Resources used to complete the configuration:

FreeNAS

http://joepaetzel.com/2014/03/03/freenas-naughty-ntp/

 

XenServer

http://support.citrix.com/article/CTX121278
http://support.citrix.com/article/CTX116307

 

NTP

http://www.pool.ntp.org/zone/us
http://support.ntp.org/bin/view/Support/AccessRestrictions#Section_6.5.1.1

 

Windows Server 2012 R2

http://nefaria.com/2013/03/configure-windows-server-20082012-to-sync-with-internet-time-servers/

 

My network consists of 2 FreeNAS servers, and 3 XenServer virtualization servers (which run most of the Microsoft Server 2012 R2 servers, and 2 CentOS 7 machines), and several Windows 7, 8 and 10 clients.

After some consternation, I determined the best course of action was to set up one of the FreeNAS servers to be the primary NTP Server for the network, with the second FreeNAS Server acting as the secondary NTP Server.

Here’s the configuration changes I made to the primary FreeNAS server:

edit: /conf/base/etc/ix.rc.d/ix-ntpd

add the following line towards the end just above the “EOF”:

restrict 10.1.10.0 mask 255.255.255.0 nomodify notrap nopeer

Using the GUI, log in and navigate to System | General, then click on the “NTP Servers” button at the bottom right.

enter the following NTP servers:

0.us.pool.ntp.org
1.us.pool.ntp.org
2.us.pool.ntp.org
3.us.pool.ntp.org

reboot the box

On the Secondary FreeNAS Server, make the following changes:

edit: /conf/base/etc/ix.rc.d/ix-ntpd

add the following line towards the end just above the “EOF”:

restrict 10.1.10.0 mask 255.255.255.0 nomodify notrap nopeer

Using the GUI, log in and navigate to System | General, then click on the “NTP Servers” button at the bottom right.

enter the following NTP servers:

0.us.pool.ntp.org
1.us.pool.ntp.org
2.us.pool.ntp.org
3.us.pool.ntp.org
10.1.10.x –> IP Address of the Primary FreeNAS Server, make this a “Preferred” NTP Server

reboot the box

On each of the XenServer Servers, using XenCenter, log into the console for each and make the following changes:

Using “xsconsole”,

navigate to “Network and Management Interface”
navigate to “Network Time (NTP)”
log in as root
Remove All NTP Servers
Add the Primary FreeNAS Server’s IP Address
Add the Secondary FreeNAS Server’s IP Address
reboot the box

To verify that NTP is working correctly, log into the XenServer console and enter the following:

ntpq –p 10.1.10.x –> the Primary FreeNAS Server, you should get something like this returned:

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+y.ns.gin.ntt.ne 249.224.99.213   2 u   45   64    7   45.388   -2.965   1.896
+104.156.99.226  204.123.2.72     2 u   41   64    7   66.195    5.041   1.599
*clock.xmission. .GPS.            1 u   43   64    7   39.903   -1.483   2.415
time.tritn.com  198.60.22.240    2 u   40   64    7   51.294    1.535   1.984

ntpq –p 10.1.10.x –> the Secondary FreeNAS Server, you should get something like this returned:

     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
+cheezum.mattnor 129.7.1.66       2 u   30  128  377   13.744   -7.718   2.658
+mdnworldwide.co 127.67.113.92    2 u   31  128  377   22.938   -8.589   0.869
-repos.lax-noc.c 206.117.25.20    2 u   41  128  377   50.227   -2.232   2.751
*freeNas.loc.com 198.60.22.240    2 u   73  128  377    0.188   -5.571   1.500
-snotra.fanube.c 132.163.4.102    2 u   66  128  377   54.298    1.640   4.002

 

On the Windows Server 2012 R2 primary domain controller, open a command prompt and enter the following:

 

w32tm /monitor
w32tm /query /status
net stop w32time
w32tm /config /syncfromflags:manual /manualpeerlist:”10.1.10.x, 10.1.10.x”
w32tm /config /reliable:yes
net start w32time
w32tm /query /configuration