General
Considerations
Apple Remote Desktop (ARD)
Virtual Network Computing (VNC)
Written
By: Adam Rosen
This article was published in the Adam's
Apple column on Low End
Mac
Remote control of your Macintosh allows you to access a remote (host)
computer across a network or the Internet from another local (client)
system. The screen of the shared host computer appears locally, and
you use your local mouse and keyboard to control the other system from
afar. Historically there have been fewer options to accomplish this
for Macs than PCs, but the situation has been improving steadily.
Part
1 of this article covers 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 will address some commercial solutions that also support
multiple OS versions, along with how to force-reboot a remote Mac. Part
3 will focus on new options provided by Mac OS X 10.5 Leopard.
General Considerations
Remote
control capabilities vary by method used, and include remote desktop
control (screen sharing), file transfers, and system management (patches
and updates). With any remote desktop method, access to the remote system
is slower than when you are sitting in front of the computer. The method
used, network bandwidth available and types of traffic will vary the
"sluggishness" factor.
Minimizing
the amount of data you need to transmit for screen sharing will make
the process run more quickly. Closing unnecessary windows on the remote
system and using a flat single color desktop (instead of a complicated
picture or pattern) will speed up response. Patience is a must, but
remember it's usually faster than traveling there!
Needs
and realities often dictate your options. Some remote control methods
work across different versions of Mac OS X (or cross-platform), while
others require the same OS version on local and remote ends. Some methods
require you to know the IP address of your remote system to connect
and may require special firewall configurations, while others will work
without any special settings or knowledge... usually!
It's often
helpful to use 2 remote control methods simultaneously if possible,
especially if you're running a server or access is otherwise critical.
Programs crash, network and Internet conditions vary, and you may find
yourself locked out at a critical time. Sometimes method B works when
method A doesn't, then you can fix method A or reboot the machine from
afar.
Apple Remote Desktop (ARD)
Apple's native remote control solution is Apple Remote
Desktop (ARD). ARD server software has been built-in to Mac OS X since
10.3 Panther, and was available as an optional install for older OS
X versions. ARD provides the full gamut of remote system control - scalable
screen sharing, file transfers to and from the remote systems, and remote
software updating of individual machines and whole networks at a time.
On a LAN, network admins with multiple Macs to manage will find this
tool indispensable.
To enable an ARD host (server) in Panther and Tiger,
go to System Preferences --> Sharing and turn on Apple Remote Desktop,
then click Access Privileges and enable all desired services
for one or more users. In Leopard you also enable ARD via System Preferences
--> Sharing, but control capabilities have been split into separate
Screen Sharing and Remote Management sections; click Options
for choosing Remote Management services. ARD access from afar is via
your host Mac's account password.
To control an ARD-shared host computer, you need to
use the Apple
Remote Desktop administrator software. Apple sells two
versions, a 10-client version for $299 or an unlimited client version
for $499. The client limit dictates how many remote systems you can
manage simultaneously; most home users and small business will be fine
with the 10-client version. Bonjour support is available to find systems
on your local network, or you can add by IP address.
Across the internet you must know the IP address of
the remote computer or network gateway to establish a connection; this
requires either a static IP address on the remote end or the use of
a dynamic DNS locator service (like DynDNS)
to find your remote system in times of need. ARD requires forwarding
TCP and UDP ports 3283 through firewalls. Traffic can be routed across
VPNs if one is available.
ARD is a powerful tool, but power comes at a price.
Fortunately for home and small business users there are other options.
Virtual Network Computing (VNC)
VNC
is an open source software effort to provide cross-platform remote screen
sharing capabilities. Long an option for Windows, VNC support was spotty
on Mac OS 9 but solid on Mac OS X and has become my primary method of
controlling remote Macs and PCs from other Macs (and PCs) when static
IP addresses are available.
The remote
Mac needs to run a VNC server; starting with Mac OS X 10.4 Tiger the built-in ARD
software has included the option to use VNC for screen sharing.
Go back to System Preferences --> Sharing --> Apple Remote Desktop
(Tiger) or Screen Sharing (Leopard) and click the Access Privileges
or Options button (as applicable). Enable "Share Screen
with VNC clients" and use a strong password.
On pre-Tiger
Macs or as an alternate option for all Macs, the free Vine
VNC Server (for OS X and OS 9) and it's older
precursor, OSXvnc,
offer excellent VNC server packages with more options than Apple's built-in
server. In my experience the Vine and OSXvnc packages are more stable
and resilient than Apple's built-in server - I've had onboard VNC stop
working and require a reboot to fix many times, while the standalone
server rarely fails. I use Vine VNC Server on many of the business systems
I support.
A VNC
client viewer application is required to view your remote Mac on your
local system. Apple did not provide a VNC viewer in Mac OS X until Leopard
(see Part 3
of this article), but the open source market came earlier to the rescue.
Chicken
of the VNC is a good free VNC viewer with a silly name,
and runs on Mac OS X 10.3 Panther through 10.5 Leopard.
For a
step up, $35 will get you the Vine
VNC Viewer; this software is faster and stabler than Chicken
of the VNC and offers screen size scaling (invaluable when controlling
a big screen from a small laptop) and clipboard sharing. Mac OS X Tiger
or Leopard is required.
Both
Vine and Chicken of the VNC will find local network systems using Bonjour.
Across the Internet you will need to know the IP address of the remote
computer or use a dynamic DNS locator service. VNC uses TCP port 5900
for control and as with ARD requires port forwarding through firewalls
and routers. VNC works fine across VPNs.
VNC provides
screen sharing capabilities without file transfers. To work around this
limitation you can use a network and/or internet-accessible resource
that both systems can reach: an FTP server, a shared Mac disk using
AFP (AppleShare), a shared Windows volume using SMB, or a webserver
with upload/download capability. Post the software or document from
one system and grab it from the other via your shared disk or server.
Adam Rosen
