[ntp:questions] ntp ports
Richard B. Gilbert
rgilbert88 at comcast.net
Mon Nov 10 02:14:38 UTC 2008
Melanie Pfefer wrote:
> What ports need to be opened if my ntp servers are inside a firewall?
> thank you
Port 123. But only if you need to query outside servers or serve time
to systems outside the firewall. If you purchase and install a hardware
reference clock, such as a GPS timing receiver, you can dispense with
access to servers outside the firewall. This is an option reserved for
the utterly paranoid! Normally you would use one or more outside
servers as a backup and sanity check.
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