iCloud stuff stops working while connected to OpenVPN

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http://serverfault.com – I have a fairly simple OpenVPN setup on an OpenVZ VPS with Ubuntu 11.10. Client is the Viscosity client on Mac OS X 10.8.2, and after some testing, we can rule out the client as being part of the problem. Everything has been working fine except for Apple's iCloud stuff. Web surfing, email, FTP, NNTP, and Skype are all working as expected. It's ONLY the iCloud services that cease to function. If I connect to the VPN, iCloud stuff stops working. I no longer get anything in Messages, Calendar items don't get updated, and Notifications stop working. If I disconnect, the iCloud stuff all starts w (HowTos)