Comment # 6 on bug 795791 from Stakanov Schufter

this is still the case with a fresh install of 13.2. The only thing that can
stop listening X on 6001 when you have a multiuser system is to set "- nolisten
tcp" as an argument in /usr/share/kde4/config/kdm/kdmrc as is:
# Additional arguments for the X-servers for local sessions.
# This string is subject to word splitting.
# Default is ""
ServerArgsLocal=-nolisten tcp
if you do this, it stops. If not, the settings in yast and the settings for kdm
are there but simply not honoured.