Accessing File Services

One of the strengths of Mac OS X is its ability to easily access networked file services provided by a variety of different operating systems. In addition to accessing Mac OS X Server computers, Mac OS X is able to access files stored on Windows and UNIX file servers and allow applications to work with the files on the servers as easily as working with files stored on local volumes. This allows Mac OS X computers to be integrated into mixed-computer networks.

Using Connect to Server

The Finder is the primary application used to access files, including those stored on file servers. To connect to these servers, begin by choosing Go > Connect to Server (Command-K).

When you choose Connect to Server, the Finder prompts you for an address. You can use an IP address, DNS name, or local hostname for the server to which you want to connect. The prefix to the address tells Mac OS X which file sharing protocol to use. When you connect to a shared volume in this manner, the volume is mounted in /Volumes and appears on the desktop and in the Finder with other network and local volumes.

In addition to manually mounting a network volume, you can configure your user preferences to automatically mount a shared volume. Once the shared volume is mounted on the desktop, open Accounts preferences, select the user account, and click Login Items. The Login Items pane lists items that will open automatically when the user logs in (the list may be empty). Drag the icon for the shared volume from the Finder desktop into the list, and verify that the volume name is listed. The next time that user logs in, the volume will be mounted. (The user may be asked to authenticate if the password was not saved to the user's keychain when the volume was originally mounted.)

To unmount a shared volume, either drag it to the Trash (which changes to an Eject icon) or choose File > Eject (Command-E). Either action effectively breaks the connection with the shared resource.

If you are connected to a network volume and the server or network goes down, the volume will remain listed in the Finder. If you attempt to access an unreachable server, the spinning cursor will appear as the Finder attempts to reconnect to the server. If it is unsuccessful, it will remove (unmount) the volume.

Using Connect to Server, you can connect to the following types of servers:

Apple Filing Protocol (AFP)
Server Message Block (SMB)
WebDAV
Network File System (NFS)
File Transfer Protocol (FTP)

The following sections explain how to connect to the various types of servers. Since few readers have access to a computer with all types of servers, you are not expected to actually perform these step-by-step instructions. Simply read along to understand the procedures.

Apple Filing Protocol (AFP)

The file sharing protocol most commonly used in Mac OS X is Apple Filing Protocol (AFP). This protocol allows you to mount volumes from computers running Mac OS 9 or earlier, as well as computers running Mac OS X.

These steps demonstrate the process of using Connect to Server to mount an AFP volume.

1.	Choose Go > Connect to Server (Command-K). The Connect to Server window appears.
2.	In the Server Address field, enter afp:// followed by the server's IP address, DNS name, or local hostname, optionally followed by a trailing slash. NOTE Connect to Server assumes that you want an AFP volume if you do not specify a protocol.
3.	Click Connect.
4.	When prompted, specify that you want to connect as a registered user, then enter a user name and password for an account on the server. NOTE If the account doesn't have a password, you won't be prompted for one.
5.	Click Connect. A list of shared volumes to which you have access appears.
6.	Select the volumes you wish to mount (Shift-click to select more than one), then click OK. The shared volumes appear in the Sidebar at the left of the Finder window. NOTE Previous versions of Mac OS X supported AFP connections using AppleTalk networking, but Mac OS X 10.4 does not.
7.	Select the mounted volume(s) and begin dragging them to the Trash. As you begin to drag the volumes to the Trash, the Trash icon changes to the Eject icon. You can also eject volumes by selecting them and choosing File > Eject (Command-E) or by clicking the eject button next to the volume name in the Sidebar.

Server Message Block (SMB)

Another common file sharing protocol is Server Message Block (SMB). Computers running Microsoft Windows use this protocol to share files. Use it on Mac OS X to access files shared by computers running Windows.

These steps demonstrate the process of using Connect to Server to mount an SMB volume.

1.	Choose Go > Connect to Server (Command-K). The Connect to Server window appears.
2.	In the Server Address field, enter smb:// followed by the server's IP address, DNS name, or local hostname, optionally followed by a trailing slash. NOTE When browsing for SMB servers in the Connect to Server browsing window on a network where DNS provides reverse lookups, the domain name will be displayed instead of the computer name. For details, refer to Knowledge Base document 107085, "Mac OS X 10.2: Expected, User-Defined Windows (SMB) Computer Name Does Not Appear in Connect to Server Dialog."
3.	Click Connect. The SMB Mount dialog appears. A Connecting to Server status dialog also appears.
4.	In the SMB dialog, from the "Select a share" pop-up menu, choose the desired item. Shared items are sometimes called share points, because you don't necessarily have to share an entire volume. You can choose to share only a particular folder on a volume, if you wish.
5.	Click OK. The SMB/CIFS (Common Internet File System) Filesystem Authentication dialog appears.
6.	Enter the workgroup/domain, user name, and password for an account on the server. The administrator of the Windows computer can provide you with the name of the workgroup. The default name is WORKGROUP. NOTE SMB won't let you log into an account without entering a password. For accounts with no password, the user can enter anything.
7.	Click OK. The shared volume appears in the Sidebar at the left of the Finder window.

NOTE

New in Mac OS X 10.4 is the ability to authenticate to Windows servers using NT LAN Manager version 2 (NTLMv2). NTLMv2 provides the most secure way of authenticating for Windows computers and is the default authentication method on Windows Server 2003. Support for NTLMv2 from Mac OS X 10.4 means that Mac clients can connect to Windows servers without requiring a Windows administrator to enable a less secure authentication method for Mac clients.

WebDAV

WebDAV is an extension of the Hypertext Transfer Protocol (HTTP), typically used for editing web content. (This is the same protocol you use when you access pages on the web with a browser.) With WebDAV, however, you mount the website as a volume, and you can add and modify files as well as read them.

These steps demonstrate the process of using Connect to Server to mount a WebDAV volume.

1.	Choose Go > Connect to Server (Command-K). The Connect to Server window appears.
2.	In the Server Address field, enter http:// followed by the server's IP address, DNS name, or local hostname, optionally followed by a trailing slash.
3.	Click Connect.
4.	If a WebDAV File System Security Notice appears, click Continue.
5.	If prompted, enter a user name and password for an account on the server, then click OK. The shared volume appears in the Sidebar at the left of the Finder window.

NOTE

New in Mac OS X 10.4 is the ability to connect to WebDAV servers using the secure HTTPS protocol. To connect to a secure WebDAV server, specify the address using the prefix https, such as: https://secureserver.pretendco.com. You can use Get Info to see if a volume is mounted via HTTPS by looking at the server URL under the General disclosure triangle.

Network File System (NFS)

NFS is the file sharing protocol used by most UNIX systems. NFS servers are not considered as secure as other file servers, such as AFP, because NFS authorizes access based on the computer's IP address, rather than prompting a user for a name and password. Because it is easy for a user to change a computer's IP address, it is extremely easy for a computer to pose as an authorized computer to gain access to the NFS server.

These steps demonstrate the process of using Connect to Server to mount an NFS volume.

1.	Choose Go > Connect to Server (Command-K). The Connect to Server window appears.
2.	In the Server Address field, enter nfs:// followed by the server's IP address, DNS name, or local hostname, optionally followed by a trailing slash.
3.	Click Connect. The shared volume appears in the Sidebar at the left of the Finder window.

File Transfer Protocol (FTP)

FTP is important primarily because it is widely used on the Internet for transferring files. Most UNIX-like operating systems provide FTP services, and FTP clients are available for nearly every computer operating system; Mac OS X is no exception in either regard.

These steps demonstrate the process of using Connect to Server to mount an FTP volume.

1.	Choose Go > Connect to Server (Command-K). The Connect to Server window appears.
2.	In the Server Address field, enter ftp:// Discovering File Services followed by the server's IP address, DNS name, or local hostname, optionally followed by a trailing slash.
3.	Click Connect.
4.	When prompted, enter a user name and password for an account on the server. NOTE FTP won't let you log in to an account without entering a password. For accounts with no password, the user can enter anything. FTP transmits all data, including the user name and password, in the clear, and is not a secure method of exchange.
5.	Click OK. The shared volume appears in the Sidebar at the left of the Finder window.

NOTE

In Mac OS X, you can download files after mounting an FTP volume using Connect to Server, but you cannot upload files over FTP using the Finder. Uploading files to an FTP server can be accomplished only with an FTP client such as Fetch (www.fetchsoftworks.com) or Transmit (www.panic.com).

Dealing with File Sharing Protocol Issues

Usually, the protocol you need to use is dictated by the server to which you are connecting. Even though you may not have a choice, you should be aware of issues that can arise when using the different protocols.

Files with resource forks As explained in Lesson 4, "File Systems," Mac OS X files can have a resource fork in addition to the traditional data fork. Just as nonApple file systems such as UFS and FAT don't support files with resource forks, file sharing protocols other than AFP do not either. To compensate, Mac OS X will send the resource fork out as a separate file with a prefix of period and underscore (for example, ._TestFile.pdf), just as it does when writing to non-Apple file systems. Because Mac OS X handles the conversion between resource forks and ._ files automatically, you will not see the files in the Finder. However, users on other operating systems such as Windows will see two separate files.
Windows servers To provide file sharing for Macintosh clients, some administrators have configured Services for Macintosh (SFM) on their Windows NT servers to provide AFP access. Unfortunately, SFM does not provide full AFP 3.1 support. In addition to the problems managing resource forks, SFM is also limited to 65,000 files on a volume. Whenever possible, use a server that fully supports AFP 3.1, such as Mac OS X Server. For Windows servers, you can use third-party AFP servers such as Group Logic's ExtremeZ-IP (www.grouplogic.com).