02-07-2008 08:35 AM - edited 03-05-2019 09:01 PM
I have a cisco 6506 switch running IOS 12.2 release.I want to configure this switch as ntp server.Pl help how to configure
02-07-2008 09:27 AM
Configuration is pretty simple:
ntp server 192.168.11.13
ntp server 192.168.1.26
To verify it's working, try the following:
CORE1#show ntp associations
address ref clock st when poll reach delay offset disp
*~192.168.11.13 129.7.1.66 2 35 64 377 -0.0 18.46 2.1
+~192.168.1.5 192.168.11.13 3 35 64 377 -0.0 16.66 2.0
+~192.168.1.26 192.168.11.13 3 11 64 377 -0.0 18.78 0.3
* master (synced), # master (unsynced), + selected, - candidate, ~ configured
CORE1#show ntp status
Clock is synchronized, stratum 3, reference is 192.168.11.13
nominal freq is 250.0000 Hz, actual freq is 240.5256 Hz, precision is 2**18
reference time is CB55BD1D.75C290A0 (11:23:41.460 CST Thu Feb 7 2008)
clock offset is 18.4639 msec, root delay is 40.62 msec
root dispersion is 87.45 msec, peer dispersion is 3.31 msec
CORE1#
If you connect to an NTP server on the outside, make sure you open the port on the firewall (UDP 123).
HTH
03-16-2015 03:56 AM
Can a ios device which is currently acting as NTP server for the network be pointed to a dedicated NTP server and still act as NTP server.
Current config
ntp source Loopback0
ntp master
ntp update-calendar
ntp master 7
New config.
ntp source Loopback0
ntp master
ntp update-calendar
ntp master 7
ntp master x.x.x.x prefer
ntp master x.x.x.x
The reason for the change is UC call managers have a time lag because of that IP Phones and Domain PC have different time display also these UC call Managers have license hard coded based on this NTP servers and if a change in that will lead to a license rehosting.For that I have planned to retain the existing IOS NTP Routers as master but make them fetch the Time from a different dedicated NTP server instead of using the internal clock.
03-16-2015 05:41 AM
Especially since you have specified that your IOS device is stratum 7 there should be no problem in pointing it to an authoritative NTP server at a higher stratum and having your device learn time from the higher stratum server.
HTH
Rick
02-09-2008 12:49 AM
Hi,
If you want to make the Core6506 as ntp master, then u need to add the command "ntp master" and set the time zone " clock timezone GMT +X". This switch will become as master for other switches. On edge switch configure "ntp server x.x.x.x (ip of 6506).
rate this if it helps..
*aijaz*
02-09-2008 02:41 AM
Hi Kaushik,
To treat a Cisco device as a NTP Server, you can do the following:
SW(config)#ntp master ( Act as NTP master clock )
SW#clock timezone GMT + (Ur Local time zone)
And if you want to make a Device that learn the NTP clock from a NTP Master, u can do the following:
#ntp source (physical/logical_IP_Address)
#ntp server x.x.x.x (ip address of Master Device)
Thanks
Goutam
Pls rate if its works
02-09-2008 03:47 AM
Mr. Kaushik,
I hope these configs are sufficient for running NTP in your network, but, if you are stil facing the problem kindlly let us know the topology in between your master and slave (NTP). Besides you can configure "ntp source Loopback0" for more stable time-sync. This will have source IP of the NTP packet as 'loopack address' of the communicating device, if you have configured the loopback at your device.
--gaurav
02-09-2008 04:31 AM
02-09-2008 04:55 AM
Several of the posts have suggested configuring the 6506 as ntp master. While this is certainly possible I believe that it is not such a good idea, unless the switch has some really accurate time source that is locally connected.
If the 6506 is learning time from some NTP server then it will server NTP time to any other device in its network without needing the ntp master configuration. The key concept is whether the switch believes that it has authoritative time. If it is learning time from an ntp server then it is authoritative and if it is configured as ntp master then it is authoritative. And if it is authoritative then it will serve NTP time to other devices.
If the switch is learning time from an NTP server then it should be quite accurate. If the switch is not learning time from an NTP server then it relies on its own internal clock. While the internal clock is pretty accurate in human terms it is not so very accurate in NTP standards. It is much better for the switch to learn time from an NTP server (or from 2 or 3 for redundancy) than it is to rely on its own clock.
HTH
Rick
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