[ntp:questions] NTP timestamps

Ray rayatnrc at hotmail.com
Tue May 25 21:20:34 UTC 2010


Hello Chuck,

Thanks again.
tcpdump shows the content of the NTP packet.
The destination (or return) timestamp is not in there. It is stamped by the 
NTP daemon itself.

I am also looking for a Linux version so that I can monitor a stratum-1 
server, against a remote server, to see network delays.
Any ideas would be appreciated.

Ray
------------------------
"Chuck Swiger" <cswiger at mac.com> wrote in message 
news:B3E26C0F-262F-48CD-95B4-4A790F5EDB70 at mac.com...
> 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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