Windows phoning home to Microsoft or what is it?

Is Microsoft phoning home or what is it? I get these popups once or twice daily.
Pic:
http://i13.tinypic.com/6l443dv.jpg

Thanks.

-polo-

 

Port 123 is NTP or Network Time Protocol. That's how Windows syncs the system clock with the atomic clock.

 

You probably have already allowed the outbound traffic for W32Time via Svchost, now the firewall is asking you if you want to allow the resulting reply from the NTP server. If you want your clock sync'd then you need to allow the inbound return traffic also.