[Tex/LaTex] geometry sets footskip too small

Question

I'm using the geometry package to change the header and footer of my page to specific values. Until now, it wasn't possible for me to get the footer in the right dimensions. The header looks has its 17mm, but the footer doesn't. Here is a minimal example which I compile with LuaLaTeX.

\documentclass[paper = a4]{scrartcl} 
\usepackage{blindtext, fontspec}
\usepackage[automark, headsepline, footsepline, plainheadsepline, plainfootsepline]{scrpage2}
\pagestyle{scrheadings}
\usepackage[  includeheadfoot
            , headheight = 17mm
            , footskip = 17mm
            , tmargin = 0mm
            , bmargin = 0mm
            , verbose
           ]{geometry}

\begin{document}
\Blinddocument
\end{document}

Do you have an idea, how to get a footer with 17 mm, too?

Answer 1

You want that the distance of the footline separator from the bottom is 17mm. Thus you have to do the computation in a different way:

\documentclass[paper = a4]{scrartcl}
\usepackage{blindtext,fontspec}
\usepackage[automark, headsepline, footsepline,
  plainheadsepline, plainfootsepline]{scrpage2}
\pagestyle{scrheadings}

\normalfont\normalsize
\usepackage[
  includehead,
  headheight = 17mm,
  footskip = \dimexpr\headsep+\ht\strutbox\relax,
  tmargin = 0mm,
  bmargin = \dimexpr17mm+2\ht\strutbox\relax,
]{geometry}

\begin{document}
\Blinddocument
\end{document}