The documentation https://www.torproject.org/docs/tor-manual.html.en
says
that default value of CookieAuthentication is 0. However, until I set
it 0
in my torrc, tor wanted a cookie ("host 9051 515 Authentication failed:
Wrong length on authentication cookie.")
Hi TomÃÅ. The tor man page (and the documentation you cited) talks
about tor's defaults. However, since you're using Ubuntu you got this
from the deb, right? If so then the deb contains a torrc of its own
(which is understandably a little confusing). I believe that this is
what it uses...
https://gitweb.torproject.org/debian/tor.git/blob/HEAD:/debian/tor-service-defaults-torrc