Discovering File Services
Mac OS X automatically can find computers and
other devices that offer services on the network. An application
requests the names of available servers, which the operating system
returns. The application, in turn, displays the list in a
user-browsable format. This feature is known as service discovery.
One application that uses service discovery
information is the Finder, which displays a list of computers you
can connect to when you click Network in the Sidebar of a Finder
window. You connect to a discovered resource by clicking Connect under the volume icon (in column view)
or double-clicking the volume icon. You will be prompted to
authenticate with a user name and password of an account on the
file sharing server.
While service discovery can be used by a variety
of applications, such as Printer Setup Utility and iChat, this
lesson will focus on using the Finder to discover file servers.
Printer discovery will be covered later in Lesson 12, "Printing."
A network can be broken up into logical sections
called zones. Usually zones are created to group-related networked
resources, such as all of the servers and printers for the
marketing department. Each zone is presented as a separate folder
when you select the Network icon from the Sidebar in the
Finder.
Understanding Dynamic Service
Discovery
Dynamic service discovery protocols reflect the
current state of the network, because they update whenever new
services appear or disappear on the network. The protocols usually
work without needing a dedicated server.
Mac OS X includes support for four dynamic
service discovery protocols:
-
Bonjour (previously
called Rendezvous) is Apple's implementation of an emerging
industry standard called Zeroconf. Bonjour provides service
discovery functionality for IP-based networks using standard IP
protocols. Bonjour is always enabled in Mac OS X 10.4.
-
AppleTalk is the legacy Mac OS protocol for file
and print services. Mac OS X 10.4 uses AppleTalk to discover file
and print services, but no longer supports using AFP over AppleTalk
to send or receive files.
-
Service Location Protocol (SLP) was used for
service discovery in earlier versions of Mac OS X. It has been
superseded by Bonjour but is still supported.
-
SMB, the file sharing protocol for Microsoft
Windows computers, is a service discovery protocol for file and
print services. It can be used as a hybrid system, with dynamic
discovery on the local network and a server-based lookup for
clients on nearby networks.
NOTE
Because of its architecture, SMB clients can
take several minutes to appear on the network.
Configuring Service Discovery
Service discovery in Mac OS X is provided by
Open Directory. Directory Access (/Applications/Utilities)
determines which directory services Open Directory uses and how it
connects to specific directory domains. The Services pane of the
Directory Access application enables you to select and configure
the services that Mac OS X uses to obtain information, including
the service discovery protocols.
To make changes to the service discovery
protocols, you must first click the lock icon in the lower left and
then authenticate by typing the name and password of an
administrator. Then you can select the checkbox next to the
protocol you want to enable or disable. Some services (Active
Directory, BSD Flat File and NIS, LDAPv3, NetInfo, and SMB/CIFS)
are configurable. You can tell a service is configurable if the
Configure button becomes active when you select that service.
You'll learn how to configure these services later in this lesson.
When you have finished selecting and configuring service protocols,
click Apply.
If you know that you don't need a particular
protocol, you can disable it in Directory Access (Bonjour can't be
disabled). If you disable a protocol, Open Directory does not use
it for service discovery on the computer. However, other network
services may still use the protocol. For example, if you disable
the AppleTalk protocol in Directory Access, Printer Setup Utility
can still use AppleTalk to browse for printers whether or not
you've enabled AppleTalk in Network preferences.
Authenticating in Directory
Access
Before you can make any changes in Directory
Access, you must authenticate as an administrator user.
1.
|
Open Directory Access
(/Applications/Utilities).
|
2.
|
Click Services.
If you have not yet authenticated as an
administrator user, the list of services is dimmed.
|
3.
|
Click the lock icon in the lower-left corner.
You will be prompted for a user name and password.
|
4.
|
Use your administrator user name and password
and click OK.
The list entries are no longer dimmed, indicating that you are
authenticated as an administrator capable of configuring the
services.
|
Viewing Configuration Options
You can configure a variety of directory service
options with Directory Access. However, some of these directory
service options are not configurable and can only be enabled or
disabled.
1.
|
In the Services pane of the Directory Access
window, select Bonjour.
Note that the Configure button is dimmed. This is because Bonjour
has no configuration options.
|
2.
|
Select NetInfo.
Note that the Configure button is active for this service because
it has configuration options.
|
3.
|
Click Configure.
A configuration sheet appears.
NOTE
Depending upon your system configuration, your
NetInfo settings may differ from the screen pictured.
|
4.
|
Read the text on the configuration pane, then
click OK.
|
5.
|
Disable the NetInfo service.
|
6.
|
Click SMB/CIFS.
Note that the Configure button is active.
|
7.
|
Click Configure.
A configuration sheet appears. This allows you to enter the
workgroup name and WINS server for SMB discovery.
You can configure your computer to use a specific WINS server for
SMB service discovery. WINS is a Microsoft NetBIOS name server.
WINS servers maintain a name-to-address mapping for networks of
Windows computers, which reduces traffic on the network. If no WINS
server is available to the client, names are looked up on a network
through broadcasts.
|
8.
|
Click Cancel unless you want to configure your
computer to use SMB.
|
|