[chrony-users] Interop with NTP version 1 and 4 clients

[Benny Lyne Amorsen <benny@xxxxxxxxxx>]

Chrony is working very well as an NTP server (not a stratum 1 of
course). However, certain client requests get no answer and others get a
surprising one.

Some clients use the SNTP protocol, which I believe is also known as NTP
version 1? Those clients do not receive an answer at all. This is
unfortunate since they are SIP phones and have no other way of acquiring
time.

Here is the tcpdump of a client indicating NTPv4 but receiving an NTPv3
answer. The client then proceeds to ignore that answer and repeats the
question.

15:03:55.712716 IP (tos 0x0, ttl 59, id 0, offset 0, flags [DF], proto UDP (17), length 76)
    x.x.x.x.1011 > y.y.y.y.ntp: NTPv4, length 48
	Client, Leap indicator:  (0), Stratum 0 (unspecified), poll 0s, precision 0
	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:   3570271435.694462001 (2013/02/19 15:03:55)
	    Originator - Receive Timestamp:  0.000000000
	    Originator - Transmit Timestamp: 3570271435.694462001 (2013/02/19 15:03:55)
15:03:55.712877 IP (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto UDP (17), length 76)
    y.y.y.y.ntp > x.x.x.x.1011: NTPv3, length 48
	Server, Leap indicator:  (0), Stratum 4 (secondary reference), poll 0s, precision -19
	Root Delay: 0.009262, Root dispersion: 0.019210, Reference-ID: 217.195.186.210
	  Reference Timestamp:  3570271416.234727978 (2013/02/19 15:03:36)
	  Originator Timestamp: 3570271435.694462001 (2013/02/19 15:03:55)
	  Receive Timestamp:    3570271435.712715923 (2013/02/19 15:03:55)
	  Transmit Timestamp:   3570271435.712865889 (2013/02/19 15:03:55)
	    Originator - Receive Timestamp:  +0.018253916
	    Originator - Transmit Timestamp: +0.018403917


By the way, what happened to the gmane mailing list subscription? The last mail on gmane is from 2009...


Thanks for a great piece of software!


/Benny



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