RSH ou SSH under Tru64

[Consty]

Hi,
I can "rsh" from any unix system to a server under RedHat Linux except Tru64, I get a message like "connexion refused".
In addition I tried "ssh" after generating
a public key, now the problem is that the remote system (linux)asks the password of the the user whereas I have create .rhosts files on both systems.
I would like to use one of these previous commands without password. Thanks for help