Problem with NTP.

Andrew.Bridgeman at corusgroup.com Andrew.Bridgeman at corusgroup.com
Tue Apr 21 11:35:45 UTC 2009



Hello Simon,
                         I have just run the tcpdump command on Eth0 as an
example and it returned tcpdump listening, capture size 96bytes so this
looks to be fine. The Answer to your other questions are below;

1). Yes we are using DHCP service on this machine with bond0.
2). ntpdate -q server1 =   server server 1, stratum 4, offset -0.085034,
delay 0.05925
                  21 Apr 12:19:32 ntpdate[28633]: adjust time server
server1 offset -0.085034 sec
3)ntptrace = localhost.localdomain: stratum 16, offset 0.000000, synch
distance 0.056055
4)nsswitch.conf = services files nis
5)ypcat =   3694/tcp vpntpp         3694/tcp
            119/udp nntp            119/udp           readnews untp
            563/udp nntps           563/udp
            3346/udp trnsprntproxy   3346/udp
            119/tcp nntp            119/tcp           readnews untp
            3346/tcp trnsprntproxy   3346/tcp
            123/udp ntp       123/udp
            563/tcp nntps           563/tcp
            3079/udp lv-frontpanel  3079/udp
            2514/udp facsys-ntp     2514/udp
            2514/tcp facsys-ntp     2514/tcp
            580/udp sntp-heartbeat  580/udp
            3079/tcp lv-frontpanel  3079/tcp
            1865/udp entp           1865/udp
            3178/udp radclientport  3178/udp
            123/tcp ntp       123/tcp
            1865/tcp entp           1865/tcp
            3178/tcp radclientport  3178/tcp
            580/tcp sntp-heartbeat  580/tcp
            5418/udp mcntp          5418/udp
            5418/tcp mcntp          5418/tcp
            3694/udp vpntpp         3694/udp
6). Yes there is a firewall but all hosts have access through it, hence 30
odd machines work currently.
7). Date/Timezone - Tue Apr 21 12:28:38 BST 2009

The interesting one for me out of all the things I have just run is the
ntptrace coming up as stratum16 which I would assume is like a non
communication, if i run this on a machine that works i get stratum 4.

Have a review of this info and let me know your thoughts.

Regards

Andrew Bridgeman



                                                                           
             "Reber, Simon"                                                
             <simon.reber at roch                                             
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             21/04/2009 12:04          RE: Problem with NTP.               
                                                                           
                                                                           
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Andrew,

To make a try run with tcpdump, simply run tcpdump ... This will show
you the entire network traffic from this server.
             To find out more about tcpdump, have a look at the man page:
http://linux.die.net/man/8/tcpdump

About the messages. Are I am right that you also run a DHCP services on
this host?
             And is the interface you are working with bond0?
Do the other servers also have bonding interfaces?

Some other thoughts:
             what does ntpdate -q server1 return?
             what result does ntptrace return?
             what shows cat /etc/nsswitch.conf | grep services
             what shows ypcat -k services | grep ntp
             Is there a firewall between localhost and server1
             What's the date/time and timezone of the server

With the help of the above information, we should be able to fix the
problem (hopefully) ;-)

Cheers,
Simon

>-----Original Message-----
>From: redhat-list-bounces at redhat.com
>[mailto:redhat-list-bounces at redhat.com] On Behalf Of
>Andrew.Bridgeman at corusgroup.com
>Sent: Tuesday, April 21, 2009 12:42 PM
>To: General Red Hat Linux discussion list
>Subject: RE: Problem with NTP.
>
>
>
>Hello Simon,
>                         Thanks for help so far. I have checked and the
>tcpdump package is installed with root permission's so in
>theory we should
>be able to run the tcpdump command. Is there an even simpler tcpdump
>command to run just to check it can be used. Also I have
>attached the last
>25 minutes of the messages log, in which I have restarted the
>ntpd service
>to try and get it too synchronise. If you see anything to investigate
>please let me know.
>
>Apr 21 11:05:06 dhcpd: DHCPREQUEST for Server from
>00:17:a4:f9:6f:fa via
>bond0: unknown lease Server.
>Apr 21 11:05:07 dhcpd: BOOTREQUEST from 00:18:b1:4d:32:00 via
>bond0: BOOTP
>from dynamic client and no dynamic leases
>Apr 21 11:05:44 dhcpd: BOOTREQUEST from 00:18:b1:4d:32:00 via
>bond0: BOOTP
>from dynamic client and no dynamic leases
>Apr 21 11:07:13 dhcpd: BOOTREQUEST from 00:18:b1:4d:32:00 via
>bond0: BOOTP
>from dynamic client and no dynamic leases
>Apr 21 11:09:15 last message repeated 2 times
>Apr 21 11:10:37 dhcpd: BOOTREQUEST from 00:18:b1:4d:32:00 via
>bond0: BOOTP
>from dynamic client and no dynamic leases
>Apr 21 11:12:39 last message repeated 2 times
>Apr 21 11:13:52 dhcpd: BOOTREQUEST from 00:18:b1:4d:32:00 via
>bond0: BOOTP
>from dynamic client and no dynamic leases
>Apr 21 11:14:40 dhcpd: BOOTREQUEST from 00:18:b1:4d:32:00 via
>bond0: BOOTP
>from dynamic client and no dynamic leases
>Apr 21 11:15:52 dhcpd: BOOTREQUEST from 00:18:b1:4d:32:00 via
>bond0: BOOTP
>from dynamic client and no dynamic leases
>Apr 21 11:17:12 last message repeated 2 times
>Apr 21 11:19:15 last message repeated 2 times
>Apr 21 11:19:56 ntpd[26183]: ntpd Thu Nov  6 11:08:22 UTC 2008 (1)
>Apr 21 11:19:56 ntpd[26184]: precision = 1.000 usec
>Apr 21 11:19:56 ntpd[26184]: Listening on interface wildcard,
>0.0.0.0#123
>Disabled
>Apr 21 11:19:56 ntpd[26184]: Listening on interface wildcard, ::#123
>Disabled
>Apr 21 11:19:56 ntpd[26184]: Listening on interface bond0,
>fe80::21e:bff:fe60:acda#123 Enabled
>Apr 21 11:19:56 ntpd[26184]: Listening on interface lo, ::1#123 Enabled
>Apr 21 11:19:56 ntpd[26184]: Listening on interface lo, 127.0.0.1#123
>Enabled
>Apr 21 11:19:56 ntpd[26184]: Listening on interface bond0, Server#123
>Enabled
>Apr 21 11:19:56 ntpd[26184]: kernel time sync status 0040
>Apr 21 11:19:56 ntpd[26184]: frequency initialized 0.000 PPM from
>/var/lib/ntp/drift
>Apr 21 11:20:10 dhcpd: BOOTREQUEST from 00:18:b1:4d:32:00 via
>bond0: BOOTP
>from dynamic client and no dynamic leases
>Apr 21 11:21:13 dhcpd: BOOTREQUEST from 00:18:b1:4d:32:00 via
>bond0: BOOTP
>from dynamic client and no dynamic leases
>Apr 21 11:23:12 last message repeated 2 times
>Apr 21 11:25:01 last message repeated 2 times
>
>Thanks
>
>Andrew Bridgeman
>
>
>
>
>
>             "Reber, Simon"
>
>             <simon.reber at roch
>
>             e.com>
>         To
>             Sent by:                  "General Red Hat Linux
>discussion
>             redhat-list-bounc         list"
><redhat-list at redhat.com>
>             es at redhat.com
>         cc
>
>
>
>    Subject
>             21/04/2009 11:16          RE: Problem with NTP.
>
>
>
>
>
>             Please respond to
>
>              General Red Hat
>
>             Linux discussion
>
>                   list
>
>             <redhat-list at redh
>
>                  at.com>
>
>
>
>
>
>
>
>
>
>Hi Andrew,
>
>Well I think this is going to be a bit more difficult.
>The "timeout" is coming obviously from the ntp settings set on server1
>(noquery, etc.)
>
>Anyway tcpdump is a tool to look at the network traffic and as
>you said,
>it is not possible to find the binary which usually indicates that it
>isn't installed (try to run rpm -qa | grep tcpdump to see if
>it is there
>or not)
>             BTW: The program is under /usr/sbin and needs
>root permissions
>to be executed
>
>So I strongly suggest to install tcpdump to see what is going
>on, on the
>network interface (especially on port 123 since this is the ntp port)
>             An other help could be to check /var/adm/messages
>to see if
>there is any hint why ntp isn't working properly
>
>Cheers,
>Simon
>
>P.S. Sorry for the guessing all the time but it's difficult to give
>advice via email.
>             I have tons of idea where the problems could be
>located but to
>mention all that I would need to write a book ;-)
>
>>-----Original Message-----
>>From: redhat-list-bounces at redhat.com
>>[mailto:redhat-list-bounces at redhat.com] On Behalf Of
>>Andrew.Bridgeman at corusgroup.com
>>Sent: Tuesday, April 21, 2009 11:31 AM
>>To: General Red Hat Linux discussion list
>>Subject: RE: Problem with NTP.
>>
>>
>>
>>Hello Simon,
>>                          When I run the ntpq -p server1
>>command I get an
>>"timeout, nothing received" so I tried the same command on 5
>>other machines
>>that are currently working fine and I get the same error so I
>>am unsure why
>>that is. The tcpdump command is showing no such file or
>>directory, are you
>>sure the syntax is correct?
>>
>>Regards
>>
>>Andrew Bridgeman
>>
>>
>>
>>
>>
>>             "Reber, Simon"
>>
>>             <simon.reber at roch
>>
>>             e.com>
>>         To
>>             Sent by:                  "General Red Hat Linux
>>discussion
>>             redhat-list-bounc         list"
>><redhat-list at redhat.com>
>>             es at redhat.com
>>         cc
>>
>>
>>
>>    Subject
>>             21/04/2009 10:19          RE: Problem with NTP.
>>
>>
>>
>>
>>
>>             Please respond to
>>
>>              General Red Hat
>>
>>             Linux discussion
>>
>>                   list
>>
>>             <redhat-list at redh
>>
>>                  at.com>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>Well as the configuration does work on other hosts, we don't going to
>>focus any further on this.
>>             But what's about the output of ntpq -p <ntp
>source server>
>>             In your example like: ntpq -p Server1
>>
>>What does tcpdump telling you:
>>             Run # tcpdump -i <intergace> -vvv port 123
>>             Is there any activity reported?
>>
>>Cheers,
>>Simon
>>
>>>-----Original Message-----
>>>From: redhat-list-bounces at redhat.com
>>>[mailto:redhat-list-bounces at redhat.com] On Behalf Of
>>>Andrew.Bridgeman at corusgroup.com
>>>Sent: Tuesday, April 21, 2009 11:13 AM
>>>To: General Red Hat Linux discussion list
>>>Subject: RE: Problem with NTP.
>>>
>>>
>>>
>>>
>>>Thanks for the reply Simon. Here is the ntpq and ntp.conf info.
>>>
>>>     remote           refid      st t when poll reach
>delay   offset
>>>jitter
>>>===============================================================
>>>===============
>>> Server1              Server2    4 u    9   64   77   18.104  -1193.4
>>>3.107
>>>  Server2                               Server 3         3  u
>>        5
>>>64      77      19.688      -1188.2      1.623
>>>
>>>
>>>restrict default noquery nomodify
>>>restrict 127.0.0.1
>>>restrict Server1 mask 255.255.255.255 nomodify notrap noquery
>>>restrict Server2 mask 255.255.255.0 nomodify notrap
>>>server Server1 minpoll 4 maxpoll 6
>>>server Server2 minpoll 4 maxpoll 6
>>>driftfile /var/lib/ntp/drift
>>>logfile /var/log/ntp.log
>>>
>>>Remember I use this config for numerous other machines, it is
>>>just this one
>>>I
>>>have an issue with. Any thoughts on possible solutions would be much
>>>appreciated.
>>>
>>>FYI
>>>
>>>When I run ntpq -p on all of our other Linux machines it shows
>>>as below.
>>>
>>>     remote           refid      st t when poll reach
>delay   offset
>>>jitter
>>>===============================================================
>>>===============
>>> +Server1              Server2    4 u    2   64   377
>>18.104  -12.428
>>>8.107
>>>  *server2                               Server 3         3  u
>>>        58
>>>64      377      19.688      -0.482       10.623
>>>
>>>Regards
>>>
>>>Andrew Bridgeman
>>>
>>>
>>>
>>>
>>>
>>>
>>>             "Reber, Simon"
>>>
>>>             <simon.reber at roch
>>>
>>>             e.com>
>>>         To
>>>             Sent by:                  "General Red Hat Linux
>>>discussion
>>>             redhat-list-bounc         list"
>>><redhat-list at redhat.com>
>>>             es at redhat.com
>>>         cc
>>>
>>>
>>>
>>>    Subject
>>>             21/04/2009 09:55          RE: Problem with NTP.
>>>
>>>
>>>
>>>
>>>
>>>             Please respond to
>>>
>>>              General Red Hat
>>>
>>>             Linux discussion
>>>
>>>                   list
>>>
>>>             <redhat-list at redh
>>>
>>>                  at.com>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>Well the root cause of this issue could be located on various places.
>>>             What I can suggest to try is run # ntpq -p <ntp
>>>source server>
>>>             <ntp source server> means the server which you
>>>are trying to
>>>synchronize with
>>>
>>>             If the connection is refused than you know that
>>you have a
>>>permissions problem somewhere.
>>>
>>>             An other option is to show the output of ntpq -p and
>>>/etc/ntp.conf
>>>                         Please make servernames and IP addresses
>>>anonymous.
>>>
>>>Cheers,
>>>Simon
>>>
>>>>-----Original Message-----
>>>>From: redhat-list-bounces at redhat.com
>>>>[mailto:redhat-list-bounces at redhat.com] On Behalf Of
>>>>Andrew.Bridgeman at corusgroup.com
>>>>Sent: Tuesday, April 21, 2009 10:44 AM
>>>>To: redhat-list at redhat.com
>>>>Subject: Problem with NTP.
>>>>
>>>>
>>>>I have a new Redhat version 4 server that was built last
>week. I have
>>>>edited the /etc/ntp.conf and made sure all the entries in the folder
>>>>/etc/ntp are the same as all the other Linux machines we have
>>>>onsite. It
>>>>seems to find time sources as when I use ntpq -p it comes up
>>>>with the name
>>>>and IP Addresses but I just cannot get it too sync i.e. has a
>>>>* or + next
>>>>to server IP Addresses. I have pretty much been through the
>>>>config on the
>>>>machine and the only two things I can see that are different
>>>>is that it is
>>>>using itself for NIS as it is the NIS master and also in the
>>>>/etc/hosts.equiv file it has individual entries not + at trusted
>>>>like all the
>>>>other machines. I do not think these differences are having an
>>>>impact on
>>>>NTP not synchronising but just thought I would mention them anyway.
>>>>
>>>>Does anyone know what I can try to solve this issue as the
>>time on the
>>>>server needs to be the same as all the other machines.
>>>>
>>>>Any help would be much appreciated.
>>>>
>>>>Regards
>>>>
>>>>Andrew Bridgeman
>>>>
>>>>*************************************************************
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This transmission is confidential and must not be used or disclosed by
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misuse of the transmission by anyone.

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