[ntp:hackers] Requests for comments on the new "dynamic" keyword

Danny Mayer mayer at ntp.isc.org
Fri Apr 20 04:48:29 PDT 2007

Martin Burnicki wrote:
> Hi all, 
> the keyword "dynamic" has been introduced with ntpd 4.2.4 in order to allow 
> configuration of servers/peers even before there is a known route to that 
> server. See also:
> https://ntp.isc.org/bugs/show_bug.cgi?id=803#c14
> This keyword has nothing to do with delayed DNS lookups.
> In older versions of ntpd, or without the "dynamic" keyword on the server 
> config line, ntpd does not add an association for a server if there's no 
> route to that server when ntpd starts up. Instead, a log entry is generated 
> and the server is discarded.
> If the "dynamic" keyword is present, an association is added even if there's 
> no route to that server when the config file is processed. That server 
> association just stays at reach 0 until there is a route so that the server 
> can be polled. 
> There have also been some recent changes which allow for dynamic interfaces 
> and delayed DNS lookups, which let associations be mobilized delayed when 
> they become reachable. So the behaviour with the "dynamic" keyword being 
> present fits perfectly, and I think this is what normally users would expect 
> from ntpd. 
> So I suggest the "dynamic" behaviour should become the default for ntpd, and 
> since the "dynamic" keyword is obsolete in this case it can be removed.
> What do you think?

I agree. It doesn't seem to be necessary to have it as an option. If
it's really necessary we might want to reverse the logic and have a
"nodynamic" keyword if you really explicitly want to turn it off, but I
would suspect that almost everyone would want it on by default.


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