[HLUG] NTP nonsense
tundish
tundish at thuswise.org.uk
Tue Nov 22 21:48:39 GMT 2005
Hi, it was great to meet you all last week. Looking forward to the
Christmas meal!
I mentioned to Andrew that I was having trouble with NTP. He suggested I
post the details here.
For those who don't know, the idea with NTP is that when your computer
boots, it runs ``ntpdate`` which goes off and finds a server(s) on the
internet which knows the right time, and corrects your PC's clock to
match that time. Then, the ``ntpd`` daemon takes over and makes sure
your clock is corrected to run the same speed as the server(s). When
your PC has sync'ed up, it gets given a Stratum which shows its place in
the NTP hierarchy. Then *you* can serve time to other machines, ie: the
ones in your LAN. Stratum 1 servers totally know what the time is.
Stratum 16 means you're pants.
I am pants. Although my server can see NTP servers, and can correct its
time, it never seems to synch up. It stays at Stratum 16.
I'm running Gentoo, kernel 2.6.13-gentoo-r3, and ntp 4.2.0. There are a
number of issues I've discovered which may affect NTP operation. For
example, there's an issue with the kernel HZ value being anything other
than 100. I've fixed that. There's an issue with using APM and ACPI, so
I've removed them. I've checked that the ``compatibility`` module
enables NTP running below root. I've removed the problematic keywords
"ignore" and "noserve" from my ntp.conf. My next move will be to get rid
of ntpd altogether and install openntp or chrony.
Hopefully, someone here might spot what I'm doing wrong. Here below is
my ntp/conf, then a sample from ``ntpq -c pe``, then from ``ntpq -c rv``
Anyway, thanks for reading so far, and see you soon.
Cheers,
Dave.
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 uk.pool.ntp.org prefer
server ntp.demon.co.uk
server ntp0.esat.net
server time1.mikes.fi
##
# 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 noquery
restrict 127.0.0.1 nomodify nopeer
#restrict uk.pool.ntp.org noquery nomodify
#restrict ntp.demon.co.uk noquery nomodify
#restrict ntp0.esat.net noquery nomodify
#restrict time1.mikes.fi noquery nomodify
# 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
restrict 192.168.0.0 mask 255.255.0.0 nomodify nopeer notrap
#fudge 127.127.1.0 stratum 10
ntp -c pe::
remote refid st t when poll reach delay offset
jitter
==============================================================================
gw.roaima.co.uk 130.159.196.118 3 u 153 64 14 61.479 923.857
10.405
ntp.demon.co.uk .INIT. 16 u 1853 64 0 0.000 0.000
4000.00
ntp0.esat.net .GPS. 1 u 159 64 14 63.514 923.101
0.240
ntp1.innofactor .INIT. 16 u 789 64 0 0.000 0.000
4000.00
ntpq -c rv::
assID=0 status=c011 sync_alarm, sync_unspec, 1 event, event_restart,
version="ntpd 4.2.0a at 1.1190-r Thu Nov 3 20:21:32 GMT 2005 (1)"?,
processor="i686", system="Linux/2.6.13-gentoo-r3", leap=11, stratum=16,
precision=-20, rootdelay=0.000, rootdispersion=1249.335, peer=0,
refid=INIT, reftime=00000000.00000000 Thu, Feb 7 2036 6:28:16.000,
poll=6, clock=0xc72e082c.5a3161a1, state=1, offset=0.000,
frequency=0.000, noise=0.001, jitter=0.001, stability=0.000
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