[ntp:questions] ntpdate works, but ntpd doesn't (reach = 0)

Martin Burnicki martin.burnicki at meinberg.de
Wed Feb 4 09:02:02 UTC 2009


sorry for the late reply, I've been offline for a few days.

Danny Mayer wrote:
> Martin Burnicki wrote:
>> Lizvette,
>> Lizvette Malave wrote:
>>> ntpdate timeServer (without the -u option) works too.
>>> Is there a way to make the ntpd use a different port?
>> If "ntpdate timeServer" works then this does not seem to be a firewall
>> issue.
> On the contrary. Some people block outgoing packets from privileged
> ports like 123/UDP. ntpdate uses a non-privileged port and is therefore
> not blocked.

What you wrote above about port usage by ntpdate is not correct and you
should know this.

By default ntpdate sends and receives packets via port 123/UDP. It *only*
sends via an unprivileged port if either -q (query only), -u (unpriv.
port), or -d (debug) is given on the command line.

This is also the reason why ntpdate by default refuses to work if ntpd is
already running, which is AFAIK by design.

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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