Sample ntp.conf
- Kelli Higdon
Owned by Kelli Higdon
Below is a sample of an ntp.conf file. The ntp.conf file is used to sync time from a server that is configured as a Timeserver to the IMG 2020 through the FTP/NTP server that communicates with the IMG 2020. If using Red Hat Enterprise Linux, the file can be modified for your network and loaded into the /etc directory of the FTP/NTP server that is communicating with the IMG 2020. If using an operating system other than linux, it is up to the administrator to know the procedures required to configure the ntp server on that specific OS. The ntp.conf file below can be used as a template if using any operating system other than Red Hat Enterprise Linux. For additional information, refer to the Configure SNTP topic.
#################################################################
# File: ntp.conf
#################################################################
# which logfile group... log to /var/log/messages
# Prohibit general access to this service.
restrict default ignore
restrict 66.187.224.4 mask 255.255.255.255 nomodify notrap noquery
restrict 18.26.4.105 mask 255.255.255.255 nomodify notrap noquery
restrict 128.249.1.10 mask 255.255.255.255 nomodify notrap 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
# -- CLIENT NETWORK -------
# Permit systems on this network to synchronize with this
# time service. Do not permit those systems to modify the
# configuration of this service. Also, do not use those
# systems as peers for synchronization.
# restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
# IMG1
restrict 10.129.55.30 mask 255.255.255.0 nomodify notrap
# --- OUR TIMESERVERS -----
# or remove the default restrict line
# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
# restrict mytrustedtimeserverip mask 255.255.255.255 nomodify notrap noquery
# server mytrustedtimeserverip
# --- NTP MULTICASTCLIENT ---
#multicastclient # listen on default 224.0.1.1
# restrict 224.0.1.1 mask 255.255.255.255 nomodify notrap
# restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
# --- GENERAL CONFIGURATION ---
#
# Undisciplined Local Clock. This is a fake driver intended for backup
# and when no outside source of synchronized time is available. The
# default stratum is usually 3, but in this case we elect to use stratum
# 0. Since the server line does not have the prefer keyword, this driver
# is never used for synchronization, unless no other other
# synchronization source is available. In case the local host is
# controlled by some external source, such as an external oscillator or
# another protocol, the prefer keyword would cause the local host to
# disregard all other synchronization sources, unless the kernel
# modifications are in use and declare an unsynchronized condition.
#
server 127.127.1.0 # local clock
fudge 127.127.1.0 stratum 10
server 66.187.224.4
server 18.26.4.105
server 128.249.1.10
#
# 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
broadcastdelay 0.008
#
# Authentication delay. If you use, or plan to use someday, the
# authentication facility you should make the programs in the auth_stuff
# directory and figure out what this number should be on your machine.
#
authenticate yes
#
# Keys file. If you want to diddle your server at run time, make a
# keys file (mode 600 for sure) and define the key number to be
# used for making requests.
#
# PLEASE DO NOT USE THE DEFAULT VALUES HERE. Pick your own, or remote
# systems might be able to reset your clock at will. Note also that
# ntpd is started with a -A flag, disabling authentication, that
# will have to be removed as well.
#
keys /etc/ntp/keys