[ntp:questions] xntp both serve and client
david at ex.djwhome.demon.co.uk.invalid
Thu Nov 6 07:52:02 UTC 2008
> 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.
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