updated 12:20 am EST, Fri January 31, 2014
Access Bonjour services from a home location while on the road
Apple's zero-configuration Bonjour networking protocol is awfully convenient. On a single subnet, it allows an OS X machine or a properly-configured Windows computer to easily identify and access assets on that network -- file servers, other computers, printers and the like. The only problem with Bonjour is by itself, Bonjour-configured devices and services have no accessibility across the Internet. A solution is developer Yazsoft's ShareTool 2 for Mac -- what the company itself calls a "fast, extremely secure, and magical way to remain connected to your home or office."
The list of features that ShareTool purports to allow are: encryption of remote web traffic routed through a home network (proxy browsing); remote listening of the home's iTunes library; iTunes Home Sharing fully supported across the Internet; remote access of any of the home network's computer; FileMaker Pro database access, iPhoto library access, and more. Some of these features, like iTunes and iPhoto access, have been subsumed in full or in part by Apple features such as iTunes Match or Back to My Mac since ShareTool's original release a few years ago, but at a cost in usability or for an actual fee, as is the case with iTunes Match.
Both the remote Mac and the home Mac must have ShareTool installed -- the normal purchase option for the app is a pair of licenses for $25 with additional licenses for $15 each, so this isn't an issue. Importantly, none of the other services on other computers on the home network using Bonjour need ShareTool, only the single bridging Mac.
Security for the transfer uses OS X's integrated OpenSSH implementation, which by default uses AES-128 encryption for all communications. The app pair prefers a home router which uses UPnP for automatic port routing, but if unavailable, the bridging Mac on the network can be configured with a static LAN IP in conjunction with manual port-forwarding configuration on the router to allow access anyway. Unfortunately, in a scenario with no router Admin access, the latter configuration isn't possible. Importantly, though, only the home network router needs to be accessible by the user, not the remote location.
There are a few caveats with ShareTool. Generally, the home Mac must be running (and not sleeping) for ShareTool to work properly. However, if the home Mac is running OS X 10.6 or later, and connected to an Airport Base Station or Time Capsule running relatively modern firmware, then the home computer can be set for "wake for network access" in the Energy Saver preference pane, to save on energy usage. Apple computers that support this functionality are some 2008 models, and everything from 2009 and up.
Sharetool isn't bi-directional. Practically, this means that two networks cannot be bridged with members of the home network being able to see Bonjour services on the remote network -- only vice versa. For its intended and stated use, this isn't an issue, but it is worth noting. The Yazsoft developers claim to be considering the feature for a future update, however.
I have been using ShareTool for nearly four years, in conjunction with our home server and an assortment of laptop computers. With few exceptions (mostly related to the occasional overloaded public hotspot), it has worked in hospitals, coffee shops, libraries, and other public access points flawlessly with my (admittedly high-speed) Verizon FIOS home connection. Overall performance has increased, as my home Internet speed has accelerated over the years -- but even with the original release and a 10 mbit upstream connection in 2008, I still had no problems doing anything I needed to do, including the sometimes bandwidth-punishing remote access while moving files back and forth.
ShareTool doesn't do everything. There is no iOS access provision. No Windows version of ShareTool exists. As previously mentioned, Wake on Network is limited to Apple Airport base stations. Configuration couldn't be simpler, however, and those with even a modicum of network know-how can properly install and use the tool, spreading the value of Bonjour services securely across the Internet.
Who is ShareTool for?
Road warriors needing routine access to files stored at a "home" location.
Who is ShareTool not right for?
People needing to bridge two Bonjour-provisioned networks.