtual Port Monitor no longer changes the impersonation token of the Windows RPC threads used during port configuration.

A separate isolation thread is used on both ends of the conversation.

  • Build 15 [2019-10-14]
    • Initial Release for version 6.0.
  • Build 16 [2019-10-16]
    • Fixed a display issue with the Debug Report command line.
  • Build 17 [2019-11-07]
    • Fixed an issue with the installer detecting the currently installed version.
    • Other minor fixes.
  • Build 18 [2019-11-14]
    • Fixed an issue with TCP/IP Print Server startup and an issue with recovering from sleep mode.
    • New installations would fail to set the SNMP extension handler if the SNMP service is installed.
  • Build 19 [2019-11-22]
    • Fixed an issue with the built-in SNMP responder when 2 network paths exist for the same network (Ethernet and WiFi, for example).
    • Fixed the Color PS printer driver hardware ID.
    • Added additional drivers to the list of available SNMP printers from the DriverStore folder.
  • Build 20 [2019-11-24]
    • Fixed an issue in the port monitor DLL where newer Windows builds call ClosePort/OpenPort multiple times in the same session.
  • Build 21 [2019-12-23]
    • Fixed a buffer overrun issue when calling LookupAccountName.
  • Build 22 [2020-02-13]
    • Fixed an issue with recovery from sleep mode and resuming from a paused state.
    • Added improvements to the Dashboard application for refreshing status and resuming the service from a paused state.
  • Build 23 [2020-02-17]
    • Fixed an issue in the Dashboard application with detecting the currently installed version in locales that use the comma as the decimal separator.
  • Build 24 [2020-02-21]
    • Fixed an issue with re-initializing TCP/IP Printing after port configuration.
    • Fixed an issue with the dialog displaying selected individual TCP/IP bindings.
  • Build 25 [2020-04-10]
    • Added MDNS functionality.
    • Added Printer-MIB functionality to the SNMP Responder, which is used by MacOS clients.
    • Fixed an issue with SNMP Get-Next requests. "Walking" the MIB array when in stand-alone mode now works properly.
    • Fixed an issue with SNMP re-initialization when individual bindings are selected.
    • Eliminated temporary IPv6 addresses from the TCP/IP Printing bindings selection list.
    • Fixed a memory leak that occurred in the service when the SNMP printer list was populated.
    • Other minor improvements.
  • Build 26 [2020-05-05]
    • Eliminated unnecessary items the TXT record for MDNS pdl_datastream.
    • Fixed a memory leak in the MDNS responder.
    • Fixed a syntax error in the printer driver.
  • Build 27 [2020-05-07]
    • Fixed Printer Forwarding.
  • Build 28 [2020-07-14]
    • Added IPP.
    • Added AirPrint.
    • Added network change detection for DHCP lease renewal or network interface change or removal.
    • Refactored MDNS to announce, un-announce, and reduce replies by filtering out items identified in the answer section.
    • Fixed an issue with IPv6 address formatting.
    • Fixed a deadlock issue with the Dashboard application.
  • Build 29 [2020-08-13]
    • Fixed an issue where the service may fail to start due to a failed binary integrity check.
    • Other minor improvements.
  • Build 30 [2020-08-27]
    • Fixed an issue with MDNS and IGMP registration.
    • Fixed an issue with MDNS, IPP, and Android printing.
    • Other minor improvements.
  • Build 31 [2020-09-04]
    • Eliminated the print spooler requirement for DOS printer ports by redirecting directly to the Alphatronics service.
  • Build 32 [2020-09-08]
    • Fixed an issue where a crash would occur when the configuration dialog was closed when the help window is open.
    • Fixed an issue where DOS LPT port redirection would be cleared if the spooler closed the port.
    • Added a filter to eliminate network and direct printers from the printers list on the Forwarding page of the configuration dialog.
    • Restructured the configuration dialog to improve UI flow.
    • Updated the help file.
    • Other minor improvements.
  • Build 33 [2020-11-12]
    • Fixed an issue with a rare race condition occuring when the MDNS server was restarted.
    • Added a legacy printer list for printer selection.
    • Removed the PrintStress utility from the distribution. It can be downloaded from the "FTP Area".
    • Other minor improvements.
  • Build 33 installer update [2020-12-09]
    • Updated the installer to fix an issue with Windows 7 and Server 2008 R2 freezing at startup. These versions require security patch kb2533623 to be installed.
  • Build 34 [2020-12-23]
    • Downgraded the installer to work with Windows XP, Server 2003, and Server 2008. As a result, the aforementioned security patch is no longer required.
    • Added support for Windows XP, Server 2003, and Server 2008.
    • Fixed an issue with loading / creating the user profile when a security context is specified.
    • Fixed an issue where selecting the post-print application using the browse button would erase the first paramter of the command line.
    • Added a feature to the browse for application dialog, to select the current application in the tree view.
    • Added a feature to the browse for directory dialog, to select the current output directory in the tree view.
    • Updated the Output Folder link in the dashboard application to open an existing explorer window if available.
  • Build 35 [2021-03-17]
    • Added Raster Utility to the distribution.
    • Add Launcher to the distribution.
    • Updated the IPP server and DNS-SD TXT records to further support the URF raster format.
    • Added an option to override the output file extension based on IPP MIME type.
    • Improved the debug report to include all top-level windows in screen capture images.
    • Added an offline registration option for systems that are not connected to the internet.
    • Other minor improvements.
  • Build 36 [2021-03-19]
    • Fixed an issue introduced in build 35 with storing and retrieving user credentials.
Try before you buy!
The 30 day free trial enables you to test the functionality and speed of the product before purchase.
Version 6.0 is not considered a minor upgrade, therefore version 4 and 5.0 registration codes will not work with version 6.0 software.
Software Terms and Conditions
Questions and Answers Page
Developer Kits
Sample Debug Report
Which license is right for you?
All purchases of Virtual Port Monitor Include a complimentary copy of PrintFiler. PrintFiler makes it easy to copy your printer output files to any printer installed on your computer. The complimentary license is of the same type for PrintFiler as the Virtual Port Monitor license purchased.
Upgrading from version 5.0? Receive a one-time 15% discount for any edition by entering your version 5.0 serial number here and applying it at the time of purchase.
Single User License (Volume discounts available)
$145.00 USD
Site License (Volume discounts available)
$345.00 USD
Enterprise License
$4140.00 USD
Prices are subject to change without notice. All sales are final.