I’m sometimes amazed at how many large organizations don’t have a centralized Network Time Protocol (NTP) server setup and devices configured appropriately. When troubleshooting a problem it’s vital that the timestamps in the logs for each switch, router, server and appliance match up correctly.
I’m currently using two CentOS Linux servers to provide time services to over 10,000 devices in the network. My two servers are themselves syncing up with pool.ntp.org over the Internet. With CentOS I didn’t need to build the software, I only needed to install the NTP package through YUM and then configure it appropriately. It was really easy, much easier than it was say 10 years ago when you had to compile the NTP software (University of Delaware) by hand hoping you didn’t run into some missing library of version mismatch with the compiler.
We would first need to install the NTP software using YUM;
[root@hostname ]# yum install ntp
We would need to start the NTP daemons;
[root@hostname ]# service ntpd start
We would need to configure the server so the NTP software would start after every reboot;
[root@hostname ]# chkconfig ntpd on
With that step done we’d have ourselves and internal NTP server which would sync itself to the Internet (default configuration file in /etc/ntp.conf) and then our internal devices would sync to it.
Here are the CLI commands for configuring the ERS 8600 switch properly;
config bootconfig tz dst-name "EDT" config bootconfig tz name "EST" config bootconfig tz offset-from-utc 300 config bootconfig tz dst-end M11.1.0/0200 config bootconfig tz dst-start M3.2.0/0200 config ntp server create a.b.c.d config ntp server create a.b.c.d config ntp server create a.b.c.d config ntp enable true
I’ve add the two configuration statements for the new Daylight Saving Time changes that were enacted in 2007. Please also note that I’m in the Eastern timezone (EDT/EST) so if you’re not in the Eastern timezone you would need to supplement your timezone abbreviation appropriately.
Here are the commands for an ES460,ES470,ERS4500 or ERS5500 series switch
5520-48T-PWR# config terminal 5520-48T-PWR (config)# sntp server primary a.b.c.d 5520-48T-PWR (config)# sntp server secondary a.b.c.d 5520-48T-PWR (config)# sntp enable 5520-48T-PWR (config)# exit5520-48T-PWR#
The ERS 4500/5500 Series now supports Daylight Saving Time. This feature is NOT supported on the ES460 and ES470 switches. –-CORRECTION: this feature is support on the ES460/470 as of v3.7.x software, please see update at the bottom of this post for additional information. If you wanted to configure the timezone on the ERS4500/ERS5500 switch you would use the following commands;
5520-48T-PWR>enable 5520-48T-PWR# config terminal 5520-48T-PWR (config)# clock time-zone EST -5 5520-48T-PWR (config)# clock summer-time EDT date 9 Mar 2008 2:00 2 Nov 2008 2:00 +60 5520-48T-PWR (config)# exit 5520-48T-PWR#
You can use “show sntp” and “show clock” the ERS 5500 Series switch to check out your changes;
5530-24TFD#show sntp SNTP Status: Enabled Primary server address: 10.1.20.1 Secondary server address: 10.1.20.1 Sync interval: 24 hours Last sync source: 10.1.20.1 Primary server sync failures: 0 Secondary server sync failures: 0 Last sync time: 2008-06-14 14:47:31 GMT-04:00 Next sync time: 2008-06-15 14:47:31 GMT-04:00 Current time: 2008-06-15 13:52:24 GMT-04:00 5530-24TFD#show clock Current SNTP time : 2008-06-15 13:52:29 GMT-04:00 Summer time is set to: start: 28 March 2007 at 02:00 end: 30 August 2008 at 15:00 Offset: 60 minutes. Timezone will be 'EDT'Time Zone is set to 'EST', offset from UTC is -05:00
Hopefully this will provide a brief look into NTP,SNTP and you’ll agree that it really isn’t that hard to setup and configure properly.
Update: June 17, 2008
After posting the article above I decided I would confirm that the Daylight Saving Time feature was not available on the Nortel Ethernet Switch 460/470. I found that as of v3.7.x software the feature is supported on the switches. The configuration commands are identical to the ERS4500/ERS5500 switches. Here’s an example specifically for the Eastern timezone.
470-48T>enable470-48T#config term Enter configuration commands, one per line. End with CNTL/Z. 470-48T(config)#clock time-zone EST -5 00 470-48T(config)#clock summer-time EDT date 9 Mar 2008 02:00 2 Nov 2008 2:00 +60 470-48T(config)#show clock summer-time Summer time is set to:start: 9 March 2008 at 02:00end: 2 November 2008 at 02:00 Offset: 60 minutes. Timezone will be 'EDT' 470-48T(config)#exit