[ntp:questions] NTP timestamps

Chuck Swiger cswiger at mac.com
Tue May 25 20:48:43 UTC 2010


Hi--

On May 25, 2010, at 12:26 PM, Ray wrote:
> Is there a utility that can show me all the timestamps (including the 
> destination timestamp), of an ntp transaction?
> I would like to monitor time asymmetries in network delays across a network.

You've already got one answer, but tcpdump -v also works fine:

47-pi# tcpdump -n -v port ntp
tcpdump: listening on fxp0, link-type EN10MB (Ethernet), capture size 96 bytes
16:46:03.182194 IP (tos 0x0, ttl  47, id 0, offset 0, flags [DF], proto: UDP (17), length: 76) 47.168.78.138.123 > 206.126.224.66.123: NTPv4, length 48
	Client, Leap indicator:  (0), Stratum 4, poll 10s, precision -20
	Root Delay: 0.526123, Root dispersion: 0.095886, Reference-ID: 47.164.128.40
	  Reference Timestamp:  3483808242.403301765 (2010/05/25 16:30:42)
	  Originator Timestamp: 0.000000000
	  Receive Timestamp:    0.000000000
	  Transmit Timestamp:   3483809163.105993810 (2010/05/25 16:46:03)
	    Originator - Receive Timestamp:  0.000000000
	    Originator - Transmit Timestamp: 3483809163.105993810 (2010/05/25 16:46:03)
16:46:03.182329 IP (tos 0x0, ttl  64, id 49409, offset 0, flags [none], proto: UDP (17), length: 76) 206.126.224.66.123 > 47.168.78.138.123: NTPv4, length 48
	Server, Leap indicator:  (0), Stratum 2, poll 10s, precision -19
	Root Delay: 0.024063, Root dispersion: 0.028579, Reference-ID: 18.26.4.105
	  Reference Timestamp:  3483807950.124584538 (2010/05/25 16:25:50)
	  Originator Timestamp: 3483809163.105993810 (2010/05/25 16:46:03)
	  Receive Timestamp:    3483809163.182223864 (2010/05/25 16:46:03)
	  Transmit Timestamp:   3483809163.182292572 (2010/05/25 16:46:03)
	    Originator - Receive Timestamp:  +0.076230054
	    Originator - Transmit Timestamp: +0.076298762

Regards,
-- 
-Chuck




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