Mac OS X: Screen Sharing

How to enable a screen sharing of a remote Mac (10.6) if you forgot to enable it and your Mac is behind a firewall?

This is the question I asked myself today when I desperately was in need to use some GUI on my Mac Pro at work place, while I am on a business trip right now and have my laptop with me :(

Same as always with the Mac OS X - it appeared to be very easy to implement.

So, you have a remote Mac "A", which is behind a firewall and you want to connect to it via an open domain "B" (to where ssh is possible) from your local Mac (a laptop, for example).

STEP #1

Enable an SSH tunnel via an open domain to you remote Mac. On your local Mac just open a terminal and enter the following:

ssh -N -L 3000:loginnameA@hostnameA:5900 loginnameB@hostnameB

The command will create a tunnel and hang. When you are done terminate the command and the tunnel will be disabled.

STEP #2

Open another terminal on your local Mac and ssh to your remote Mac to enable a screen sharing:

sudo /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/kickstart -activate -configure -access -on -clientopts -setvnclegacy -vnclegacy yes -clientopts -setvncpw -vncpw mypasswd -restart -agent -privs -all

STEP #3

Start sharing the screen :)

In Safari enter the following URL: vnc://localhost:3000

Should work now :)

Disable screen sharing

SSH to your remote Mac and execute the command:

sudo /System/Library/CoreServices/RemoteManagement/ARDAgent.app/Contents/Resources/kickstart -deactivate -configure -access -off

Don't forget to terminate the SSH tunnel (Step #1).

Hope it helps some one to save time.