[ntp:questions] Re: Stratum?

Tapio Sokura oh2kku at iki.fi
Wed Nov 17 17:02:27 UTC 2004

Jan wrote:
> I'm sorry to post this question, which I'm sure must be a FAQ - I 
> haven't been able to find any answer in what docs I have read, though. 
> This is the situation:
> I have an AIX server that I use as the NTP server on our LAN, and a 
> number of clients running a number of UNIXes. All of this seems to works 
> fine, except for the two that run RedHat Linux - they insist that our 
> NTP server is not acceptable because it is 'stratum 16'.

I guess the key here is Red Hat Linux. At some point Red Hat Linux 
changed to shipping a default ntpd configuration file that ignores all 
incoming NTP packets, including responses to sent time queries. I'd 
first comment out the line beginning with "restrict default" in ntp.conf 
on those Red Hat Linux boxes and restart ntpd. If ntpd now achieves 
synchronization (it takes a while, you can watch it with "ntpq -p"), I'd 
know that the problem was with the restrict statement. Then depending on 
the environment I'd either let it be that way or familiarize mysef with 
the restrict syntax to set more fine grained restrictions.

With 4.2 series ntpd, a "restrict default nopeer nomodify notrap" and 
with 4.1 series ntpd a "restrict default nopeer nomodify notrap notrust" 
are reasonable generic defaults.

This indeed is FAQ, if this was the reason to your problem, but I'm not 
sure whether it is in the FAQ..


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