[ntp:questions] Re: ntp.conf For Clients
Danny Mayer
mayer at gis.net
Wed Jun 22 03:15:42 UTC 2005
David Woolley wrote:
> In article <mailman.104.1119362028.91305.questions at lists.ntp.isc.org>,
> Stewart Pelegan <spelegan at csc.com> wrote:
>
>
>>Right now, I've got the following in the clients' ntp.conf:
>
>
>>broadcastclient
>>multicastclient 224.0.1.1
>
>
> It's not very sensible to have both. You should get things working
> properly without multi/broad-cast before you add this complication.
>
Actually there's nothing wrong with this if they are coming from
different places. I wouldn't do it if initially setting up.
>
>>enable auth monitor
>
>
> I'm not an expert on auth, but you should not have it, initially,
> when debugging without broadcast. I think it may be needed for
> broadcast modes. I cannot see any indication of the key files
> that it must need.
>
broadcast and multicast have auth enabled by default. I'd turn it
off initially when starting a configuration. However your server
is not sending broadcast packets. Are you getting them from
elsewhere?
>
>>and the servers have:
>
>
>>server 127.127.5.0 prefer
>>server 10.20.30.41
>>server 127.127.1.0
Add iburst to get things set up quickly.
>>fudge 10.20.30.41 stratum 1
>
>
> The stratum 1 here will be ineffective.
>
>
>>fudge 127.127.1.0 stratum 1
>
>
> Setting a local clock to stratum one is not something you want to
> do lightly. I can see no valid reason for doing it here. I am pretty
> sure that having this local clock will make the configuration unstable
> when the radio clocks fail. The only time to have one at stratum one
> is if the local clock is being disciplined by something other than ntpd,
> and even then there is the problem that ntpd will not know if that
> source has failed.
>
>
>>broadcast 224.0.1.1 ttl 6
>
>
> ttl 6 is too large if all the clients are on the same sub-net. Simple
> broadcast would be enough.
>
The ttl is in fact a hop count. You are unlikely to need more than a ttl
of 2 and you certainly shouldn't propogate more than you need. You are
better leaving it at the default.
Danny
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