rsh

It looks like RH uses xinetd, so parts of this page may be useful:

http://www.redhat.com/docs/manuals/linux/RHL-7.2-Manual/ref-guide/s1-pam-rexec.html

(1) install rsh-server rpm.

(2) run serviceconf and enable rexec, rsh and rlogin

(3) /sbin/service xinetd restart