[ntp:questions] Is it possible to run ntpd server behind a firewall?

Steve Kostecke kostecke at ntp.org
Wed Oct 17 12:06:04 UTC 2007

On 2007-10-17, Shaochun Wang <scwang at ios.ac.cn> wrote:

> The stupid net administrator of my institute blocked all UDP datagram
> in the firewall.

Are you sure that _all_ UDP ports have been blocked? Perhaps it's just
the privileged ports.

> I know that NTP uses UDP to do its work, but is it
> possible to let ntpd use TCP?

As has been stated elsewhere, no.

> Thank you for any suggestion.

1. htpdate - http://www.clevervest.com/htp/

2. get a GPS timing receiver

3. JJY - http://en.wikipedia.org/wiki/JJY - if you're close enough

4. If the non-priviledged UDP ports are open you could recompile ntpd
to use a source port greater than 1024

Steve Kostecke <kostecke at ntp.org>
NTP Public Services Project - http://support.ntp.org/

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