rlogin(1) fails on a machine with the SunOS system installed.
Check the permissions in in.rlogind on the machine you are trying to connect to. The permissions should look like this:
-rwxr-xr-x 1 root staff 16384 Jan 20 1994 /usr/sbin/in.rlogind
Check the login line in the /etc/inetd.conf file. It should look like the following:
login stream tcp nowait root /usr/sbin/in.rlogind in.rlogind
Check /etc/passwd to see if an invalid login shell has been substituted in the entry for the login ID.