Questions about the NTP time server sync

Hi folks, I have developed a Linux server for my customer. After migrating the server to my customer site, I was trying to sync its time to the NTP time servers at my customer site.
Below is the ntp.conf:
% vi /etc/ntp.conf
# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
restrict default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery
# Permit all access over the loopback interface. This could
# be tightened as well, but to do so would effect some of
# the administrative functions.
restrict 127.0.0.1
restrict -6 ::1
# Hosts on local network are less restricted.
#restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
# Use public servers from the pool.ntp.org project.
# Please consider joining the pool.
server 10.106.90.172 # NTP server 1
server 10.106.90.173 # NTP server 2
server 203.117.180.36 # External NTP server 3
#broadcast 192.168.1.255 key 42 # broadcast server
#broadcastclient # broadcast client
#broadcast 224.0.1.1 key 42 # multicast server
#multicastclient 224.0.1.1 # multicast client
#manycastserver 239.255.254.254 # manycast server
#manycastclient 239.255.254.254 key 42 # manycast client
# Undisciplined Local Clock. This is a fake driver intended for backup
# and when no outside source of synchronized time is available.
server 127.127.1.0 # local clock
fudge 127.127.1.0 stratum 10
# Drift file. Put this in a directory which the daemon can write to.
# No symbolic links allowed, either, since the daemon updates the file
# by creating a temporary in the same directory and then rename()'ing
# it to the file.
driftfile /var/lib/ntp/drift
# Key file containing the keys and key identifiers used when operating
# with symmetric key cryptography.
keys /etc/ntp/keys
# Specify the key identifiers which are trusted.
#trustedkey 4 8 42
# Specify the key identifier to use with the ntpdc utility.
#requestkey 8
# Specify the key identifier to use with the ntpq utility.
#controlkey 8

I could ping the ip addresses of the time servers from the Linux server.
However, the server time is still unable to sync with any of the time servers.

  1. Do i need to execute the following command for the 1st time to sync the server to the time servers?
    $su -
    #<type the root password>
    #service ntpd stop
    #ntpdate -u <ip of the server with which you want to synchronise>
    #ntpdate -u <ip of the server with which you want to synchronise>
    #ntpdate -u <ip of the server with which you want to synchronise>
    #service ntpd start

  2. Can you also advice how long does it take for the Linux server to sync to the time servers?

  3. Do we need to stop ntpd and manually synchronize the time?

Thanks :slight_smile:

hi,

  1. restarting ntp daemon on the local server should suffice for the daemon to re-read its configuration file. Check if ntp server are behind a firewall (udp port 123 needs to be open for connecctions fromyour local server to the ntp server).

  2. it may vary, but usually I saw synchronization after a few minutes (you can also query with ntpq -p to see infos about the peers).

  3. no, see answer 1.

anyway, which distro/version are you running on the local linux server?

see ya
fra

Hi Fra, thanks for your reply.
Can you advise me whether is there an interval time for subsequent sync?
If yes, how can i change the interval time?

---------- Post updated at 06:51 PM ---------- Previous update was at 04:24 PM ----------

What is the max & min polling interval?
How can i change it on the Linux server?