Getting NTP (ntpd, ntpdate) to work

Nick Withers nick at
Sun Jun 18 09:34:38 UTC 2006

On Sat, 17 Jun 2006 21:30:55 -0400 (EDT)
Charles Bacon <crtb at> wrote:

> Since FreeBSD 4.5-Release, I have been unable to get NTP working on
> my two FreeBSD computers, one running 5.3Release and the other on
> 6.1Release.  I have done nothing with the GENERIC kernel on either
> machine.  I talk SSH between them, and have been running ntpd on
> both, each naming the other as well as two external servers.
> My network is a typical home net, using 192.168.1/28, 

You mean /24 (i.e.:, Class C), yeah?

> served by a DSL router which does NAT for my external traffic.
> Internal comms. is through switches, plus one hub.  Each computer
> (plus some others running Windows) has easy access out, and is
> invisible from the Internet exceptt for responses.
> Here's my ntp.conf, identical on my two computers:
>  	server
>  	server
>  	driftfile /var/db/ntp.drift
>  	logfile /var/log/ntplog
>  	pidfile /var/run/
>  	logconfig =all
>  	peer
>  	peer		(much comments removed)
> With mediocre diagnostic skill, I have finally discovered tcpdump.
> It told me after much experiment, that the relevant port (NTP, 123) was
> unreachable.  This sounds significant, but I can't find a list of the
> reachability of ports.

Try netstat(1). "netstat -anp udp" might be of help in
particular, here.

> I've looked at ng*, mac_* and pf* and finally bpf*, and only the last seems
> to exist in /dev.
> I had expected that GENERIC would impose only slight filtering somehow,
> and certainly not shut off NTP!  I guess I need help.

If you've loaded a firewall such as IPFW in /etc/rc.conf a
kernel module will be loaded for it, if it's not compiled
statically into hte kernel already (which it isn't on GENERIC
for either 5.3-RELEASE or 6.1-RELEASE). "kldstat" will list
loaded modules (and the IPFW module is ipfw.ko).

> Thanks for any help you can give, and I accept any opprobrium for trying
> to be a sysadmin, even for my home boxen.
>  	Chuck Bacon -- crtb at
Nick Withers
email: nick at
Mobile: +61 414 397 446

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