Notes on using screen to collaborate

Scenario:

Alice wants to collaborate with Bob.
Her home network is called alice.net and she has two machines, edge and dev.
Port 22 on alice.net is open and forwards to edge.
Dev is not exposed through her router. It is the machine where she does her work and wants to allow collaboration.
Alice wants to use screen to share a terminal session with Bob.

Setup:

On edge Alice creates a user account guest that will be used by Bob.
Alice does the following to create a reverse tunnel from dev to edge:
- ssh -N -R '*:2200:localhost:22' edge
Bob will be connecting to port 2200 so Alice must open that port on her router and forward it to edge.
To use screen in multiuser mode, it must run as root with setuid. Alice must do the following on dev:
- sudo chmod +s /usr/bin/screen
- sudo chmod 755 /var/run/screen

Sharing a screen:

Alice starts screen screen -S shared. She then does the required configuration:
- ctl-a :multiuser on
- ctl-a :acladd guest
Bob connects by using ssh -p 2200 guest@alice.net
He'll be prompted for the guest user UNIX password.
Once logged in he connects to the screen using screen -x alice/shared

Next steps:

Get per user credentials to work as shown in the LOSA guide
- Our scenario is more complicated in that Alice doesn't want to allow Bob to connect using her account. She also doesn't want to work in a dumbed-down guest account. What to do?
- The user files in a normal SSH set up are in /home/$user/.ssh/authorized_keys, not in /etc/ssh/user-authorized-keys as shown in the LOSA write up.

Tips:

References:

launchpad development