Screen
Sharing.app
Back to My Mac
iChatAV
Mac
OS X Server Admin
Written
By: Adam Rosen
This article was published in the Adam's
Apple column on Low End
Mac
Part
1 of this article covered general considerations and Apple-supported
methods available for remote system control that will generally work
on any version of Mac OS X (Jaguar, Panther, Tiger and Leopard). Part
2 addressed some commercial solutions that also support
multiple OS versions, along with how to force-reboot a remote Mac.
With
the introduction of Mac OS X 10.5 Leopard, Apple upped the ante on Mac
remote control. All of the previously covered methods still work, but
new options now exist in the operating system or via associated services.
Screen Sharing.app
Apple
now offers a Remote Desktop (ARD) and VNC viewer application for screen
sharing called "Screen Sharing" (how original). On a local
network shared systems will appear via Bonjour in the Finder's sidebar.
Click on them and you'll see a Share Screen... button. Access is usually
fast and elegant on a local network, although shared
systems sometimes come and go in the sidebar. Restarting the local and/or
remote Mac usually fixes the problem. I attribute this behavior to bugs
in early Leopard releases, and suspect this will become more stable
with subsequent updates.
You can
use Screen Sharing to access remote systems not on your local network,
but you need to manually launch the program and know the IP address
of the remote computer. Screen Sharing.app is located in System/Library/CoreServices
(along with lots of other useful things). Don't move the program
from this location, instead put an alias in the dock or on the
desktop for easy access. When launched this way you will be asked for
the IP address of a server to connect to.
Power
users may want to turn on a hidden window of the Screen Sharing app
by entering these lines at a Terminal prompt:
LocalMac:~
localuser$ defaults write com.apple.ScreenSharing ShowBonjourBrowser_Debug
1
This adds a menu of VNC enabled systems accessible via Bonjour. Screen
Sharing.app is a basic VNC viewer, but will satisfy many users and the
price is right.
Back to My Mac
A companion
service for remote system control across the internet is Apple's Back
to My Mac capability. You must have a current .mac account to use this
service ($99/year) and all systems must be running Leopard. Use the
.Mac System Preference Pane to login to the same .mac account on both
systems and enable Back to My Mac on each machine. On the Mac to be
controlled, you must also enable Screen Sharing and (if desired) File
Sharing from the Sharing Preference Pane.
On the
control (local) Mac, when you're away from your home or office the remote
Mac should show up in the Finder's sidebar. You can choose to share
the remote screen using Screen Sharing or mount one or more drives if
File Sharing is enabled. The combination provides the one-two punch
of (scalable) screen sharing and file transfers, and when it was available
worked very efficiently in my tests.
There's
one big potential impediment to Back to My Mac working correctly, however:
both the local and remote network routers must support pass through
of Universal Plug'n'Play (UPnP) services. Some routers do this by default,
some can be configured appropriately, and others are incompatible. At
my home office I could not get a Sonicwall TZ170 small business router
configured to pass Back to My Mac traffic, but an inexpensive Linksys
WRT54G worked fine. Apple says their Airport Extreme routers support
Back to My Mac, and makes this
list available regarding third party hardware.
One security
consideration: once enabled this service is available for anybody who
has access to your .mac account. Apple recommends using a strong password
for .mac, which is always a good idea, but for additional security turn
on Fast User Switching on the remote system in System Preferences -->
Accounts --> Login Options. This creates a menu with your account
name in the right side of the menu bar. Choose "Login Window"
from this menu when you're done using your shared machine or otherwise
away from home to hide the screen and require a password for subsequent
access.
iChatAV
iChat continues to mature and expand in capability,
and with Leopard has expanded to include screen sharing and file transfer
capabilities. Implementation is excellent, and for the computer guy
or gal in the family who always has to support their parent's and grandparent's
computers Apple has delivered a nice - and free - solution with this
package. For this option somebody needs to be present at the remote
computer during the session.
You will need a different iChat account setup on both
systems to establish communication; you can use an existing .mac or
AIM account if one is available, otherwise you can signup for an iChat
account upon first launch. On a local network iChat can also use Bonjour
to find remote systems, but this option in initially disabled in iChat
preferences. You must have Leopard on both systems, and iChat must be
launched on both Macs before attempting a connection.
The remote system will show up in either the AIM Buddy
List or the Bonjour List, depending on protocol used. Double click a
name to connect a chat session. The remote system will be prompted to
accept the incoming connection (here's where the remote user assistance
is needed), then off you go.
Once connected use the Buddies menu and "Ask
to Share" the remote screen. Another dialog box at the far end
requires acceptance of the sharing request. Apple uses it's graphics
wizardry to show both the local and remote screens, properly scaled,
simultaneously on your screen. Very slick. Click on the smaller window
in the bottom right corner to switch between local and remote screens.
To transfer files, go to the Buddies menu and choose
"Send File..." The remote user must again accept the request.
Once transferred the sent file shows up in the Downloads folder in the
remote user's home directory.
By itself iChat doesn't make a good option for unattended
systems due to the acceptance prompts which must be answered on the
remote end before an action takes place. For attended remote desktop
systems, or as a second option where you have another screen sharing
solution in place like VNC, iChat is a viable solution. You don't need
to know any IP addresses or perform firewall configurations, and can
perform file transfers between computers. You also have good security
since you don't have to leave the remote control on at all times - when
you quit iChat the session is done.
Mac OS X Server Admin
As
a final option, system administrators running the Leopard version of
Apple's Server Admin application can take advantage of Apple's built
in screen sharing (ARD/VNC) direct from Server Admin.app - just choose
Share Screen from the File menu when connected to a remote server. I
typically use VNC alongside the Server Admin app for this purpose, but
it's always nice to have multiple options.
Leopard
and Leopard Server both show a maturation of remote access and sharing
capabilities, which is welcomed on the Macintosh. Options should only
improve with time.
Adam Rosen
