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I need to set my laptop as an NTP server within my own local area network.

From what I notice, I am able to sync the client to my NTP server in a local area network ONLY when

a.) There is an internet connection.
b.) When I tried to connect to another LAN without internet access, I still managed to sync the computer.

There are two LANs that I connected to:

1.) 192.168.1.x subnet with internet
2.) 192.168.2.x subnet without internet

Here is the server. As you can see, when I tried restarting the service when I am connected to the LAN without the internet, I failed to sync with the client.

Server

See, I failed to sync. However, if I am connected to the internet, all is well. How can I setup the NTP server such that even though I do not have any internet connection, my laptop can still act as an NTP server that my clients in the LAN will be able to sync to??

Client

I also included here what my /etc/ntp.conf as it may provide information about where I lack.

# /etc/ntp.conf, configuration for ntpd; see ntp.conf(5) for help

driftfile /var/lib/ntp/ntp.drift


# Enable this if you want statistics to be logged.
#statsdir /var/log/ntpstats/

statistics loopstats peerstats clockstats filegen loopstats file loopstats type day enable filegen peerstats file peerstats type day enable filegen clockstats file clockstats type day enable

# Specify one or more NTP servers.

# Use servers from the NTP Pool Project. Approved by Ubuntu Technical Board
# on 2011-02-08 (LP: #104525). See http://www.pool.ntp.org/join.html for
# more information. server 0.ubuntu.pool.ntp.org server 1.ubuntu.pool.ntp.org server 2.ubuntu.pool.ntp.org server 3.ubuntu.pool.ntp.org server 127.127.1.0 fudge 127.127.1.0 stratum 10

# Use Ubuntu's ntp server as a fallback. server ntp.ubuntu.com

# Access control configuration; see /usr/share/doc/ntp-doc/html/accopt.html for
# details.  The web page <http://support.ntp.org/bin/view/Support/AccessRestrictions>
# might also be helpful.
#
# Note that "restrict" applies to both servers and clients, so a configuration
# that might be intended to block requests from certain clients could also end
# up blocking replies from your own upstream servers.

# By default, exchange time with everybody, but don't allow configuration. restrict -4 default kod notrap nomodify nopeer noquery restrict -6 default kod notrap nomodify nopeer noquery

# Local users may interrogate the ntp server more closely. restrict 127.0.0.1 restrict ::1

# Clients from this (example!) subnet have unlimited access, but only if
# cryptographically authenticated.
#restrict 192.168.123.0 mask 255.255.255.0 notrust


# If you want to provide time to your local subnet, change the next line.
# (Again, the address is an example only.)
#broadcast 192.168.1.255
#broadcast 192.168.2.255

# If you want to listen to time broadcasts on your local subnet, de-comment the
# next lines.  Please do this only if you trust everybody on the network!
#disable auth
#broadcastclient

# Allow LAN machines to synchronize with this ntp server
#restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
#restrict 192.168.2.0 mask 255.255.255.0 nomodify notrap
  • If you have router, server, basically anything that's online all the time, you'd better use that. A laptop isn't such a good choice for an NTP server because it's not always online. – Jan Sep 3 '14 at 12:39
  • But is it possible to sync with the router not connected to the internet? I only need to sync time with my computer for my thesis. I do not need a very accurate time. I just need the different computers synced at the same time. Also, for the working environment, internet is not always present. What we only need is the Wi-Fi and not the internet. – Xegara Sep 3 '14 at 12:50
1

I stumbled with a fix. :-)

Edit the file /etc/ntp.conf

#add these
server 127.127.1.0 iburst
fudge 127.127.1.0 stratum 10

And comment out all other servers. :-)

P.S. I'm not sure about the iburst. I guess it can also be not included.

  • Just for reference, to all other people that might read this: In >= 99% of all usecases it is utter nonsense to use a device that's not always on as NTP server. There's nothing wrong with the machine not having internet access and there's no need for the server to have the accurate time, although it's preferable. – Jan Sep 3 '14 at 19:33

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