after you start your ssh session just type screen and start working and if the connection is diconected when you log back in just type screen -ls to list the screen sessions available, output as follows
[rhanna@ramezhanna ~]$ screen -ls
There is a screen on:
10244.pts-0.ramezhanna (Attached)
1 Socket in /var/run/screen/S-rhanna.
cheers . . .