Regarding unreachable status at ntpq -p output.

[Minoru Asano]

Hello,

I would like to know regarding ntpq -p output.

[ENVIRONMENT]
RHEL ES4 up3 (x86) , DL380G4

[SITUATION]
The "ntpq -p" output is following at customer site:
# ntpq -p
remote refid st t when poll reach delay offset jitter
==============================================================================
*LOCAL(0) LOCAL(0) 10 l 61 64 377 0.000 0.000 0.002
ntp00 .TJJY. 1 u 56 64 377 2.943 424230. 203492.
dns 10.156.1.40 2 u 52 64 377 1.330 425813. 205701.

At line 2 and 3, it seems be discarded NTP packet because any mark is not set at left column.
The NTP server seems be so far , and unreachable.

[QUESTION]
- Is there any threshold value when NTP server unreachable ?
Is it hop count of router ?
If so, is it due to TTL ?
Please let me know the unreachable mechanism.

Thank you for advice.
Best Regards.
/Minoru.Asano

[Ivan Ferreira]

The offset column indicates the time difference (in miliseconds) between the server and the client. When this number exceeds 128 the message "synchronization lost" shows in the log file.

Try the following:

Stop the ntp service:

service ntpd stop

Resync your server time:

ntpdate -b ntp.server.host

Start the ntp service

service ntpd start

[Andrew Cowan]

Not all ntp servers are setup to reply to anyone. Check with the owner of the system that there are no restrictions set.

[Minoru Asano]

Thank you for quick reply and suggestion.
Can I ask a question again ?

If the system synchronize with NTP server, how long the polling time ?
For example, if it take 5 seconds, the system abandon to synchronize with NTP server, so on.

[QUESTION]
- I would like to know the threshold to abandon for NTP sync.

[ADDITIONAL INFORMATION]
- The ping command is reachable with no lost packet, but NTP sync does not occur because
"reach" field is "0" if we confirm it using "ntpq -p command".

And I ask the customer to confirm whether NTP server restrict the NTP access.

Thank you for advice.
Best Regards.
/Minoru.Asano

[Andrew Cowan]

Minoru,

The default delay is 5000 miliseconds but can be overridden if you run ntpq in interactive mode. Another useful switch is "-d".

NTP is a notoriously fussy program and will fail for the strangest of reasons. Try running "ntpdate" to the server to see if it responds and also try creating an almost empty "ntpd.conf" will that has just the exact parameters you have set.