Re: [gentoo-user] NTP problem

["Anthony E. Caudel" <acaudel@gt.rr.com>]

Brandon Enright wrote:

> 
> So from your output a couple issues stick out.  You're only peering with
> one machine which generally doesn't work so well.  You're probably
> better off just using ntpdate periodically if you are only going to
> sample one server.
> 
> Also, the delay on the server you are polling is over 200 ms.  I'm not
> sure where ntp3.usv.ro is located but it is over 260ms for me too.  With
> this high network delay, slight network jitter can make your clock think
> it is way off.  Your machine thinks it is 7.3 ms off.  If you had more
> servers to peer with and *much* lower average delay between those
> servers your clock would stabilize.  As it stands now, you clock
> probably won't ever stabilize because your network is the primary source
> of uncertainty.
> 
> For comparison, here is my ntpq -c rv output:
> 
> assID=0 status=06f4 leap_none, sync_ntp, 15 events,
> event_peer/strat_chg,
> version="ntpd 4.2.0a@1.1190-r Mon Oct 17 21:31:52 PDT 2005 (1)"?,
> processor="i686", system="Linux/2.6.10-gentoo-r6", leap=00, stratum=2,
> precision=-20, rootdelay=21.642, rootdispersion=41.662, peer=12542,
> refid=132.249.20.88,
> reftime=c7a70d4a.975935fc  Wed, Feb 22 2006 16:18:18.591, poll=10,
> clock=0xc7a70dc0.a5847f56, state=4, offset=-0.007, frequency=-31.438,
> noise=1.052, jitter=2.529, stability=3.132
> 
> Notice my offset is pretty marginal and rootdelay is rather low.  If you
> can get your root delay down you should see your offset and stability
> improve.
> 
> Brandon
> 

Well, overnight it only reset twice; - some improvement!

Here is my complete ntp.conf:

------------------------------------------------------------
# NOTES:
#  - you should only have to update the server line below
#  - if you start getting lines like 'restrict' and 'fudge'
#    and you didnt add them, AND you run dhcpcd on your
#    network interfaces, be sure to add '-Y -N' to the
#    dhcpcd_ethX variables in /etc/conf.d/net

# Name of the servers ntpd should sync with
# Please respect the access policy as stated by the responsible person.
#server         ntp.example.tld         iburst

server pool.ntp.org

##
# A list of available servers can be found here:
# http://www.pool.ntp.org/
# http://www.pool.ntp.org/#use
# A good way to get servers for your machine is:
# netselect -s 3 pool.ntp.org
##

# you should not need to modify the following paths
driftfile       /var/lib/ntp/ntp.drift

#server ntplocal.example.com prefer
#server timeserver.example.org

# Warning: Using default NTP settings will leave your NTP
# server accessible to all hosts on the Internet.

# If you want to deny all machines (including your own)
# from accessing the NTP server, uncomment:
#restrict default ignore


# To deny other machines from changing the
# configuration but allow localhost:
restrict default nomodify nopeer
restrict 127.0.0.1


# To allow machines within your network to synchronize
# their clocks with your server, but ensure they are
# not allowed to configure the server or used as peers
# to synchronize against, uncomment this line.
#
#restrict 192.168.0.0 mask 255.255.255.0 nomodify nopeer notrap
-------------------------------------------------------------------

Notice I'm using pool.ntp.org. I thought that picked a random server.
In any event, I restarted ntpd and it picked a different server.

ntpq -c peers is now:
------------------------------------------------------------------------------
remote          refid      st t when poll reach   delay   offset  jitter
==============================================================================
*Time2.Stupi.SE  .PPS       1 u   33   64  177  159.568   -4.188   5.881
------------------------------------------------------------------------------

We'll see how this works out.

Tony
-- 
Those who would give up essential Liberty, to purchase a little temporary
Safety, deserve neither Liberty nor Safety.
   -- Benjamin Franklin
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