Peer-to-Peer File Sharing in OS X

It got a bad rap with software like Napster and Kazaa that allows users to illegally download MP3s. But peer-to-peer networking ( P2P) in Apple's Mac OS X means that users on your network can share files and folders in order to work together more efficiently, and you won't have to spend the money and resources to set up a standard centralized server.

Share the Love

OS X includes support for cross-platform peer-to-peer file sharing right out of the box. This includes standard AppleShare ( AFP) protocol and Windows file sharing ( SMB protocol) via the Samba file serving system.

By default, peer-to-peer file sharing is turned off. To activate it, open System Preferences, click "Sharing," select "Personal File Sharing," and click the Start button. This turns on the Appleshare system and shares the Public folders in each user’s home directory, as well as the Shared folder in the Users directory. Selecting and starting "Windows Sharing" activates the Samba software and shares the Public folder and shared folder with Windows clients on the local network.

Creating a Peer-Server with Sharepoints

Even though the software that runs the file sharing on OS X client computers is very similar to the software on OS X Server, it has a few key differences. First, the file sharing software has a limit of 10 concurrent users, which can limit its usefulness on larger networks, and second, the configuration options available via the standard OS X interface are very limited. In fact, if you're used to OS 9, you'll find that many features you've grown accustomed to on the old Mac operating system are gone. Blame it on the OS X's new Unix base, but you can bring back the share options you miss with another application.

HornWare's Sharepoints , a free software application, adds configuration options to Mac OS X peer-to-peer sharing, allowing a Macintosh OS X client to function as a peer-server. (Note: even on peer-to-peer networks, we have found that it is best to designate one machine as the peer-server, where most, if not all, of the shares are based. This simplifies set-up and maintenance.)

Sharepoints allows you to create shared directories from any file locations, with any set of permissions. It can also allow you to create "share-only" user accounts that can provide users with an account for file access, but not log-on rights.

To use Sharepoints, download the latest version for your version of OS X from the Web site. (Your OS version is shown in the "About This Mac" window, accessible via the Apple menu.) Sharepoints is available as a stand-alone application and as a preferences pane. To install the preferences pane, just double-click, and it will install itself in the System Preferences panel. The Sharepoints application will operate from any location. A good overview of all of Sharepoints’ options is available from OSXGuide.com .

The Sharepoints interface consists of five panes: "Normal Shares," "Users & Public Shares," "Groups," "AFS Properties," and "SMB Props."

The "Normal Shares" pane allows you to create shared folders anywhere on your computer’s drives. You can assign any set of permissions to these folders, including group permissions, and you can determine whether to use Apple file sharing ( AFS), Windows file sharing (SMB), or both.

The "Users & Public Shares" pane allows you to monitor individual shares, as well as create share-only accounts. The "Groups" panel allows you to create and delete user groups -- which allow you to specify a single set of permissions that apply to multiple accounts -- and add and remove users from groups.

Once you’ve created a share and set up users and groups, you should be able to access the shares from other computers on the network. Keep in mind that the user accounts you create using Sharepoints are not the same as the accounts people use to log on to their local machines, so users may need to enter a new username and password, as the user name and passwords can be different. For Sharepoints to work smoothly it is important to put some effort into coordinating and documenting user account set-up on both client machines and the Sharepoints server.

Share and Share Alike

So, how can you put these shares and fancy Sharepoints peer-server to use in your organization? Pretty much any way you want. Some possibilities include:

• a share with read-only rights, for document distribution
• a share with read and write privileges for everyone, useful as a "temp folder" for the network
• shares with permissions limited to specific groups of users, for program-specific file sharing (for example, financial documents).

If a number of different shares have the same permissions, it might make more sense to combine them into one single share with multiple sub-folders.

The most important aspect of setting up shares is planning. Figure out what shares need to be set up with which permissions. Make sure share names make sense to the users, so they know where to put files -- and more importantly -- where to find them. Carefully think about the file structure and how the organization classifies information. The more planning and forethought that you put into the sharing set-up, the more useful it will be to the organization and the easier it will be to maintain.

For more information on organizing a file server, read the article Taming Your File Server". .