Aaarg! OSX Screen Sharing

[struggle4progress]

Updated OSX on some machines

Macbook with Lion will connect (for screen sharing) to Macmini with Snow Leopard and to a PC running Ubuntu 11.04

Another mac running Snow Leopard used to connect to Macmini running Snow Leopard (but doesn't since I updated Snow Leopard on the mini); it used to connect to the Macbook before I updated Snow Leopard and installed Lion, but doesn't anymore; it still connects to the PC running Ubuntu

The apple forums aren't a great help. It's possible that the final Snow Leopard update is part of the problem, but it's not clear. It can still connect for file sharing

[struggle4progress]

1. Updated the macmini with latest Snow Leopard to Lion. The macbook running Lion

will connect to the macmini running Lion

[struggle4progress]

2. And the macmini running Lion will connect to the macbook running Lion

[struggle4progress]

3. OK. I may have figured out some of this.

I originally setup the macmini to run via screensharing w/o screen keyboard or mouse

This worked fine when I originally did the leopard setup: I could login using any of various accounts to control the default account. Now I've been doing multiple updates: leopard -> final leopard update -> snow leopard upgrade -> final snow leopard update -> lion upgrade. Somewhere along the line, apple may have changed some of the protocols: now, if you try to control default userX's screen by screen-sharing, it's cool if you do it from another machine as userX using userX's password; but if you try to do it from another machine as userY using userY's password (assuming preferences have been set to allow this), then userX gets a popup box asking whether or not to grant permission, and userY gets to wait until userX gives the OK. I don't see that, of course, if I don't have a screen connected to the machine

Similarly, if I decide to log into my lion macbook from a snow leopard machine, by screen-sharing, I succeed if I login as userX when the lion macbook is already controlled by userX. But if I try instead to access the lion macbook screen as userY (even if preferences have been set to allow this), I wander into some wasteland of limbo. An irritating feature of this is that the NetAuthAgent window doesn't have a kill button and it doesn't go away when you you quit screen-sharing or shutdown the machine whose screen you were trying to access: no, you can quit or force-quit it from Activity Monitor (in which case it's likely not to restart again when you need it), or you can reboot

Moreover, for some reason the lion macmini and the lion macbook aren't behaving entirely similarly, although it seems to me the screensharing preferences are the same

:grr:

[struggle4progress]

4. might be one of the snow leopard updates that borks screen-sharing

i updated leopard as far as possible on a macmini, and was able to control the machine by screen sharing

then i started the snow leopard upgrade. when i got through with it, screen sharing still worked. then i started the cycle of repetitive snow leopard updates. screen sharing stopped working. i couldn't get it working no matter what i tried

[struggle4progress]

5. Continued with the lion update on this macmini. Again

the snow leopard machine can share the lion macmini screen -- if I make the screenshare request using the macmini username and password. But using a different (authorized) username and password leads to some unending state of limbo. I can also share the screen if I make the request by asking permission of the current screen, but for me that defeats the purpose of screensharing, since I want to run the macmini without a screen keyboard and mouse

[struggle4progress]

6. This is iffy. One minute I can access the lion macbook from the snow leopard machine.

A few minutes later, I can't

[struggle4progress]

7. Rebooting all machines, I've finally got screensharing working, as far as I can tell

Won't try accessing the snow leopard machine from the lion machines, due to my preset paranoid security precautions. But various other complicated games work