Hello everyone: I have two vcmp host "A and B,V11.2.1" ,and set up NTP servers,A host NTP time is right ,the other B host is wrong ;tcpdump found A host receive packet ,B host none packet,but A host NTP time is wrong and B host NTP time is right. I have two question need to be helped (1) why A host send ntp request and receive ntp response ,but it's time is wrong ? B host none packet ,but it's time is right. (2)How long send ntp request for BIG-IP ?

Can you provide the output of 'ntpq -pn' on both devices ?

@ lanB, what's the time calibration mechanism of F5 ? I will give you the output of "ntpq -pn" the second day .

I don't understand your question. ntpd uses ntp to keep time like any other unix based device. That's why I need to see the ntp status. A picture of wireshark does not have enough information to draw any conclusions

I want to know how long it will take the NTP client sends a synchronization instructions ?

Perhaps it would help if you read about the NTP protocol. You could start with wikipedia: ntp NTP is a protocol designed to bring multiple clocks into synchronisation with each other.

Ntp Server time correction

8 Replies

IanB
Employee
May 31, 2016
Can you provide the output of 'ntpq -pn' on both devices ?
yuanqiang_22112
Nimbostratus
Jun 06, 2016
@ lanB, what's the time calibration mechanism of F5 ? I will give you the output of "ntpq -pn" the second day .
IanB
Employee
Jun 06, 2016
I don't understand your question. ntpd uses ntp to keep time like any other unix based device. That's why I need to see the ntp status. A picture of wireshark does not have enough information to draw any conclusions
yuanqiang_22112
Nimbostratus
Jun 06, 2016
I want to know how long it will take the NTP client sends a synchronization instructions ?
IanB
Employee
Jun 06, 2016
Perhaps it would help if you read about the NTP protocol. You could start with wikipedia: ntp

NTP is a protocol designed to bring multiple clocks into synchronisation with each other.
yuanqiang_22112
Nimbostratus
Jun 07, 2016
JG
Cumulonimbus
Jun 07, 2016
Are you sure you have not mixed up the identities of these two servers? The non-working server is not initialised and does not even know the type of the peer, whilst the working server gets correct time without going to the network!

From your graph, the polling occurs every 1024 seconds.
IanB
Employee
Jun 07, 2016
In the output you provided, SLB01-LTM-1 is unable to contact the NTP server 3.9.0.1 (or ntpd has only just been started/restarted). .INIT. means it has sent an ntp packet, and is still waiting for a response. It hasn't had any replies (reach is 0). Can you ping 3.9.0.1 from LTM-1 ?

SLB01-LTM-2 is in time sync (the * next to 3.9.0.1 shows that it is in sync), with a stratum 1 time source that claims to be a GPS based clock, and there is no packet loss (reach=0377 octal) to that device.

The output also indicates that your viprion vcmp host (127.3.0.x) is not configured with an NTP source. I suggest you fix that, then your guests can simply sync to that.