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I have Ubuntu Server running as a guest on a Windows host using VirtualBox 3. The Ubuntu Server has guest additions installed.

To save a bit of time when I use this image, I suspend rather than shutting down. This works fine except for the date of the clock on the guest machine.

Is there a command I can run on the guest once it has been restored to force it to set the clock from the underlying host?

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up vote 1 down vote accepted

If you route Internet connection to the guest OS, you may use ntpdate to sync it's clock with special time servers, e.g.

sudo ntpdate
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I'm afraid that won't work for me because of the nature of my setup (ntpdate isn't installed on the machine and no regular internet access). That's why I took the trouble to install Guest Additions, so that the guest could get at the host's clock. Sadly it seems to only access it on a full initialisation of the client VM - rebooting the client OS isn't good enough. – Rich Jan 19 '11 at 15:31

My apologies for bumping a 1,5 year old question which is, in my opinion, partly answered.

Since you have a windows host, you can make sure you have a ntp server running locally: Then from within your linux client (when running NAT, is the host address) ntpdate

I was looking for the answer myself and found this useful as our firewall blocks the default ntp port.

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