You should always consider SSH over TELNET, because of the inherent data encryption features of SSH and the current widespread availability of SSH clients for both Linux and Windows.
By default, the TELNET server isn't installed with Fedora Linux. If you do decide to deactivate an active TELNET server on Fedora, then use the chkconfig command as detailed in Chapter 16, "TELNET, TFTP, and xinetd."
