# Can the port of the ntp server be specified as a value other than 123?



## sdf (Sep 19, 2018)

Hello everyone,

Written in RFC 5905:


> When operating in symmetric modes (1 and 2), this field
> must contain the NTP port number PORT (123) assigned by the IANA.  In
> other modes, it can contain any number consistent with local policy.



But it seems that there are no similar parameters in the configuration of ntpd and OpenNTPd. Is it right?

Thanks.


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## tingo (Sep 25, 2018)

Why would you want to? Every NTP program (serves, clients) uses port 123, so your server wouldn't be able to communicate with anyone.


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## sdf (Sep 25, 2018)

I am just wondering. Assumed to use on the internal network.


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## kpa (Sep 26, 2018)

Technically you can if all your clients have fully configurable NTP clients/servers but as soon as you add something commerial to the mix you must use the standard UDP port 123.


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