[ntp:questions] slow start

Danny Mayer mayer at ntp.isc.org
Tue May 29 09:03:09 UTC 2007

Richard B. Gilbert wrote:
> Jammer wrote:
>> Incredibly slow /etc/init.d/ntpd start
>> (it hangs on boot so I do it manually but it is slow).
> <snip>
>> Is it a hardware problem?
>> The computer clock seems to work fine.
>> Should I be able to ping all the ntp servers in my /etc/ntp.conf?
>> I can't.
> Normally, you should be able to ping NTP servers.
> You should not, however, start your troubleshooting by pinging your NTP 
> servers.  Start by pinging something on your local network such as your 
> router or another computer.  Success tells you that your computer is 
> able to talk to your local network.
> If you didn't ping your router, do it now.  If it doesn't respond, you 
> have some idea where to look for your problem.
> Next, ping your ISP's gateway.  If that works, you've established that 
> you can connect to the internet.
> Now try pinging your NTP servers.

Before you do that ping the nameservers listed in the resolv.conf file.
They need to be available in order to resolve the names in your
ntpd.conf file.

> Try ntpdate -dU <server address>
> Do you get a response?  (This should not set your clock, it should just 
> tell you what ntpdate would have done if you had allowed it to.)
> If you get no response, try:
> nslookup <fully qualified domain name of NTP server>

Don't use nslookup, use dig. nslookup is really bad as a diagnostic tool.


> Does that return a numeric IP address in "dotted decimal" form?  It 
> should look like (the numbers will be different; I just 
> pulled those out of my a**!).  If so, DNS is working.  If not, you 
> probably need to get professional help from your ISP's help desk.
> You might also try issuing:
> ntpq -p
> That should list all your configured servers.  The "reach" field should
> show "377" for each server if ntpd has been running for at least 30 
> minutes.  If the reach field shows 0 you are unable to get a reply from 
> that server.  If they all say 0, you have some sort of a configuration 
> or network problem.  If you get some value greater than 0 but less than 
> 377 you are having only partial success reaching your servers.

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