ntpd -U ntp -g

I'm looking through the ntpd docs, and can't find a reference to
   -U
in the ntpd man pages.  It's something that fedora uses in its default
setup:
   ntpd -U ntp -g

That's what I see when I do a ps -a

Now actually, I'm running an ntpd on a server that's supposed to be
accepting time requests.

Yet, when I send a 
  ntpdate 
to that server, I get 
  ntpdate[25004]: no server suitable for synchronization found

If you setup your client server with a /etc/ntp/step-tickers file it
runs ntpdate on startup, and then depends on ntpd to keep the server's
time straight.

Any hints?
   === Al