Back to My Mac is just one way to gain remote control of your Mac. Timbuktu Pro, LogMeIn, and Apple Remote Desktop are three others I'd recommend for particular purposes. In this section, I look at each of these products in turn.
Netopia's Timbuktu Pro (often abbreviated as TB2 by those in the know) is a full-featured remote control and administrative tool (Figure A-1). TB2 is widely used across Windows and Mac OS X systems in corporations and academia (http://www.netopia.com/software/products/tb2).
Figure A-1. Timbuktu's New Connection window shows its range of support for stored entries, Bonjour-linked computers, dial-up (!), Skype, direct IP connections, and its own form of network discovery.
The software combines both client and server features in one package. You need at least two copies of TB2 to make a connection: one on a target machine, running as a server; the other on the connecting computer, using the client interface (shown above). You can choose not to enable incoming access on a computer that you want to use only as a client (to connect to other remote systems).
TB2 has two substantial flaws for use outside large organizations:
High cost: It's expensive. The downloadable version starts at $94.95 for a single license, but you need at least two copies to make a connection. A 2-system license is $179.95, 10 licenses run $629.95, and 30 are $1649.95. That pencils out to $55 per copy when you buy 30 at once. Prices are about 10 percent higher for multi-platform bundles.
No NAT: TB2 can't reach through NAT on its own. The NAT problem is more substantial than the cost problem. Timbuktu Pro, even in its 8.7 version for Mac OS X, doesn't talk to NAT-PMP or UPNP, so even if you have a publicly routable IP address on your router, you can't use TB2. But, see the note below for a possible solution.
However, it's not a simple choice of TB2 versus Back to My Mac: TB2 is designed for a user of one system to securely access many different computers, including any mix of Windows and Mac OS X releases, with specific controls that let you set what kind of access is granted for each user on each computer. It potentially allows you to transfer files, handle voice calls and text messaging, and perform a bunch of system-administration tasks. In contrast, Back to My Mac is about one user accessing a handful of Macs, with similar access to all those Macs and no per-Mac cost; just a yearly $100 membership with .Mac (which brings other services and benefits, too).
THE SKYPE WORKAROUND
Netopia added a way around Timbuktu's NAT limitation that I've found useful, but not perfect in practice: they take advantage of Skype's awesome NAT traversal, which seems to allow Skype to work nearly everywhere, even when firewalls should prevent it.
This feature, which first appeared in TB2 8.6 for the Macintosh, requires a logged-in Skype user at each location. The controls allow each remote user to grant specific access permission to a Skype user when access is requested. In typical use, the amount of network workarounds that are required to make a connection between two computers using TB2 over Skype also makes remote access seem very sluggish compared to a direct connection between the same two computers. But it does work. Skype, at least, is free.
For more details, see http://www.netopia.com/software/products/tb2/tb2_skype.html.