Recommendations for NTP configuration for virtual machine installations
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Recommendations for NTP configuration for virtual machine installations


Article ID: 174700


Updated On:


Messaging Gateway


  • Symantec Messaging Gateway (SMG) installation needs to use NTP for time sync.
  • SMG is installed on Hyper-V or VMWare virtualization host


  • SMG (any version)
  • Virtual host
    • VMWare ESX(i)/VSphere
      • or
    • Microsoft Hyper-V




Symantec recommends

  • using NTP hosts that exist on local network
  • disabling time sync in the VM host

Note: If internal NTP hosts are not an option, external NTP hosts/pools can be used, but not recommended for long term solutions.

Disable time syncronization in VM host

Symantec, Microsoft, and VMWare recommend time sync to be disabled in the VM host, and the guest OS/server (SMG in this case) control the system clock.

For VMWare, see the "VMware Tools Time Synchronization and Configuration" section of Timekeeping best practices for Windows, including NTP (1318) by VMWare.

For Hyper-V (per

  1. Shut down virtual machine.
  2. Open Hyper-V Manager.
  3. Right click on the VM in question, and select "Integration Services".
  4. Uncheck "Time Syncronization".
  5. Click Apply.
  6. Restart VM.

Configure NTP in SMG

  1. Go to Administration > Hosts > Config > server > DNS/Time tab.
  2. Click on "Use NTP servers" radio button.
  3. Enter NTP hosts to be used. Priority diminishes down the list.
  4. If all SMG hosts will use the same DNS and NTP servers, check "Apply above settings to all servers".
  5. Click Save.
  6. If step 4 is not performed, repeat for each SMG host.