A person asked me this question today, here is my response base on the notes that I had for Solaris system administration certification. Yes. The notes are still handy. ;)
To rlogin/rcp/rsh to a machine without enter a password, you should have
$HOME/.rhosts file defined on the target machine if you are trying to login as root. If you try to login as non-root, make sure the user is in
/etc/passwd and the host you are login from is defined in either
$HOME/.rhosts files. Both
$HOME/.rhosts file should contain the host name that are allowed to connect. Optionally, you can associate a user name with that host name to narrow the permission to just those users. So, the format should look like th following line:
For more information see this pages.