[ntp:hackers] [Pool] Pool, IPv6

Kurt Roeckx kurt at roeckx.be
Sat May 12 11:09:03 UTC 2012


On Sat, May 12, 2012 at 03:09:34AM -0700, Hal Murray wrote:
> 
> How many people are testing the client side of the pool command using a 
> recent ntp-dev?  How many of you are using IPv6?

You mean that the latest stable release still doesn't support
this?

> Do you think it is ready for general release?
> 
> Will a ntp.conf as simple as "pool distro.pool.ntp.org" work correctly?

$ host debian.pool.ntp.org
Host debian.pool.ntp.org not found: 3(NXDOMAIN)

And 0.debian.pool.ntp.org only gives me 3 IP addresses.

> I'll be glad to summarize off list if you want to reduce clutter.  Please 
> send to the list(s) if you have interesting observations.
> 
> ----------------
> 
> I've been running a couple of boxes using the pool command.  Here is my list 
> of bugs/quirks/comments:
> 
> 1] How many servers should the pool command collect?  The parameter is 
> maxclock which defaults to 10.  I don't care what the answer is, but that 
> seems high to me.  Is the pool project ready to support that much traffic?  
> If not, we have to fix the code or make sure that the sample ntp.conf in all 
> the distros include setting maxclock correctly.
> 
> Should the default maxclock be (automagically) "fixed" if the parser finds a 
> pool command?

We now ship with 4 server lines in the config file.  I epxect the
pool command to collect at least 4 different servers.  I
understand the ntp algorithm requires 3 servers to work properly.

I see a lot of crappy pool servers which makes it hard for ntpd to
actually find a good server, and I think think more servers helps
ntp find the right one.

But I don't see the point of more than 5, specially if ntpd tries
to remove the bad servers itself.

> 3) When the pool command adds a server, it doesn't fire off a request packet. 
>  You have to wait a polling cycle for the first one.
> 
> See above comment.  This makes it look like things aren't working for some 
> mysterious reason.
> 
> https://support.ntp.org/bugs/show_bug.cgi?id=1957
>   Slow startup if using the pool command

Does that also mean that people could potentionally hang during
boot because the pool command is still trying to find servers, and
some services are waiting for ntpd to say it's started?



Kurt



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