NTP problem

Csaba Gal · ‎02-16-2010

Hi,

I want to make a C3550 synced to an ntp server. But it doesn't work.

Theese are the details:

ntp_sw#sh ver
Cisco Internetwork Operating System Software
IOS (tm) C3550 Software (C3550-I9Q3L2-M), Version 12.1(19)EA1c, RELEASE SOFTWARE (fc2)
Copyright (c) 1986-2004 by cisco Systems, Inc.
Compiled Tue 03-Feb-04 04:47 by yenanh

ntp_sw#sh ntp statu
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 250.0000 Hz, actual freq is 250.0000 Hz, precision is 2**18
reference time is 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)
clock offset is 0.0000 msec, root delay is 0.00 msec
root dispersion is 0.00 msec, peer dispersion is 0.00 msec

ntp_sw#sh ntp assoc det
10.100.40.31 configured, insane, invalid, unsynced, stratum 16
ref ID 0.0.0.0, time 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)
our mode client, peer mode unspec, our poll intvl 64, peer poll intvl 64
root delay 0.00 msec, root disp 0.00, reach 0, sync dist 0.000
delay 0.00 msec, offset 0.0000 msec, dispersion 16000.00
precision 2**5, version 3
org time 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)
rcv time 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)
xmt time AF3BF73F.5E0B2D3C (03:45:19.367 CET Mon Mar 1 1993)
filtdelay = 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
filtoffset = 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
filterror = 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0 16000.0

ntp_sw#ping 10.100.40.31

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.100.40.31, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/1/4 ms

Debug log:

002260: *Mar 1 02:44:15: NTP: xmit packet to 10.100.40.31:
002261: *Mar 1 02:44:15: leap 3, mode 3, version 3, stratum 0, ppoll 64
002262: *Mar 1 02:44:15: rtdel 0000 (0.000), rtdsp 10001 (1000.015), refid 00000000 (0.0.0.0)
002263: *Mar 1 02:44:15: ref 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)
002264: *Mar 1 02:44:15: org 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)
002265: *Mar 1 02:44:15: rec 00000000.00000000 (01:00:00.000 CET Mon Jan 1 1900)
002266: *Mar 1 02:44:15: xmt AF3BF6FF.5E0B6472 (03:44:15.367 CET Mon Mar 1 1993)
002267: *Mar 1 02:44:15: NTP: rcv packet from 10.100.40.31 to 10.100.40.60 on Vlan801:
002268: *Mar 1 02:44:15: leap 0, mode 4, version 3, stratum 1, ppoll 64
002269: *Mar 1 02:44:15: rtdel 0000 (0.000), rtdsp 0087 (2.060), refid 50505300 (80.80.83.0)
002270: *Mar 1 02:44:15: ref CF2516D5.434E9813 (14:06:29.262 CET Tue Feb 16 2010)
002271: *Mar 1 02:44:15: org AF3BF6FF.5E0B6472 (03:44:15.367 CET Mon Mar 1 1993)
002272: *Mar 1 02:44:15: rec CF2516DC.600B5675 (14:06:36.375 CET Tue Feb 16 2010)
002273: *Mar 1 02:44:15: xmt CF2516DC.600D5E8D (14:06:36.375 CET Tue Feb 16 2010)
002274: *Mar 1 02:44:15: inp AF3BF6FF.5E67F8E4 (03:44:15.368 CET Mon Mar 1 1993)

Currently I'm not using any ACL.

Thanks

Gryzly

Csaba Gal · ‎02-18-2010

It's solved.. I don't know why but after removing the source interface from the ntp server command and waiting some time, it started to working..

Ganesh Hariharan · ‎02-18-2010

It's solved.. I don't know why but after removing the source interface
from the ntp server command and waiting some time, it started to
working..

Hi,

That Great that ntp is now sync anyway If you say if you have removed the ntp source command from router and then it works it can be possible that ntp source interface is not able to communicate with ntp server to do a check just do extended ping from router making source interface as configured one and then check it is reachable or not.

And just for your information whenever you see insane then it can be possible that In NTP, the device checks for the sanity (validity) of the incoming NTP packets that it receives from the server. If the basic sanity checks fail, it is considered to be invalid or 'insane'.

Following eight validity (sanity) tests are specified in the RFC1305 to test the reply packet received from the server:

Test Number Mask Meaning
~~~~~~~~~~~ ~~~~ ~~~~~~~
1           0x01 Duplicate packet received
2           0x02 Bogus packet received
3           0x04 Protocol unsynchronized
4           0x08 Peer delay/dispersion failed boundary check
5           0x10 Peer authentication failed
6           0x20 Peer clock unsynchronized (common for unsynched server)
7           0x40 Peer stratum out of bound
8           0x80 Root delay/dispersion failed boundary check
Packet data is valid if test 1 to 4 is passed. Then the data will be used to calculate offset, delay, and the dispersion. Packet header is valid if test 5 to 8 is passed.Only packet with valid header can be used to determine whether a peer can be selected for synchronization.

Hope to help !!

Ganesh.H