Telnet server

Telnet offers users the capability of running programs remotely and facilitates remote administration. Telnet is available for practically all operating systems and eases integration in heterogeneous networking environments.

 so to start it you must have telnetd  deamon (ubuntu user)
#apt-egt install telnetd

 (fedora user)
# yum install telnet-server telnet

we can find its configuration file at
    /etc/inetd.conf

remove comment from this file and make following line look like this:
 /usr/libexec/telnetd telnetd

enable inetd service so that telnet get loaded
#vi /etc/rc.conf

add
inetd_enable="YES"

Restart telnet
#/etc/init.d/xinetd restart

to check configuration of telnet
# chkconfig telnet on

for more help