NTP Configuration without Internet

Question

I am trying to setup a local NTP Server without Internet Connection.

Below is my ntp.conf on Server

# Server 
server 127.127.1.0
fudge 127.127.1.0 stratum 5
broadcast 10.108.190.255

Below is my ntp.conf on Clients

# Clients
server 10.108.190.14
broadcastclient

but my clients are not sync with the server. Output to ntpq -p on Clients show that they are not taking time from the server, and server ip is show at stratum 16

Could any one please help in this issue.

this question belongs on ServerFault, since it's not about software development. — antiduh, Jul 15 '14 at 14:42

score 2 · Answer 1 · answered Jan 29 '14 at 23:14

You need to configure the clients with th e prefer keyword. ntpd tries its hardest not to honor local undisciplined clocks in order to prevent screwups.

server 10.108.190.14 prefer

For more information see: http://www.ntp.org/ntpfaq/NTP-s-config-adv.htm#AEN3658

This is all assuming that you have included the full and entire ntp.con and did not leave out any bits about restrict lines.

Erikw · Accepted Answer · 2021-05-22T11:10:59.740

2

The server should use its local clock as the source. A better set up is to use orphan mode for isolated networks which gives you fail-over. Check out the documentation:

http://www.eecis.udel.edu/~mills/ntp/html/orphan.html

edited May 22 '21 at 11:10

answered Jul 15 '14 at 14:22

Erikw

799
6
18

score 0 · Answer 3 · answered Jun 24 '21 at 11:04

How about using chrony?

Steps

Install chrony in both your devices
```
sudo apt install chrony
```
Let's assume the server IP address 192.168.1.87 then client configuration (/etc/chrony/chrony.conf) as follows:

server 192.168.1.87 iburst

keyfile /etc/chrony/chrony.keys

driftfile /var/lib/chrony/chrony.drift

log tracking measurements statistics

logdir /var/log/chrony
Server configuration (/etc/chrony/chrony.conf), assume your client IP is 192.168.1.14

keyfile /etc/chrony/chrony.keys

driftfile /var/lib/chrony/chrony.drift

log tracking measurements statistics

logdir /var/log/chrony

local stratum 8

manual

allow 192.0.0.0/24 allow 192.168.1.14
Restart chrony in both computers

sudo systemctl stop chrony

sudo systemctl start chrony

5.1 Checking on the client-side,

sudo systemctl status chrony

 `**output**:

            июн 24 13:26:42 op-desktop systemd[1]: Starting chrony, an NTP client/server...

            июн 24 13:26:42 op-desktop chronyd[9420]: chronyd version 3.2 starting (+CMDMON +NTP +REFCLOCK +RTC +PRIVDROP +SCFILTER +SECHASH +SIGND +ASYNCDNS +IPV6 -DEBUG)

            июн 24 13:26:42 op-desktop chronyd[9420]: Frequency -6.446 +/- 1.678 ppm read from /var/lib/chrony/chrony.drift

            июн 24 13:26:43 op-desktop systemd[1]: Started chrony, an NTP client/server.

            июн 24 13:26:49 op-desktop chronyd[9420]: Selected source 192.168.1.87`

5.1 chronyc tracking output:

        Reference ID    : C0A80157 (192.168.1.87)
        Stratum         : 9
        Ref time (UTC)  : Thu Jun 24 10:50:34 2021
        System time     : 0.000002018 seconds slow of NTP time
        Last offset     : -0.000000115 seconds
        RMS offset      : 0.017948076 seconds
        Frequency       : 5.491 ppm slow
        Residual freq   : +0.000 ppm
        Skew            : 0.726 ppm
        Root delay      : 0.002031475 seconds
        Root dispersion : 0.000664742 seconds
        Update interval : 65.2 seconds
        Leap status     : Normal

NTP Configuration without Internet

3 Answers3