AHPCC has three login nodes. I used screen all the time. But the login nodes were randomly assigned. Sometimes, I need to check all the screen sessions at each login node.
To avoid input annoying password every time switch to other login nodes, I used the following way. (Got help from Pawel)
In the ~/.ssh folder, generate your own ssh-key (check my previous post please). Then
cat id_rsa.pub >> authorized_keys