Virtual Network Computing (VNC)

Probably the most useful Open Source tool of all (ok, maybe SSH is more useful), VNC was originally created by the AT&T Research facility in Cambridge and is a remote display protocol that, despite being rather inefficient (something modern forks try to improve upon, but certainly still less than RDP), has the advantage of being very simple and require only very light clients (the Windows binary is contained within just 230KB, and Java implementations can be downloaded on-the-fly from any browser).

Mac OS X includes a VNC server (check the Sharing preference pane, it’s part of Apple Remote Desktop).

Mac Screen Sharing

Apple uses a variant of the VNC protocol for its own screen sharing solution, and this article has some useful tweaks to the Leopard built-in client that I’m reproducing here for safekeeping:

Displaying a Bonjour browser:

defaults write ShowBonjourBrowser_Debug 1

Displaying additional controls: (pre-10.5.5)

defaults write \
'NSToolbar Configuration ControlToolbar' -dict-add 'TB Item Identifiers' \

In 10.5.5, Apple decided to get stingy again, so this workaround became necessary. Which is kind of ridiculous.

When Snow Leopard rolled around, they broke even more of the UI, but it’s still possible to set display quality via a preference (via):

defaults write controlObserveQuality n

…gives you:

  1. black and white
  2. grayscale
  3. 8-bit color
  4. 16-bit color
  5. full color


Not all of these are related to VNC, but VNC has been used for things like multi-machine (i.e., having two different machines side by side and move the mouse/keyboard across machines) for a long time now and is better understood by most people, so I’ve lumped everything here:

Category Date Link Notes
Servers May’12 VirtualGL Finely tuned OpenGL encapsulation (with server-side hardware acceleration).
Older Schnitz Remote Remote for reverse connections.
Alkit VNC allows single-window sharing.
RealVNC the original (and still the reference) implementation. Also has the most efficient client (old homepage)
Vine Server native Mac OS X server, supporting multiple simultaneous remote sessions
Ultra VNC Single-Click Server a nice, customizable Windows server that helpdesk staff can e-mail to someone in need of help.
MetaVNC an intriguing way to share single windows
Reinventing the wheel Apr’11 noVNC A decent, secure websockets/canvas client.
Apr’10 Ajax VNC A “Clientless” VNC solution implemented with canvas and, regrettably, a Java server.
Clients (Mac) Dec’08 JollysFastVNC The best client out there in terms of speed and international keyboard support.
VNCDimension partial support for non-US keyboards (but no dead keys) and very fast graphical updates.
Chicken of the VNC No international key support, works OK with the built-in Mac OS X server.
VNCThing read my blog entry for more (and a link to the source code).
Workspot modified VNC Tried it once.
Clients (Other) Jun’12 pyvnc A ctypes client that uses libvnc directly.
May’09 vnc2dl a client that renders on a DisplayLink device.
Older FlashVNC a Flash viewer
MochaVNC for Palm and Pocket PC, supports post-3.3 procotol versions and has a built-in SSH tunneler.
PVNC for the PlayStation Portable (has some ARM code, if I remember correctly)
DirectVNC framebuffer-based clients.
Palm VNC with server-side scaling extensions
Enhanced Full-Screen Clients
SSHVNC a combined client
Tools Aug’11 Gitso A reverse VNC connection tool for support purposes.
Older VNC Snapshot can take screenshots of a section of the display and save them in JPEG format
VNCj a nice way to serve Java AWT applications
Vnc2swf a Flash recording tool, which now has an editing tool available.
LibVNCServer also has a client library
perlVNC fear.
PyVNC – a Python VNC client
VNC Reflector
Multi-Machine (a2b) Older SynergyKM Synergy packaged as a preference pane, as it should. Verified working in 2008 under Leopard.
Synergy a platform-agnostic package focused on precisely this application – QuickSynergy is a very nice repackaging.
osx2x does it all, Mac to X or VNC
x2vnc X to VNC
win2vnc Windows to VNC, not multi-monitor friendly, (another version which is multi-monitor friendly)
x2x the original concept, for completeness


My current (minimalist) Xvnc startup file for Linux, so that I remember that unsetting SESSION_MANAGER is the right way to avoid complaints from gnome-session:

$ cat .vnc/xstartup
[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
gnome-session &

See Also

Go (lang)JavaPythonWindows
RDPMore Raspberry Pi 2 BenchmarkingRaspberry PiMy Deep, Dark Secret
How to install Ubuntu on your Android phoneDesktop Streaming to the Raspberry Pi using VLC and H.264ElementaryExpanDrive 3
An ARM On Four CylindersThe X Window SystemThe Switcher's Application GuideHow to Switch to the Mac
A Big Slice of Raspberry PiVirtual Network Computing (VNC)The Week That Wasn'tThree
Scoring 2011's predictionsI swapped my MacBook for an iPad+LinodeMyriad's Alien Dalvik streamed to an iPadSnow Leopard
Jedi Mind Tricks2011 is upon usSo, what of the netbooks?Today In The Geek Plane
Thin ThoughtsBonjourJPEGLeopard
On The CuspCitrix To Bring Millions of Windows Apps To iPhoneOn Apple, Netbooks, and My Line of WorkVMware/Fusion
Tale of a NetbookSSH tunneling setup scriptsFoxes on fire, and other entertainmentDisplayLink
SSHDisplayLink's new VGC 4.3 supports Vista Aero 3DHear The Leopard Spots RoarRadar Bugs I'd Like To See
Random Desktop ShotVNC and Monitor AnticsJollysFastVNCMy Five Wishes for Leopard
xrdp is now in DebianWebVNC - VNC on your iPhonePalmFlash
The Minimalist Remote Access KitSchnitz RemoteThings I Can't Get Around To Do, Part OneMore Heads Than One
ScreenRecyclerTrips Down Memory LaneNXBacklog
Mac OS XXubuntu - The Mouse With GlitzMacOn Mark's un-Switching, and Lemmings
You Know You're Becoming a Luddite When...Thin PushbackNetwork ComputingQuentin Stafford-Fraser
The Razor-Thin Mobile ComputerAppleThe Tele Teaching ToolVMware Server
Poor Man's Screen SharingPlaceless GTDIdle ModeFinally, a Reason to Look at Vista
The Hours of Service Pack 2A Few Notes on the PlayStation PortableRacing Towards The New YearPlayStation Portable
Miscellaneous OdditiesQuickSynergyNokia 770 WishesMinor Updates
Plug Me InDances With VMwareChilling OutNetMeeting
Could We Have Real Collaboration, Please?Take TwoRandom Thoughts On Nomadic LifeRandom Thresholds Of Feasibility
Miscellaneous Remote GeekeryFive Random Annoying Things That I've Had To Put Up With This WeekRemotely PossibleHeat, TV and Data Retention
Somewhat HazyCooling OffMice and CakeStrange Day
By Special RequestLast Round Of Relaxation3G On Your MacCoding Challenge: Build the best VNC client for the Mac
Ten Open Source Projects Worth Keeping Track OfMini MadnessWorkshop DayInterstitial Progress
Five Bits Of NewsLittle GripesToday Has Got To Be A Wierd DayThe Top Five Mac OS X Applications I Can't Live Without
Things You Should Try14The Usability WarsLink Mode (Again):
MIDPToo Many Machines?Dual Burn-InContext Switching
Pocket PC/VNCViewerDon't Try This At HomePraise the MacJ2ME
Work In Progress