NTP Server

Could someone help me with the details of setting up my server as a NTP server to pass the time to my routers and switch? I have Virtual-min installed. I performed a search on NTP and the search came up with setting the configurables of the NTP server, Time zone, Set time, and Time sync.

I have a suspicion that my server is not sending ntp packets to my devices, but only getting ntp packets for setting the server time.

Thank You,


NTP is a daemon process that runs on your server. It doesn’t actually push out the time to systems such as your routers, those systems have to perform a query for the time.

So, once you’ve setup NTP on your server, what you’d need to do is configure your routers and servers to poll your NTP server, and retrieve the time from it.


Hi Andreychek, you and i have been here before, LOL. You have always answered my problems, Thanks!!!

My Cisco routers and switch have been configure to accept packets from the NTP server at and if I run a “show ntp ass” command from the devices, they show that indeed they are synced and receiving NTP packets from the DMZ server. Unfortunately with the recent time change, the time on the server is correct but the devices on the LAN are an hour ahead.

I will look in more depth on what i need to provide the routers and switch that will poll the NTP server and receive the time from it. My problem might be due to an access-list issue. In any case i will post a solution when i discover it. Thank You!



It might help you to know that NTP uses UDP port 123 (by default), and under Linux you can use the command “ntpdate” to sync the system to an NTP server. This is what Webmin sets up when you use its Hardware -> System Time section. In addition to that, you can also install the full ntpd (which besides offering time service can also fetch the time from another time server) on the client.

And I got a question too concerning this. :slight_smile: A rather Webmin-internal one:

When I set Webmin to regularly update my system time through ntpdate, how exactly is that achieved? I could not find an entry in the crontab that matches the time I set…

If I remember correctly, I believe I recall Jamie saying that Webmin/Virtualmin actually calls out to ntpdate itself, rather than putting that in cron.

It looks like that’s probably done via the “sync_time” function in /usr/share/webmin/virtual-server/time/time-lib.pl, in case you wanted to take a peek :slight_smile:


Great Eric thanks for info! :slight_smile: