FreeBSD use the Network Time Protocol (NTP) for synchronizing the clocks of computer systems over packet-switched, variable-latency data networks. NTP uses UDP port 123. If you have one computer or single server then you can easily synchronization time with other NTP servers. All you need is ntp client called ntpdate. It is use to set the date and time via NTP servers.
FreeBSD: Install NTP Client
Use any one of the following command to install NTP:
# pkg_add -rv ntp
OR
# cd /usr/ports/net/ntp # make; make install
Pick appropriate NTP Servers
Visit public ntp timeserver list to pick up your NTP server.
Open UDP port 123 at firewall
If you are running FreeBSD ipfilter firewall, you need to open the UDP port 123. Just add following rule to your firewall script:
pass out quick on lnc0 proto udp from YOUR-SERVER to any port = 123 keep state
OR
pass out quick on lnc0 proto udp from YOUR-SERVER to TIME-SERVER-IP port = 123 keep state
For example, my FreeBSD workstation IP is 192.168.1.16 and 61.246.176.131 is IP of NTP server then my rule is in ipf.conf file as follows:
pass out quick on lnc0 proto udp from 192.168.1.16 to 61.246.176.131 port = 123 keep state
FreeBSD test clock synchronization
Just run ntpdate command as follows to see you can set date and clock via NTP:
Set wrong date (Mon Dec 13 4:27 pm):
# date 0412131627
Now set correct date with ntp client:
# ntpdate -v -b in.pool.ntp.org
13 Dec 16:27:50 ntpdate[997]: ntpdate 4.2.0-a Thu Nov 3 07:34:22 UTC 2005 (1)
25 Jan 12:35:47 ntpdate[997]: step time server 61.246.176.131 offset 35237275.965726 sec
You can verify that correct data is setup:
# date
Output:
Wed Jan 25 12:36:21 IST 2006
Enable date and time/ clock Synchronization at boot time
You need to set ntpdate via /etc/rc.local file.
# vi /etc/rc.conf
Append following line to it:
ntpdate_enable="YES"
ntpdate_hosts="asia.pool.ntp.org"
Save and close the file. Make sure you have correct ntpdate_hosts server entry.
See also:
Updated for accuracy.
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Salamo Alikom
is there any way to prevent gnome changing sys clock ?
Are you sure this is correct?
No, it was a typo and the post has been updated to fix this issue. Thanks for the heads up.
Are you sure this is correct?
# vi /etc/rc.local
and that it’s not rc.conf instead?
i have problem. i can’t configuration & check NTP server.
Help Me. My config:
install /usr/ports/net/ntp
make install
install finish
my server ip address:192.168.0.1/24
1./etc/rc.conf
ntpdate_enable=”YES”
ntpdate_program=”/usr/local/bin/ntpdate”
ntpdate_flags=”-b”
ntpd_enable=”YES”
ntpd_program=”/usr/local/bin/ntpd”
2./etc/ntp.conf
server 0.asia.pool.ntp.org
server 1.asia.pool.ntp.org
server 2.asia.pool.ntp.org
server 3.asia.pool.ntp.org
server 192.168.0.1
broadcast 192.168.0.255
driftfile /var/db/ntp.drift
logfile /var/log/ntp.log
This is one is written on FreeBSD 6.0 but it should work on any version. This entry was written on Jan-25-2006.
Hope this helps.
how can i tell what date the tutorial was written, or what version of of software was used?