Lotsa reading upon IOS-12.1 and restricting access to the NTP
service running on my cisco switches
{shake,rattle,roll}.marshlabs.gaertner.de
It turns out that IOS is employing something quite similiar (but
a bit simpler) as ntp.org-ntpd with its
restrict clauses. Also learned: using
ntpdc (in particular where ntpq does not
exist).