Hitchhiker's Guide to Openbsd

6.12.1 - "But OpenNTPD isn't as accurate as the ntp.org daemon!"
http://www.openbsd.org/faq/faq6.html (29 of 33)9/4/2011 10:02:06 AM

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6 - Networking
That may be true. That is not OpenNTPD's 
design goal
, it is intended to be free, simple, reliable and 
secure. If you really need microsecond precision more than the benefits of OpenNTPD, feel free to use 
ntp.org's ntpd, as it will remain available through ports and packages. There is no plan or desire to have 
OpenNTPD bloated with every imaginable feature. 
6.12.2 - "Someone has claimed that OpenNTPD is 'harmful'!"
Some people have not understood the goals of OpenNTPD -- a simple, secure and easy to maintain way 
to keep your computer's clock accurate. If accurate time keeping is important, a number of users have 
reported better results from OpenNTPD than from ntp.org's ntpd. If security is important, OpenNTPD's 
code is much more readable (and thus, auditable) and was written using native OpenBSD function calls 
like 
strlcpy
, rather than more portable functions like 
strcpy
, and written to be secure from the beginning, 
not "made secure later". If having more people using time synchronization is valuable, OpenNTPD 
makes it much easier for larger numbers of people to use it. If this is "harmful", we are all for it. 
There are applications where the ntp.org ntpd is more appropriate; however it is felt that for a large 
majority of the users, OpenNTPD is more than sufficient. 
A more complete response to this by one of the maintainers of OpenNTPD can be read 
here
. 
6.12.3 - Why can't my other machines synchronize to OpenNTPD?
ntpd(8) does not listen on any address by default. So in order to use it as a server, you have to 
uncomment the "
#listen on *
" line in 
/etc/ntpd.conf
and restart the ntpd(8) daemon. Of course, if 
you wish it to listen on a particular IP address rather than all available addresses and interfaces, replace 
the "*" with the desired address. 
When you have ntpd(8) listening, it may happen that other machines still can't synchronize to it! A 
freshly started ntpd(8) daemon (for example, if you just restarted it after modifying ntpd.conf) refuses to 
serve time information to other clients until it adjusts its own clock to a reasonable level of stability first. 
When ntpd(8) considers its own time information stable, it announces it by a "clock now synced" 
message in 
/var/log/daemon
. Even if the system clock is pretty accurate in the beginning, it can 
take up to 10 minutes to get in sync, and hours or days if the clock is not accurately set at the start.