Web Sharing and WebDAV

Because Windows 2000 is a complex product that includes many integrated components, several of its features remain relatively unknown. One such feature is Microsoft Internet Information Services’ (IIS's) WWW Distributed Authoring and Versioning (WebDAV). (IIS 5.0 is included with Win2K Server.) Based on Request for Comments (RFC) 2518, WebDAV extends HTTP functionality so that you can work collaboratively with shared files over the Internet. Since its inception, the Internet has provided a great way to share access to read-only information, but WebDAV lets you use the Internet to give write access to files, providing a platform to create document-management and collaborative applications.

WebDAV
Configuring a Win2K-IIS 5.0 machine to use WebDAV is straightforward. Right-click a folder that you want to share access to and choose Properties. Select the Web Sharing tab, and select Share this Folder. On the Edit Alias dialog box that appears, create an alias for the shared WebDAV folder. The alias name you specify will become the name of the virtual directory that the system creates and will appear in the Microsoft Management Console (MMC) Internet Services Manager (ISM) snap-in.

From a Win2K machine, you can connect to WebDAV folders by opening My Network Places and specifying the folder's URL (e.g., http://www.win2000mag.com/web_docs) instead of the usual Universal Naming Convention (UNC) path. From other OSs, you can connect to WebDAV folders using Microsoft Internet Explorer (IE) 5.0 or later. Open IE, click File, Open, and specify the URL. Next, select Open as a Web Folder.

Once you've established a connection to a WebDAV folder, you can manipulate folder resources just as you would if you were working with a local folder. If you have the appropriate permissions, you can add files and modify existing files, for example. Best of all, because you connect to WebDAV folders through HTTP, you can work with the folder from virtually anywhere. This flexibility gives you new options for supporting remote users and widely dispersed project teams. You can use Microsoft Office's revision tracking features to extend the functionality even further.

WebDAV might seem similar to FTP, but a few differences exist. When you work with WebDAV folders, the files you're accessing remain in those folders. With FTP, you download files to your local machine, make changes to those files, and transfer the files back to the FTP server, overwriting the original files. However, when you make changes to a file in a WebDAV folder, the system places a lock on the file so that other users can't make changes to it. Other users can still view the file, but only one user can make changes at a time. Also, WebDAV provides more security than FTP because of HTTP's more secure authentication and encryption features (e.g., Secure Sockets Layer—SSL).

Securing WebDAV Resources
You control security access to WebDAV folders at two levels. First, when you enable a folder for Web sharing, you can specify whether to permit read or read/write access and whether to permit directory browsing. Directory browsing lets users see the files that exist in shared folders. Second, you can set NTFS permissions on the WebDAV folder to specify which users have access to the folder. Remember that for NTFS permissions to be effective, you must configure authentication control. You can configure authentication control by opening the ISM snap-in and accessing the virtual directory properties.

As a final note, if you grant write access to many users, consider configuring disk quotas on your Web server. Disk quotas will prevent users from copying a large number of files to your Web server and consuming too much hard-disk space.