IPC has defined several types of via protection in the IPC-4761 standard. In order to specify which holes should be protected, a separate layer showing the holes to be filled should be added to the board. This layer may be imported as a separate Gerber file, or it may be generated from the existing drill file(s).
If your CAD system has generated a Gerber file with the via holes to be protected or press fit, link that file to the Tented vias, Plugged vias, Filled vias, Capped vias or Press-fit holes layer in the Additional layers submenu.
If you do not have such a Gerber file available, a via protection or press-fit layer may be created by specifying the via protection for one or more tools in a drill file. This is done by right-clicking on a tool in the Drill tools pane and choosing press-fit or the desired type of via protection.
To remove via protection from a tool, right-click on the tool and choose Remove via protection.
The About via protection menu item opens a web page with an explanation of the various via protection types.
Note: All tool diameters should be correctly defined prior to marking tools with via protection or press-fit.