Re-blogged from Zahidhaseeb’s Blog:

In my environment I have used Linux Redhat 6.2

• Install three packages telnet-server, telnet and xinetd.
• Make sure that the xinetd service should be running.
• Configure the file name /etc/xinetd/telnet

1.) Install three packages telnet-server, telnet and xinetd.

You need to install three services

for example # yum install telnet-server telnet
the above command will also install the xinetd service. See the following example for reference:

Dependencies Resolved

=====================================================
Package               Arch         Version                  Repository    Size
=====================================================
Installing:
telnet                i686         1:0.17-47.el6            base          56 k
telnet-server         i686         1:0.17-47.el6            base          36 k
Installing for dependencies:
xinetd                i686         2:2.3.14-33.el6          base         121 k

Transaction Summary
=====================================================
Install       3 Package(s)

Total download size: 213 k
Installed size: 409 k

2.) Make sure that the xinetd service should be running.

# service xinetd status
xinetd (pid  13561) is running…

Please also note: Make sure that your firewall also stopped or the telnet traffic is allowed

3.) Configure the file name /etc/xinetd.d/telnet

We need to change the following highlighted line from yes to no

# vi /etc/xinetd.d/telnet
# default: on
# description: The telnet server serves telnet sessions; it uses \
#    unencrypted username/password pairs for authentication.
service telnet
{
flags        = REUSE
socket_type    = stream
wait        = no
user        = root
server        = /usr/sbin/in.telnetd
log_on_failure    += USERID
disable        = yes
}

Note:

In few scenarios, telnet works over the ip, but does not resolve specific ports. In that case xinetd services needs a restart

“service xinetd restart”