* Paul de Weerd  [2007-10-24 19:28]:

quoted text
> On Wed, Oct 24, 2007 at 10:47:45AM -0500, Boris Goldberg wrote:

> |   May  be  it makes sense to set "-ncv" as a default behavior of rdate, but

> | there is should be a way to synchronize time without running a demon (don't

> | understand  why  are  people  so  aggressive  about that) if you don't need

> | up-to-second  synchronization  (in my case modern hardware goes less than a

> | second off per day, and really old hardware - less than 10 seconds).

>

> The problem here is the jump in time. You repeat a second or more (if

> you have to jump back) or skip some (if you jump forward). This may

> not be a problem for you in particular, but is considered bad in

> general.

rdate can use adjtime, so that point is moot.
> Another issue is the fact that the server you're syncing to may not be

quoted text
> perfectly sync'ed itself. Or maybe there's some (assymmetrical) delay

> in the network. This may make time on your machine somewhat off (this

> isn't as big a problem as the previous, IMO).

this is the key. rdate sets/skews the clock based on a single reply.

which might get affected badly by network issues or whatever, or be

spoofed, or... ntpd doesn't have that problem at all - last not least it

never uses less than 8 packets to form a single update (just picking

that one as example, there is more it can do, because it can develop

thing over TIME instead of a single one-shot update & exit.
and it fixes the clock frequency permanently using adjtick. rdate

doesn't.
> And it's totally unneccessary, simply run ntpd and be done

quoted text
> with it.

exactly.
--

Henning Brauer, hb@bsws.de, henning@openbsd.org

BS Web Services, http://bsws.de

Full-Service ISP - Secure Hosting, Mail and DNS Services

Dedicated Servers, Rootservers, Application Hosting - Hamburg & Amsterdam