[ntp:questions] NTP not synchronizing to server

george_joby kottayamachayen at gmail.com
Sat Jan 6 19:42:29 UTC 2007


Hi

I am trying to configure NTP for Redhat Linux AS 4 update 4 running in
DL585 with Windows Server 2003.
My ntp is no longer synchronizing with the servers specified in
ntp.conf

Client: Redhat Linux ntp.conf

server 172.16.0.201 prefer


server 127.127.1.0 # local clock
fudge 127.127.1.0 stratum 10
driftfile /var/lib/ntp/drift
broadcastdelay 0.008
restrict 127.0.0.1


Server: Windows 2003

As mentioned in
http://www.timetools.co.uk/support/windows-2003-ntp-time-server.htm

Now the /var/log/messages shows:

Jan  5 19:00:50 txnaslload03 ntpdate[3028]: step time server
16.74.32.162 offset 3597.014966 sec
Jan  5 19:00:50 txnaslload03 ntpd:  succeeded
Jan  5 19:00:50 txnaslload03 ntpd[3032]: ntpd 4.2.0a at 1.1190-r Thu Apr
20 11:28:36 EDT 2006 (1)
Jan  5 19:00:50 txnaslload03 ntpd[3032]: precision = 1.000 usec
Jan  5 19:00:50 txnaslload03 ntpd[3032]: Listening on interface
wildcard, 0.0.0.0#123
Jan  5 19:00:50 txnaslload03 ntpd[3032]: Listening on interface
wildcard, ::#123
Jan  5 19:00:50 txnaslload03 ntpd[3032]: Listening on interface lo,
127.0.0.1#123
Jan  5 19:00:50 txnaslload03 ntpd[3032]: Listening on interface eth0,
16.74.35.185#123
Jan  5 19:00:50 txnaslload03 ntpd[3032]: Listening on interface eth1,
192.168.36.91#123
Jan  5 19:00:50 txnaslload03 ntpd[3032]: Listening on interface eth2,
172.16.0.200#123
Jan  5 19:00:50 txnaslload03 ntpd[3032]: kernel time sync status 0040
Jan  5 19:00:50 txnaslload03 ntpd: ntpd startup succeeded

[root at txnaslload03 etc]# ntpq -p
     remote           refid      st t when poll reach   delay   offset
jitter
==============================================================================
 172.16.0.201    .LOCL.           1 u   59   64    3    0.413   12.476
 7.679
 LOCAL(0)        LOCAL(0)        10 l   59   64    3    0.000    0.000
 0.001

TCPDUMP from REDHAT:

[root at txnaslload03 ~]# tcpdump -i eth2 -vv "port 123"
tcpdump: listening on eth2, link-type EN10MB (Ethernet), capture size
96 bytes

19:00:51.917563 IP (tos 0x10, ttl  64, id 0, offset 0, flags [DF],
proto 17, length: 76) 172.16.0.200.ntp > 172.16.0.201.ntp: [bad udp
cksum 4dd7!] NTPv4, length 48
        Client, Leap indicator: clock unsynchronized (192), Stratum 0,
poll 6s, precision -20
        Root Delay: 0.000000, Root dispersion: 0.000000, Reference-ID:
(unspec)
          Reference Timestamp:  0.000000000
          Originator Timestamp: 0.000000000
          Receive Timestamp:    0.000000000
          Transmit Timestamp:   3377034051.916440010 (2007/01/05
19:00:51)
            Originator - Receive Timestamp:  0.000000000
            Originator - Transmit Timestamp: 3377034051.916440010
(2007/01/05 19:00:51)
19:00:51.917673 IP (tos 0x0, ttl 128, id 55087, offset 0, flags [none],
proto 17, length: 76) 172.16.0.201.ntp > 172.16.0.200.ntp: [udp sum ok]
NTPv3, length 48
        Server, Leap indicator:  (0), Stratum 1, poll 6s, precision -6
        Root Delay: 0.000000, Root dispersion: 10.071197, Reference-ID:
LOCL
          Reference Timestamp:  3377029250.015875000 (2007/01/05
17:40:50)
          Originator Timestamp: 3377034051.916440010 (2007/01/05
19:00:51)
          Receive Timestamp:    3377034051.921875000 (2007/01/05
19:00:51)
          Transmit Timestamp:   3377034051.921875000 (2007/01/05
19:00:51)
            Originator - Receive Timestamp:  +0.005435000
            Originator - Transmit Timestamp: +0.005435000

See    clock unsynchronized and [bad udp cksum 4dd7!]

I have changed the time in Windows server just to check whether the
client is in sync with server.

After some time I got this messages in /var/log/messages
Jan  5 19:04:06 txnaslload03 ntpd[3032]: synchronized to LOCAL(0),
stratum 10
Jan  5 19:19:18 txnaslload03 ntpd[3032]: kernel time sync disabled 0041
Jan  5 19:20:23 txnaslload03 ntpd[3032]: kernel time sync enabled 0001

[root at txnaslload03 etc]# ntpq -pn
     remote           refid      st t when poll reach   delay   offset
jitter
==============================================================================
 172.16.0.201    .LOCL.           1 u   45   64  377    0.217  12624.4
 5.814
*127.127.1.0     LOCAL(0)        10 l   31   64  377    0.000    0.000
 0.001

See it is synchronizing with itself. "synchronized to LOCAL(0)" instead
of server.

19:26:37.229019 IP (tos 0x10, ttl  64, id 0, offset 0, flags [DF],
proto 17, length: 76) 172.16.0.200.ntp > 172.16.0.201.ntp: [bad udp
cksum 87f1!] NTPv4, length 48
        Client, Leap indicator:  (0), Stratum 11, poll 7s, precision
-20
        Root Delay: 0.000000, Root dispersion: 0.012619, Reference-ID:
127.127.1.0
          Reference Timestamp:  3377035546.185166001 (2007/01/05
19:25:46)
          Originator Timestamp: 3377035544.796875000 (2007/01/05
19:25:44)
          Receive Timestamp:    3377035532.174002006 (2007/01/05
19:25:32)
          Transmit Timestamp:   3377035597.229001000 (2007/01/05
19:26:37)
            Originator - Receive Timestamp:  -12.622873008
            Originator - Transmit Timestamp: +52.432125985
19:26:37.229183 IP (tos 0x0, ttl 128, id 60109, offset 0, flags [none],
proto 17, length: 76) 172.16.0.201.ntp > 172.16.0.200.ntp: [udp sum ok]
NTPv3, length 48
        Server, Leap indicator:  (0), Stratum 1, poll 7s, precision -6
        Root Delay: 0.000000, Root dispersion: 10.089080, Reference-ID:
LOCL
          Reference Timestamp:  3377029262.625374972 (2007/01/05
17:41:02)
          Originator Timestamp: 3377035597.229001000 (2007/01/05
19:26:37)
          Receive Timestamp:    3377035609.859375000 (2007/01/05
19:26:49)
          Transmit Timestamp:   3377035609.859375000 (2007/01/05
19:26:49)
            Originator - Receive Timestamp:  +12.630374014
            Originator - Transmit Timestamp: +12.630374014

I have waited for a long and the client never sync with the server.

I have changed the client configuration by giving just the server name.
In that case no sync at all.

Also if I query the server I will get

[root at txnaslload03 ~]# ntpq -p 172.16.0.201
172.16.0.201: timed out, nothing received
***Request timed out

Please help me in this.

Thanks




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