2.11.2014, 0.47, Andreas Krüger kirjoitti:
I don't know why it didn't manage to get its clock synced, despite
sending NTP requests every 32 seconds.
It may well have lost sync exactly _because_ it was sending NTP requests
every 32 seconds.
Many NTP servers will death-kiss and then refuse to service clients that
keep sending NTP requests more often than reasonable.
I understand that client was originally requesting time service too
often from your server. How is your server configured in this respect?
When the sever stops servicing them, the clients often follow the route
"if it doesn't work, try more of the same". Which (of course) doesn't
work. Such clients keep up the bad work of sending packets too fast, so
in consequence they never get un-ignored.
When you reset the NTP configuration, the client probably switched to a
different server. Which may at some point in the future also send a kiss
of death and start to ignore it. In the meantime, the first few packets
which that other server did service allowed the client to sync.
That's a good point. The configuration was "restrict default limited kod
nomodify notrap nopeer noquery", and "discard average 5 minimum 1". 2^5
is 32 seconds.
Sadly I didn't save the transmitted data anywhere, all I have is the
screen output of tcpdump:
21:31:47.015916 IP x.x.x.x.swdtp-sv > 80.69.172.80.ntp: NTPv4, Client,
length 48
21:31:47.016067 IP 80.69.172.80.ntp > x.x.x.x.swdtp-sv: NTPv4, Server,
length 48
21:32:19.107708 IP x.x.x.x.swdtp-sv > 80.69.172.80.ntp: NTPv4, Client,
length 48
21:32:19.107909 IP 80.69.172.80.ntp > x.x.x.x.swdtp-sv: NTPv4, Server,
length 48
21:32:53.199821 IP x.x.x.x.swdtp-sv > 80.69.172.80.ntp: NTPv4, Client,
length 48
21:32:53.199908 IP 80.69.172.80.ntp > x.x.x.x.swdtp-sv: NTPv4, Server,
length 48
21:33:23.290661 IP x.x.x.x.swdtp-sv > 80.69.172.80.ntp: NTPv4, Client,
length 48
21:33:23.290759 IP 80.69.172.80.ntp > x.x.x.x.swdtp-sv: NTPv4, Server,
length 48
It is possible that my server has been sending KoD packets (along with
some non-KoD packets every now and then), but tcpdump doesn't seem to
show if the KoD bit was set with the tcpdump options I had in use at
that time.
_______________________________________________
pool mailing list
[email protected]
http://lists.ntp.org/listinfo/pool
