I turned on Apple Remote Desktop on my MacBook Pro, but I couldn't VNC into it from my Linux box. However, I could VNC into it from my Solaris 9 box, and from my Mac at home (the one that mattered) with Chicken of the VNC 2.0b2. All Macs running 10.4.10. Linux gave me an unknown message type 242.
Here's what I saw on Linux (184.108.40.206 RHEL4AS):
VNC viewer for X version 4.0 - built Jan 10 2007 07:48:23
Copyright (C) 2002-2004 RealVNC Ltd.
See http://www.realvnc.com for information on VNC.
Fri Jul 6 17:30:58 2007
CConn: connected to host 220.127.116.11 port 5900
CConnection: Server supports RFB protocol version 3.889
CConnection: Using RFB protocol version 3.8
Fri Jul 6 17:31:02 2007
TXImage: Using default colormap and visual, TrueColor, depth 24.
CConn: Using pixel format depth 6 (8bpp) rgb222
CConn: Using ZRLE encoding
CConn: Throughput 20069 kbit/s - changing to hextile encoding
CConn: Throughput 20069 kbit/s - changing to full colour
CConn: Using pixel format depth 24 (32bpp) little-endian rgb888
CConn: Using hextile encoding
unknown message type 242
main: unknown message type
On the other hand, here's what I saw on Solaris 9:
VNC server supports protocol version 3.889 (viewer 3.3)
VNC authentication succeeded
Desktop name "a.b.c.d"
Connected to VNC server, using protocol version 3.3
VNC server default format:
32 bits per pixel.
Least significant byte first in each pixel.
True colour: max red 255 green 255 blue 255, shift red 16 green 8 blue 0
Using default colormap which is TrueColor. Pixel format:
32 bits per pixel.
Most significant byte first in each pixel.
True colour: max red 255 green 255 blue 255, shift red 0 green 8 blue 16
So if I can use something other than Linux, my VNC viewer to Apple Remote Desktop works. I wonder if Linux is just using a newer version (RFB remote frame buffer protocol version 3.8 instead of 3.3) ... but (intelligent!) backwards compatibility would be nice! I really didn't troubleshoot any further than this because it was Friday evening, and I could go home if I had reasonable confidence that I could VNC in to my MacBook Pro. Since Solaris worked, I didn't much care why Linux failed. Sure enough, my Mac at home also worked, so I went about finishing that long task, and enjoying my precious weekend.
Update: solved 10/02/2007!