[ntp:questions] xntp both serve and client

David Woolley david at ex.djwhome.demon.co.uk.invalid
Thu Nov 6 07:52:02 UTC 2008

fenwayfool wrote:

> NTP seems a bit more involved.  It even seems like if I configure a
> server... and the code has trouble reaching the server... that it may
> revert into a "listen to NTP broadcast messages" like mode???  Not
> sure about that but some comments suggest it at first glance.  That
> would be another reason to keep port 123 open, I guess.

broadcastclient mode has to be explicitly configured, but that is 
something that is quite commonly done by people who are operating ntpd 
in a pure client mode.

The problem with only temporarily opening the socket during a poll is 
that it has to be treated as a special case which can only be enabled if 
  none of acting as a server, broadcastclient, or management 
capabilities are in use.  (A lot of pure client users also want remote 
access to management statistics.)

Also there will still be a proportion of the time in which the port is 
open, so it could still show up on scans.

More information about the questions mailing list