Requirements to use Back to My Mac An AirPort Extreme or Express base station, or third-party Internet router, which supports UPnP or NAT-PMP (see here), with the latest available firmware installed (version 7.4.1 or later for AirPort). A MobileMe subscription. Two or more Mac OS X v10.5 Leopard-based Macs that are configured to use the same MobileMe account (Mac OS X v10.5.6 or later is strongly recommended). Screen sharing requires a 300-Kbps, or faster, bi-directional Internet connection (up/down) between the computers. (File sharing may be usable with slower connections)Note: Some firewalls, such as at a large organization, may not allow some Back to My Mac connections. For example, you might not be able to contact your Mac at work from home, but you might be able to contact your Mac at home from work. Check with your organization's network administrator.See this article for detailed information about security and Back to My Mac.
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