NTP client syncs successfully with NTP server within local network but not with the NTP pool servers
I am using ntp 4.2.6p5 on linux.
I setup an NTP server on a machine in another subnet and tried to sync
my machine with the server and it works well. But when I try to use
the pool.ntp.org servers (I tried 0.pool.ntp.org, 1.pool.ntp.org, etc.
and just pool.ntp.org servers), it does not sync.
nslookup on pool.ntp.org as well as 0.pool.ntp.org gives proper DNS
resolution and ping works on the IPs returned by nslookup as well.
Output of iptables grepped for UDP is as follows:
[Thu Feb 10 12:39:14 root@root-ubuntu:~]# iptables -L -n -v | grep udp
92 13001 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0
state RELATED,ESTABLISHED
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0
udp dpt:123
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0
udp dpt:161
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0
udp dpt:443
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0
udp dpt:623
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0
udp dpt:389
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0
udp dpt:636
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0
udp dpt:3268
0 0 ACCEPT udp -- * * 0.0.0.0/0 0.0.0.0/0
udp dpt:3269
Output of the netstat command is as follows:
[Thu Feb 10 12:35:51 root@root-ubuntu:~]# netstat -a | grep udp
udp 0 0 localhost:9473 0.0.0.0:*
udp 0 0 0.0.0.0:asf-rmcp 0.0.0.0:*
udp 0 0 173.39.22.123:ntp 0.0.0.0:*
udp 0 0 localhost:ntp 0.0.0.0:*
udp 0 0 0.0.0.0:ntp 0.0.0.0:*
udp 0 0 all-systems.mcast.net:23000 0.0.0.0:*
udp 0 0 ::1:ntp ::%628620:*
udp 0 0 fe80::222:bdff:feea:9f1f:ntp ::%628620:*
udp 0 0 fe80::222:bdff:feea:9f20:ntp ::%628620:*
udp 0 0 :::ntp ::%628620:*
I am unable to figure out why the sync problem is happening only with
the pool servers and not the local server. The UDP ports in my system
is up. The servers are up. Time however does not sync (It is still
displaying Feb 10.)
Adding my .conf file:
driftfile /tmp/ntp.drift/
server 0.pool.ntp.org
server 1.pool.ntp.org
server 2.pool.ntp.org
server 3.pool.ntp.org
Adding ntpq -p data:
[Thu Feb 10 12:55:51 root@root-ubuntu:~]# ntpq -p 0.pool.ntp.org
remote refid st t when poll reach delay offset jitter
==============================================================================
*64.147.116.229 .ACTS. 1 u 151 1024 377 2.439 -0.632 0.052
+131.107.13.100 .ACTS. 1 u 879 1024 377 27.853 1.041 0.539
-time.nrc.ca 132.246.11.231 2 u 989 1024 377 86.821 -4.132 8.778
-time1.chu.nrc.c 209.87.233.52 2 u 53 1024 377 109.221 3.153 9.377
+dense.utcc.utor 128.100.200.166 2 u 88 1024 377 64.115 -1.841 0.454
-dns4.utoronto.c 128.100.103.253 2 u 167 1024 377 65.252 -43.422 56.093
|
0 |
|
Arpith
1/9/2013 5:41:47 AM
comp.protocols.time.ntp
4895 articles. 
2 followers.
4 Replies
1727 Views
Similar ArticlesOn 09/01/2013 05:41, Arpith Nayak wrote: > I am using ntp 4.2.6p5 on linux. > > I setup an NTP server on a machine in another subnet and tried to sync > my machine with the server and it works well. But when I try to use > the pool.ntp.org servers (I tried 0.pool.ntp.org, 1.pool.ntp.org, etc. > and just pool.ntp.org servers), it does not sync. [] > Adding ntpq -p data: > > [Thu Feb 10 12:55:51 root@root-ubuntu:~]# ntpq -p 0.pool.ntp.org > > remote refid st t when poll reach delay offset jitter > ============================================================================== > *64.147.116.229 .ACTS. 1 u 151 1024 377 2.439 -0.632 0.052 > +131.107.13.100 .ACTS. 1 u 879 1024 377 27.853 1.041 0.539 > -time.nrc.ca 132.246.11.231 2 u 989 1024 377 86.821 -4.132 8.778 > -time1.chu.nrc.c 209.87.233.52 2 u 53 1024 377 109.221 3.153 9.377 > +dense.utcc.utor 128.100.200.166 2 u 88 1024 377 64.115 -1.841 0.454 > -dns4.utoronto.c 128.100.103.253 2 u 167 1024 377 65.252 -43.422 56.093 ================= Arpith, why do you think your own PC is not syncing? What is the output from "ntpq -p" on your own PC? (Your ntpq command to a remote PC is working). Then see: http://support.ntp.org/bin/view/Support/TroubleshootingNTP Paragraph: 9.4. Checking ntpd 's status. Perhaps you need to set the coarse time before starting NTP, or start NTP with the flag which allows it to step the time at startup. I think that's "-g". See, for example: http://www.freebsd.org/cgi/man.cgi?query=ntpd&sektion=8 -- Cheers, David Web: http://www.satsignal.eu
|
|
0 |
|
David
1/9/2013 8:58:51 AM
On 1/9/2013 12:41 AM, Arpith Nayak wrote: > Adding my .conf file: > > driftfile /tmp/ntp.drift/ > server 0.pool.ntp.org > server 1.pool.ntp.org > server 2.pool.ntp.org > server 3.pool.ntp.org > > Adding ntpq -p data: > > [Thu Feb 10 12:55:51 root@root-ubuntu:~]# ntpq -p 0.pool.ntp.org > > remote refid st t when poll reach delay offset jitter > ============================================================================== > *64.147.116.229 .ACTS. 1 u 151 1024 377 2.439 -0.632 0.052 > +131.107.13.100 .ACTS. 1 u 879 1024 377 27.853 1.041 0.539 > -time.nrc.ca 132.246.11.231 2 u 989 1024 377 86.821 -4.132 8.778 > -time1.chu.nrc.c 209.87.233.52 2 u 53 1024 377 109.221 3.153 9.377 > +dense.utcc.utor 128.100.200.166 2 u 88 1024 377 64.115 -1.841 0.454 > -dns4.utoronto.c 128.100.103.253 2 u 167 1024 377 65.252 -43.422 56.093 > _______________________________________________ Of much greater use would be "ntpq -p" from the system having the problem. Is ntpd still running on that system or has it exited. If it has exited, you should check the syslog for any messages. If it hasn't the ntpq output would be the next step to seeing what is happening. By the way, the output of "ntpq -p 0.pool.ntp.org" isn't very useful for another reason. Since this is a roundrobin DNS address, there isn't any guarantee that it is even the same system that the ntpd process is using. Brian.
|
|
0 |
|
Brian
1/9/2013 1:20:07 PM
Arpith Nayak wrote:> Adding my .conf file: > > driftfile /tmp/ntp.drift/ > server 0.pool.ntp.org > server 1.pool.ntp.org > server 2.pool.ntp.org > server 3.pool.ntp.org restrict source nomodify ---------^^^^^^ I don't think it should be needed without other restrict statements, however its worth a try. -- E-Mail Sent to this address <BlackList@Anitech-Systems.com> will be added to the BlackLists.
|
|
0 |
|
E
1/9/2013 5:05:05 PM
In article <kck805$44u$1@dont-email.me>, E-Mail Sent to this address will be added to the BlackLists <Null@BlackList.Anitech-Systems.invalid> writes: >restrict source nomodify >---------^^^^^^ >I don't think it should be needed without other restrict statements, > however its worth a try. I think the first step for debugging restrict statements would be to comment them all out and see if that works. If not, you have another problem. -- These are my opinions. I hate spam.
|
|
0 |
|
hal
1/10/2013 11:14:52 AM