SSH Public Key Authentication

# generate a public/private keypair on host you want to connect from
ssh-keygen -t rsa
(enter passphrase if you like)
# copy public key to host you want to connect to
# make sure we do not overwrite an authorized_keys2 file 
# on the server side by checking there first!
scp ~/.ssh/id_rsa.pub someuser@someserverhost:/home/someuser/.ssh/authorized_keys2
# This should work without asking for a password now on the host you want to connect from:
ssh -l someuser someserverhost